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142-725: The aquarium opened on June 14, 1986, as the Virginia Marine Science Museum. The focus of exhibits was on life in the rivers of Virginia, Chesapeake Bay , and the marine waters just off of Virginia. In 1995, the aquarium expanded, tripling its size. On November 21, 2009, the Virginia Aquarium opened a 12,000 square feet (1,100 m) series of exhibits called Restless Planet. The $ 25 million renovation designed by Chermayeff & Poole of Boston includes for habitats: Malaysian Peat Swamp, Coastal Sahara Desert, Red Sea, and Indonesia's Flores Island and doubled

284-517: A diurnal ecological equivalent. The great horned owl is one of the earliest nesting birds in North America , often laying eggs weeks or even months before other raptorial birds. The great horned owl was formally described in 1788 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus 's Systema Naturae . He placed it with the other owls in

426-469: A female. Despite its camouflage and cryptic locations, this species can still sometimes be spotted on its daytime roosts, especially by American crows ( Corvus brachyrhynchos ). Since owls are, next to red-tailed hawks , perhaps the main predator of crows and their young, crows sometimes congregate from considerable distances to mob owls and caw angrily at them for hours on end. When the owls try to fly off to avoid this harassment, they are often followed by

568-443: A glide as well. The stiff feathering of their wings allows owls to produce minimal sound in flight while hunting. Almost all prey are killed by crushing with the owl's feet or by incidentally stabbing of the talons, though some may be bitten about the face as well. Prey is swallowed whole when possible. When prey is swallowed whole, owls regurgitate pellets of bone and other non-digestible bits about 6 to 10 hours later, usually in

710-573: A handful of prey species: three species of lagomorph : the eastern cottontail ( Sylvilagus floridanus ), the snowshoe hare ( Lepus americanus ) and the black-tailed jackrabbit ( Lepus californicus ); two species of New World mice : the white-footed mouse and the North American deermouse ( Peromyscus leucopus & maniculatus ); approximately three species of vole : the meadow , prairie and woodland voles ( Microtus pennsylvanicus, ochrogaster & pinetorum ); and one introduced pest,

852-485: A large Atlantic goliath grouper , Atlantic tripletail , cobia , lookdown , and permits . The new Restless Planet expansion includes five immersive displays (a Malaysian peat swamp, the coastal desert, a replica of the Mediterranean Sea, the 100,000-US-gallon (379,000 L) Red Sea exhibit and a recreation of an Indonesian volcanic island), and new hands-on exhibits intended to show the forces that shaped

994-562: A large head, and broad wings. Its size can vary considerably across its range, with populations in interior Alaska and Ontario being largest and populations in California and Texas being smallest, though those from the Yucatán Peninsula and Baja California appear to be even smaller. Adult great horned owls range in length from 43 to 64 cm (17 to 25 in), with an average of 55 cm (22 in), and possess

1136-483: A large outdoor play area for kids, with water tables, climbing nets, bubbles, and more. The Research and Conservation branch of the aquarium is responsible for the Stranding Response Program, which responds to sick or injured seals , dolphins , whales , and sea turtles from local shores. The Marsh Pavilion closed to the public for renovations on January 2, 2019. The Virginia Aquarium Aviary

1278-423: A more complete picture of the diversity of prey consumed, but prey remains outside of pellets may provide clues to prey excluded from the pellets and a combination of both is recommended. Many large prey items are dismembered. Great horned owls may behead large prey before taking it to its nest or eating perch. The legs may also be removed, as may (in some bird prey) the wings. The great horned owl will also crush

1420-505: A neighboring female had died or emigrated, suggesting that territorial defense may be sex-specific. At least four dead great horned owls in Kluane were apparently killed by others of their own species in territorial conflicts. Owls killed by other horned owls are sometimes cannibalized, although the origin of the killing may have been territorial aggression. Northern populations occasionally irrupt south during times of food shortage, but there

1562-644: A number of species, adding oxygen to the water and improving water clarity." Other vegetation that makes its home in other parts of the bay are wild rice , various trees like the red maple , loblolly pine and bald cypress , and spartina grass and phragmites . Invasive plants have taken a significant foothold in the bay. Plants such as Phragmites, Purple loosestrife and Japanese stiltgrass have established high levels of permanency in Chesapeake wetlands. Additionally, plants such as Brazilian waterweed , native to South America, have spread to most continents with

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1704-438: A predominantly rod retina . The great horned owl's eye contains both rods and cones like most species that see in color, but the vision of a great horned owl closely resembles that of many other nocturnal species. The peak wavelengths that are observed by the cones is 555 nm and the research suggests that the great horned owl has relatively weak color vision, especially compared to other bird species. Despite (or perhaps as

1846-566: A preserved specimen, and another specimen formed part of the Leverian collection . The great horned owl is now placed in the genus Bubo that was introduced in 1805 by André Duméril . The great horned owl represents one of the one or two radiations of the genus across the Bering land bridge to the Americas . Whereas the lesser horned owl clearly divided once the owl had spread through

1988-543: A result of) the poorer sense of color vision, the owl manages to have excellent night vision. Instead of turning its eyes, an owl must turn its whole head, and the great horned owl can rotate its neck 270°. The iris is yellow, except in the amber-eyed South American great horned owl ( B. v. nacurutu ). The great horned owl's song is normally a low-pitched but loud ho-ho-hoo hoo hoo (or also transcribed as bu-bubu booh , who-hoo-ho-oo or who-ho-o-o , whoo-hoo-o-o , whoo ) and can last for four or five syllables. The call

2130-531: A rope climbing course. Together the two buildings are home to more than 12,000 animals representing over 700 species. The Main Building houses displays intended to show the journey of water from the rivers of Virginia, through the Chesapeake Bay , and out into the ocean. The Restless Planet part of the displays are intended to show the forces that shaped Virginia. The Chesapeake Bay Aquarium starts with

2272-562: A snag, pole or other high perch. During hunting forays, they often fly about 50 to 100 m (160 to 330 ft) from perch to perch, stopping to survey for food at each, until they sense a prey item below. From such vantage points, owls dive down to the ground, often with wings folded, to ambush their prey. Effective maximum hunting distance of an owl from an elevated perch is 90 m (300 ft). Due to their short but broad wings, great horned owls are ideally suited for low speed and maneuverability. Despite reports that they do not hunt on

2414-688: A territory, and leave regions with little food in winter. In most aspects of their behavior, great horned owls are typical of owls and most birds of prey. Like most owls, the great horned owl makes great use of secrecy and stealth. Due to its natural-colored plumage, it is well camouflaged both while active at night and while roosting during the day. During the daytime it roosts usually in large trees (including snags & large hollows but usually thick branches) but may occasionally be in crevices or small caves in rocks or in dense shrubbery. Pine and other coniferous trees may be preferred where available since they are particularly dense and provide cover throughout

2556-580: A touch pool where visitors can touch horseshoe crabs , Forbes' sea stars , and whelk . The rest of the exhibit showcases species that live in the shallow waters around the Chesapeake Bay Bridge-Tunnel including hermit crabs , spider crabs , and Hypsoblennius hentz . The Norfolk Canyon aquarium replicates the underwater environment of the Norfolk Canyon, a canyon roughly 70 miles off the coast of Virginia. This exhibit

2698-776: A village location at the bay's mouth." The Chesapeake Bay is an estuary to the North Atlantic, lying between the Delmarva Peninsula to the east and the North American mainland to the west. It is the ria , or drowned valley, of the Susquehanna River , meaning that it was the alluvial plain where the river flowed when the sea level was lower. It is not a fjord , because the Laurentide Ice Sheet never reached as far south as

2840-439: A wingspan of 91 to 153 cm (3 ft 0 in to 5 ft 0 in), with an average of 122 cm (48 in). Females are somewhat larger than males. Mean body weight is 1,608 g (3.545 lb) for females and 1,224 g (2.698 lb) for males. Depending on subspecies, maximum weight can reach 2,503 g (5.518 lb). The wing chord length is 297–400 mm (11.7–15.7 in). The wing loading ,

2982-709: Is 11,684 miles (18,804 km), circumnavigating a surface area of 4,479 square miles (11,601 km ). Average depth is 21 feet (6.4 m), reaching a maximum of 174 feet (53 m). The bay is spanned twice, in Maryland by the Chesapeake Bay Bridge from Sandy Point (near Annapolis ) to Kent Island and in Virginia by the Chesapeake Bay Bridge–Tunnel connecting Virginia Beach to Cape Charles . Known for both its beauty and bounty,

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3124-605: Is a near threatened species that inhabits the wetlands. Larger fish such as Atlantic sturgeon , varieties of sharks, and stingrays visit the Chesapeake Bay. The waters of the Chesapeake Bay have been regarded as one of the most important nursery areas for sharks along the east coast. Megafaunas such as bull sharks , tiger sharks , scalloped hammerhead sharks , and basking sharks and manta rays are also known to visit. Smaller species of sharks and stingrays that are known to be regular to occasional residents in

3266-479: Is a growing industry in the bay. Oyster aquaculture is passive in that the bay provides all the natural oyster food needed, making it an environmentally friendly practice in contrast to other kinds of fish farming. Oyster farms provide jobs as well as a natural effort for filtering excess nutrients from the water in an effort to reduce the effects of eutrophication pollution (too much algae). The Chesapeake Bay Program promotes oyster restoration projects to reduce

3408-414: Is a main feature for tourists who visit Maryland and Virginia each year. Fishing, crabbing, swimming, boating, kayaking, and sailing are extremely popular activities enjoyed on the waters of the Chesapeake Bay. As a result, tourism has a notable impact on Maryland's economy. One report suggested that Annapolis was an appealing spot for families, water sports and boating. Commentator Terry Smith spoke about

3550-415: Is approximately 20 miles (32 km) long; it has trestle bridges as well as two stretches of two-mile-long (3.2 km) tunnels that allow unimpeded shipping; the bridge is supported by four 5.25-acre (21,200 m ) man-made islands. The Chesapeake Bay Bridge – Tunnel was opened for two lanes in 1964 and four lanes in 1999. Tides in the Chesapeake Bay exhibit an interesting and unique behavior due to

3692-663: Is approximately 200 miles (320 km) long from its northern headwaters in the Susquehanna River to its outlet in the Atlantic Ocean. It is 2.8 miles (4.5 km) wide at its narrowest (between Kent County's Plum Point near Newtown in the east and the Harford County western shore near Romney Creek) and 30 miles (48 km) at its widest (just south of the mouth of the Potomac River which divides Maryland from Virginia). Total shoreline including tributaries

3834-456: Is home to sandbar shark , nurse shark and sand tiger shark as well as fish such as crevalle jack , grey triggerfish and southern stingray . The 70,000-US-gallon (265,000 L) Chesapeake Light Tower Aquarium replicates the underwater environment of up to about 15 miles (24 km) off the coast of Virginia, and is home to loggerhead , green sea turtle , and Kemp's ridley sea turtle along with many fish including Atlantic spadefish ,

3976-548: Is in the range of 4 g (0.14 oz) ( shrews ) to 2,300 g (5.1 lb) ( jackrabbits ). A single owl requires about 50 to 100 g (1.8 to 3.5 oz) of food per day and can subsist on a large kill over several days. Despite the great diversity of prey taken by these predators, in most of the continental United States from the East to the Midwest as well as Canada and Alaska , great horned owls largely live off just

4118-432: Is indisputable. By winter in areas that hold heavy snow, Peromyscus mice often come to outnumber the voles in the diet since the mice tend to travel over the surface of the snow while the voles make tunnels underneath the snow. In fact, a healthy family of great horned owls can decimate a colony of field rats, thus potentially performing a key role in controlling a highly destructive pest. Great horned owls living in

4260-638: Is less common in the more extreme areas of the Americas. In the Mojave and Sonora Deserts , they are absent from the heart of the deserts and are only found on the vegetated or rocky fringes. Even in North America, they are rare in landscapes including more than 70% old-growth forest, such as the aspen forest of the Rockies. They have only been recorded a handful of times in true rainforests such as

4402-594: Is no annual migration even at the northern limits of the great horned owl's range. Hunting tends to peak between 8:30 pm and midnight and then can resume from 4:30 am to sunrise. Hunting tends to be most prolonged during winter by virtue of prey being more scarce. However, great horned owls can learn to target certain prey during daylight in the afternoon when it is more vulnerable, such as eastern fox squirrels ( Sciurus niger ) while they are building their leaf nests and chuckawallas ( Sauromalus ater ) sunning themselves on desert rocks. Owls hunt mainly by watching from

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4544-457: Is not fully understood, but the hypothesis that they serve as a visual cue in territorial and sociosexual interactions with other owls is generally accepted. The great horned owl is the heaviest extant owl in Central and South America and is the second-heaviest owl in North America, after the closely related but very different-looking snowy owl. It is heavily built, with a barrel-shaped body,

4686-486: Is not supported by genetic evidence, which places them in separate clades of their genus. Genetic testing indicates that the lesser horned owl, and then the snowy owl, not the Eurasian eagle-owl, are the most closely related living species. Pleistocene era fossils have been found of Bubo owls in North America, which may either be distinct species or paleosubspecies , from as far east as Georgia , but predominantly in

4828-550: Is performed by males, but females frequently assist their partners in hooting contests with neighbors or intruders, even during incubation. On occasion, although territory borders may be successfully maintained via vocalizations alone without even seeing the competing owl, such confrontations may turn physical, with various levels of threats distinguished. The highest threat level involves the spreading of wings, bill-clapping, hissing, higher-pitched screams of longer duration, with general body poised to strike with its feet at intruder. If

4970-602: Is resonant and has warranted descriptions as varied as "solemn" and "terrifying". The female's call is higher and rises in pitch at the end of the call. Female vocalizations are higher in pitch because of a smaller syrinx in the larger sex. Calling seems to peak after rather than before midnight. Usually, territorial hooting decreases in February or March at the onset of egg laying. On occasion, this species exhibits "an indescribable assemblage of hoots, chuckles, screeches, and squawks, given so rapidly and disconnectedly that

5112-477: Is seen on the throat. The white throat may continue as a streak running down the middle of the breast even when the birds are not displaying, which in particularly pale individuals can widen at the belly into a large white area. South American great horned owls typically have a smaller white throat patch, often unseen unless actively displaying, and rarely display the white area on the chest. Individual and regional variations in overall color occur, with birds from

5254-565: Is sometimes attacked as prey by great horned owls, the North American porcupine ( Erethizon dorsatum ), in which average adults range from 4,500 to 9,000 g (9.9 to 19.8 lb). This has been determined from owls who have porcupine quills imbedded in them, sometimes resulting in death. On occasion, they are successful in killing porcupine, even adults as determined by the size of the quills left behind and prey remains at bloodied kill sites. Other rodents recorded as secondary prey in North America include flying squirrels ( Glaucomys ssp.),

5396-406: Is the way owls fly while making almost no discernable noise, despite their large size. This is made possible thanks to three main components of the owl's wing structure. The leading edge of their feathers have serrations that help to disrupt the turbulence generated by wing flapping, then the softer feathers help deaden the sound, and finally the trailing fringe of the feathers works to finish cutting

5538-430: Is typical in most writings. Fifteen subspecies are currently recognised: The great horned owl is generally colored for camouflage. The underparts of the species are usually light with some brown horizontal barring; the upper parts and upper wings are generally a mottled brown usually bearing heavy, complex, darker markings. All subspecies are darkly barred to some extent along the sides. A variable-sized white patch

5680-404: Is undoubtedly due to the abundance of both genera in the wooded edge habitats frequented by great horned owls. It is estimated that a family of owls with two offspring would need to take about a half dozen (voles) to a dozen (mice) of these rodents every night to satisfy their dietary requirements but apparently the accessibility and abundance of these foods is irresistible as their numeric dominance

5822-854: The Amazon rainforest . In the Appalachian Mountains , they appear to use old-growth forest but in Arkansas are actually often found near temporary agricultural openings in the midst of large areas of woodland. Similarly in south-central Pennsylvania , the owls use cropland and pasture more than deciduous and total forest cover, indicating preference for fragmented landscapes. In prairies, grasslands and deserts, they can successfully live year round as long as there are rocky canyons, steep gullies and/or wooded coulees with shade-giving trees to provide them shelter and nesting sites. In mountainous areas of North America, they are usually absent above

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5964-412: The Americas . It is an extremely adaptable bird with a vast range and is the most widely distributed true owl in the Americas. Its primary diet is rabbits and hares , rats and mice , and voles , although it freely hunts any animal it can overtake, including rodents and other small mammals, larger mid-sized mammals , birds , reptiles , amphibians , and invertebrates . In ornithological study,

6106-532: The Neotropics . Mammals (more than 200 species) and birds (nearly 300 species) make up the majority of their diet. Their diet in North America is made up of 87.6% mammals, 6.1% birds, 1.6% reptiles and amphibians with the remaining 4.7% being made up by insects, other assorted invertebrates and fish . Estimated mass of individual prey for the owls has ranged from as little as 0.4 g (0.014 oz) to as much as 6.8 kg (15 lb) Most prey

6248-607: The Rocky Mountains and to the west of them. Almost all fossils indicate these owls were larger than modern great horned owls. A large number of subspecies , more than 20 altogether, have been named. However, many of these are not true subspecies and only examples of individual or clinal variation. Subspecies differences are mainly in color and size and generally follow Gloger's and Bergmann's rules : The most conservative treatments of great horned owl subspecies may describe as few as 10, although an intermediate number

6390-439: The culmen , the exposed bill portion as measured along the top of the beak, is only 2.1 to 3.3 cm (0.83 to 1.30 in). The outer ear openings, which are concealed by feathers on the sides of the head, are relatively smaller than those of the Eurasian eagle owl, being 2.3 cm (0.91 in) in vertical axis, with the left ear slightly larger than the right. Like most exclusively (or near exclusively) nocturnal species,

6532-508: The genus Strix and coined the binomial name Strix virginia . Gmelin based his description on that of English naturalist George Edwards who had described and illustrated the great horned owl in 1747 in the second volume of his A Natural History of Uncommon Birds . Edwards had seen a live specimen from Virginia at the house of the Earl of Burlington in Chiswick . Edwards also owned

6674-416: The giant kangaroo rat ( Dipodomys ingens ) averaging at 152 g (5.4 oz), are also taken. The squirrels , including ground squirrels , marmots ( Marmota ), prairie dogs ( Cynomys ), chipmunks and tree squirrels , are diurnal and so are largely unavailable to great horned owls as prey. Occasionally though, one will be caught from their leaf nest, nest hole or burrow entrance first thing in

6816-448: The great grey owl . Great horned owls can apply at least 300 psi (2,100 kPa) of crushing power in their talons, a pressure considerably greater than the human hand is capable of exerting. In some big females, the gripping power of the great horned owl may be comparable to much larger raptor species such as the golden eagle . The hard, inflexible bill of the great horned owl is 3.3–5.2 cm (1.3–2.0 in) long, although

6958-507: The paraspecies . Overall coloration is similar, but the Magellanic is markedly smaller with smaller feet and a smaller head, with finer, but more numerous brownish bars on the underside, rather than the blotchy, irregular barring typical of great horned owls. Other eagle-owls may superficially be somewhat similar, but the species is generically allopatric with the exception of wintering snowy owls. More tropical species with ear tufts,

7100-776: The stygian owl ( A. stygius ) and striped owl ( A. clamator ), are much smaller. Other large owls lack ear tufts. The breeding habitat of the great horned owl extends high into the subarctic of North America, where they are found up to the northwestern and southern Mackenzie Mountains , Keewatin, Ontario , northern Manitoba , Fort Chimo in Ungava , Okak, Newfoundland and Labrador , Anticosti Island and Prince Edward Island . They are distributed throughout most of North America and very spottily in Central America and then down into South America south to upland regions of Argentina , Bolivia and Peru , before they give way to

7242-479: The subarctic showing a washed-out, light-buff color, while those from the Pacific Coast of North America, Central America, and much of South America can be a dark brownish color overlaid with blackish blotching. The skin of the feet and legs, though almost entirely obscured by feathers, is black. Even tropical great horned owls have feathered legs and feet. The feathers on the feet of the great horned owl are

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7384-710: The tree line , but great horned owls can be found up to 2,100 m (6,900 ft) in California and 3,300 m (10,800 ft) in the Rockies. In the Andean Mountains, on the other hand, they have adapted to being a true montane species, often found at least 3,300 m (10,800 ft) above sea level and are regularly recorded in treeless Puna grassland zones at 4,100 to 4,500 m (13,500 to 14,800 ft) in Ecuador and Peru . They are generally rare in non-tidal wetland habitat, and are replaced in

7526-770: The "Battle of the Capes", Cape Charles and Cape Henry ) in 1781, during which the French fleet defeated the Royal Navy in the decisive naval battle of the American Revolutionary War . The French victory enabled General George Washington and his French allies under the Comte de Rochambeau to march down from New York and bottle up a British army under Lord Cornwallis from the North and South Carolinas at

7668-690: The 159 g (5.6 oz) hispid cotton rat ( Sigmodon hispidus ) is the most commonly recorded prey species. The same species constituted 75% by number of a small sampling in Oklahoma . In semi-desert and other arid habitats, kangaroo rats become increasingly important prey, ten species have been reported in the diet but most prominently the Ord's and Merriam's kangaroo rats ( Dipodomys ordii & merriami ), both being widespread, numerous and relatively diminutive (at 42 and 48 g (1.5 and 1.7 oz)). Eight known larger species of kangaroo rats, including

7810-671: The Americas, its ability to colonize islands apparently being considerably less than those of barn owls and short-eared owls . Since the division into two species, the great horned owl is the second most widely distributed owl in the Americas, just after the barn owl. The great horned owl is among the world's most adaptable owls or even bird species in terms of habitat. The great horned owl can take up residence in trees that border all manner of deciduous , coniferous , and mixed forests, tropical rainforests , pampas , prairie , mountainous areas, deserts , subarctic tundra , rocky coasts, mangrove swamp forests, and some urban areas . It

7952-550: The Americas, the consensus seems to be that the snowy owl and the great horned owl divided back in Eurasia and the snowy then spread back over the Arctic through northernmost North America separately from the radiation of the greater and lesser horned owls. One older study suggested that great horned and Eurasian eagle-owls may be conspecific, based on similarities in life history, geographic distribution, and appearance, though this

8094-578: The Atlantic Ocean near Norfolk, Virginia , and the capes of Charles and Henry , there is a distinct semi-diurnal tide throughout the lunar month, with small amplitude modulations during spring (new/full moon) vs. neap (one/three quarter moon) tidal periods. The main forcing of the CBBT tides are typical, semi-diurnal ocean tides that the East Coast of the United States experiences. Baltimore, in

8236-831: The British landed on the west side of the Patuxent at Benedict, Maryland , the Chesapeake Flotilla was scuttled, and the British trekked overland to rout the U.S. Army at Bladensburg and burn the U.S. Capitol in August 1814. A few days later in a "pincer attack", they also sailed up the Potomac River to attack Fort Washington below the National Capital and raided the nearby port town of Alexandria, Virginia . There were so-called " Oyster Wars " in

8378-438: The CBBT site) this can be seen as a lowest intertidal range. Two interesting points that arise from comparing these two sites at opposite ends of the bay are their tidal characteristics - semi-diurnal tide for CBBT and mixed tide for Baltimore (due to resonance in the bay) - and the differences in amplitude (due to dissipation in the bay). The bay is well-known for its seafood, especially blue crabs , clams , and oysters . In

8520-464: The Chesapeake Bay include shad , cobia , croaker , and redfish , winter flounder , and summer flounder . Recently, non-native blue catfish have proliferated in tributaries like the James River and may be moving to other areas of the bay. A commercial fishery exists for menhaden , too oily for human consumption but instead used for bait, fish oil, and livestock feed. The Chesapeake Bay

8662-680: The Chesapeake Bay ;... I planned to spend my days boating, eating as many Chesapeake Bay blue crabs as possible and making a little study of Eastern Shore locals. For city folk like me, they're interesting, even exotic –the weather-beaten crabbers and oystermen called "watermen," gentlemen-farmers and sharecroppers, boat builders, antiques dealers – all of whom sound like Southerners with mouthfuls of marbles when they talk. — Susan Spano, Los Angeles Times , 2008 The Chesapeake Bay plays an extremely important role in Maryland, Virginia, and Pennsylvania's economies, in addition to

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8804-571: The Governor William Preston Lane, Jr. Memorial Bridge) between the state capital of Annapolis, Maryland and Matapeake on the Eastern Shore , crossing Kent Island , was constructed 1949–1952. A second, parallel, span was added in 1973. The Chesapeake Bay Bridge–Tunnel , connecting Virginia's Eastern Shore with its mainland (at the metropolitan areas of Virginia Beach , Norfolk , Portsmouth , and Chesapeake ),

8946-544: The Magellanic horned owl, which thence ranges all the way to Tierra del Fuego , the southern tip of the continent. It is absent or rare from southern Guatemala , El Salvador , Nicaragua , and Costa Rica to Panama (where only two records) in Central America and the mangrove forests of northwestern South America. The species is also absent from the West Indies , the Haida Gwaii and almost all off-shore islands in

9088-535: The Virginia landscape into what it is today. Some of the animals in these exhibits include Komodo dragons , tomistomas , spotted eagle rays , zebra shark , Egyptian cobra , hedgehog and cuttlefish . The South Building features North American river otters , a red octopus, moon jellies , and other animals. This new building gives guests behind-the-scenes access to the Vet Center, Stranding Response Program, and Water Quality Lab. The new building also includes

9230-427: The amount of nitrogen compounds entering the bay. The bay is famous for its rockfish, a regional name for striped bass . Once on the verge of extinction, rockfish have made a significant comeback because of legislative action that put a moratorium on rockfishing, which allowed the species to re-populate. Rockfish can now be fished in strictly controlled and limited quantities. Other popular recreational fisheries in

9372-518: The area now known as South Hampton Roads in the U.S. state of Virginia. They occupied an area that is now the Norfolk, Portsmouth, Chesapeake, and Virginia Beach areas. In 2005, Algonquian linguist Blair Rudes "helped to dispel one of the area's most widely held beliefs: that 'Chesapeake' means something like 'great shellfish bay'. It does not, Rudes said. The name might have actually meant something like 'great water', or it might have just referred to

9514-460: The assertion that it was as far north as the Chesapeake; most place it in present-day Georgia 's Sapelo Island . In 1573, Pedro Menéndez de Márquez , the governor of Spanish Florida, conducted further exploration of the Chesapeake. In 1570, Spanish Jesuits established the short-lived Ajacan Mission on one of the Chesapeake tributaries in present-day Virginia. The arrival of English colonists under Sir Walter Raleigh and Humphrey Gilbert in

9656-441: The bay and its tributaries, which contain sea grasses that are part of the manatee's diet. Loggerhead turtles are known to visit the bay. The Chesapeake Bay is also home to a diverse flora, both land and aquatic. Common submerged aquatic vegetation includes eelgrass and widgeon grass . A report in 2011 suggested that information on underwater grasses would be released, because "submerged grasses provide food and habitat for

9798-689: The bay at its southern point is located between Cape Henry and Cape Charles . With its northern portion in Maryland and the southern part in Virginia , the Chesapeake Bay is a very important feature for the ecology and economy of those two states, as well as others surrounding within its watershed. More than 150 major rivers and streams flow into the bay's 64,299-square-mile (166,534 km ) drainage basin , which covers parts of six states ( New York , Pennsylvania , Delaware , Maryland, Virginia, and West Virginia ) and all of Washington, D.C. The bay

9940-555: The bay at some point during the year or live there year-round. There are over 300 species of fish and numerous shellfish and crab species. Some of these include the Atlantic menhaden , striped bass , American eel , eastern oyster , Atlantic horseshoe crab , and the blue crab . Birds include ospreys , great blue herons , bald eagles , and peregrine falcons , the last two of which were threatened by DDT ; their numbers plummeted but have risen in recent years. The piping plover

10082-726: The bay between 1607 and 1609, resulting in the publication in 1612 back in the British Isles of "A Map of Virginia" . Smith wrote in his journal: "Heaven and earth have never agreed better to frame a place for man's habitation." The Captain John Smith Chesapeake National Historic Trail , the first designated "all-water" National Historic Trail in the US, was established in 2006 by the National Park Service . The trail follows

10224-432: The bay has become "emptier", with fewer crabs, oysters and watermen (fishermen) since the mid-20th century. Nutrient pollution and urban runoff have been identified as major components of impaired water quality in the bay stressing ecosystems and compounding the decline of shellfish due to overharvesting . Restoration efforts that began in the 1990s have continued into the 21st century and show potential for growth of

10366-409: The bay include the smooth dogfish , spiny dogfish , cownose ray , and bonnethead . Bottlenose dolphins are known to live seasonally/yearly in the bay. There have been unconfirmed sightings of humpback whales in recent years. Endangered North Atlantic right whale and fin , and minke and sei whales have also been sighted within and in the vicinity of the bay. A male manatee visited

10508-453: The bay several times between 1994 and 2011, even though the area is north of the species' normal range. The manatee, recognizable due to distinct markings on its body, was nicknamed "Chessie" after a legendary sea monster that was allegedly sighted in the bay during the 20th century. The same manatee has been spotted as far north as Rhode Island , and was the first manatee known to travel so far north. Other manatees are occasionally seen in

10650-736: The bay to cool its reactor. The Chesapeake Bay forms a link in the Intracoastal Waterway , of the bays, sounds and inlets between the off-shore barrier islands and the coastal mainland along the Atlantic coast connecting the Chesapeake and Delaware Canal (linking the bay to the north and the Delaware River ) with the Albemarle and Chesapeake Canal (linking the bay, to the south, via the Elizabeth River , by

10792-525: The bay's beauty: The water is glassy, smooth and gorgeous, his wake white against the deep blue. That's the problem with the Chesapeake. It's so damned beautiful. One account suggested how the Chesapeake attracts people: You see them everywhere on Maryland's Eastern Shore, the weekend sailors. They are unmistakable with their deep tans, their baggy shorts, their frayed polo shirts, their Top-Siders worn without socks. Some may not even own their own boats, much less win regattas, but they are inexorably drawn to

10934-417: The bay's dead zones were estimated to kill 75,000 tons of bottom-dwelling clams and worms each year, weakening the base of the estuary's food chain and robbing the blue crab in particular of a primary food source. Crabs are sometimes observed to amass on shore to escape pockets of oxygen-poor water, a behavior known as a "crab jubilee". Hypoxia results in part from large algal blooms , which are nourished by

11076-532: The bay, especially the Calvert County, Maryland , coastline, are lined by cliffs composed of deposits from receding waters millions of years ago. These cliffs, generally known as Calvert Cliffs , are famous for their fossils , especially fossilized shark teeth, which are commonly found washed up on the beaches next to the cliffs. Scientists' Cliffs is a beach community in Calvert County named for

11218-492: The bay. It is presumed that the Chesapeake Bay was once inhabited by Paleoindians 11,000 years ago. For thousands of years, Native American societies lived in villages of wooden longhouses close to water bodies where they fished and farmed the land. Agricultural products included beans, corn, tobacco, and squash. Villages often lasted between 10 and 20 years before being abandoned due to local resources such as firewood running out or soil depleting. To produce enough food, labor

11360-533: The bay. The salinity ranges from 1.87% to 3.6%. (3.6% is as salty as the ocean.) The climate of the area surrounding the bay is primarily humid subtropical , with hot, very humid summers and cold to mild winters. Only the area around the mouth of the Susquehanna River is continental in nature, and the mouth of the Susquehanna River and the Susquehanna flats often freeze in winter. It is rare for

11502-414: The bay. Water that was once clear for meters is now so turbid that a wader may lose sight of his feet while his knees are still dry. Great horned owl About 12, see text The great horned owl ( Bubo virginianus ), also known as the tiger owl (originally derived from early naturalists' description as the "winged tiger" or "tiger of the air") or the hoot owl , is a large owl native to

11644-862: The bones of its prey to make it more compact for carrying. On occasion, the owls may return to the kill site to continue eating if the prey is too heavy to fly with after dismemberment. Many owls will accrue a cache of prey, especially those who are nesting. Caches must be at a safe location, usually the crotch of a tall tree. In northern regions, where large prey is prevalent, an owl may let uneaten food freeze and then thaw it out later using its own body heat. Hunting success seems to require fairly open understory, and experimental testing of microhabitat proved that open areas provided more hunting success on five species of rodent, with cloudy nights and denser bush foliage both decreasing success. Prey can vary greatly based on opportunity. According to one author, "Almost any living creature that walks, crawls, flies, or swims, except

11786-558: The brown rat. Small rodents form the great majority of great horned owl prey by number. Weighing a mere 14 to 31.5 g (0.49 to 1.11 oz) and 20 to 58 g (0.71 to 2.05 oz) on average, the nine species of New World mice in Peromyscus and eight species voles in Microtus recorded in the diet would appear to be overly small to be as important as they are to a predatory bird of this size. The prominence of these genera

11928-660: The cities of Norfolk and Portsmouth to the Albemarle Sound and Pamlico Sound in North Carolina and further to the Sea Islands of Georgia). A busy shipping channel (dredged by the U.S. Army Corps of Engineers since the 1850s) runs the length of the bay, is an important transit route for large vessels entering or leaving the Port of Baltimore , and further north through the Chesapeake and Delaware Canal to

12070-886: The corvids. Typically, great horned owls are highly sedentary, often capable of utilizing a single territory throughout their mature lives. Although some species such as snowy owls, northern saw-whet owls , long-eared and short-eared owls are true migrants, most North American owls are not migratory and will generally show fidelity to a single territory year around. In great horned owls, mated pairs occupy territories year-round and long-term. Territories are established and maintained through hooting, with highest activity before egg-laying and second peak in autumn when juveniles disperse, and can range from an average of 16 km (6.2 sq mi) in Yukon to an average of 2.1 km (0.81 sq mi) in Wyoming . Most territorial defense

12212-480: The course of each river. The bay's geology, its present form, and its very location were created by a bolide impact event at the end of the Eocene (about 35.5 million years ago), forming the Chesapeake Bay impact crater and much later the Susquehanna River valley. The bay was formed starting about 10,000 years ago when rising sea levels at the end of the last ice age flooded the Susquehanna River valley. Parts of

12354-571: The depth of the bay is 21 feet (6.4 m), including tributaries; over 24 percent of the bay is less than 6 ft (2 m) deep. Because the bay is an estuary, it has fresh water, salt water and brackish water. Brackish water has three salinity zones: oligohaline, mesohaline, and polyhaline . The freshwater zone runs from the mouth of the Susquehanna River to north Baltimore . The oligohaline zone has very little salt. Salinity varies from 0.5  ppt (parts per thousand) to 10 ppt, and freshwater species can survive there. The north end of

12496-403: The desire to create a retreat for scientists when the community was founded in 1935. Much of the bay is shallow. At the point where the Susquehanna River flows into the bay, the average depth is 30 feet (9 m), although this soon diminishes to an average of 10 feet (3 m) southeast of the city of Havre de Grace, Maryland , to about 35 feet (11 m) just north of Annapolis. On average,

12638-499: The development of the skipjack (such as the Helen Virginia ), the state boat of Maryland, which is the only remaining working boat type in the United States still under sail power. Other characteristic bay-area workboats include sail-powered boats such as the log canoe , the pungy , the bugeye , and the motorized Chesapeake Bay deadrise , the state boat of Virginia. In addition to harvesting wild oysters, oyster farming

12780-912: The ecosystem. The nature-based recreation of wildlife, boating, and ecotourism are dependent on enforcement of the Clean Water Act (CWA), which regulates pollutant discharges and supports related pollution control programs. In 2006, "roughly eight million wildlife watchers spent $ 636 million, $ 960 million, and $ 1.4 billion in Maryland, Virginia, and Pennsylvania" according to the Chesapeake Bay Foundation . In colonial times, simple cooking techniques were used to create one pot meals like ham and potato casserole , clam chowder, or stews with common ingredients like oysters, chicken or venison. When John Smith landed in Chesapeake in 1608, he wrote: "The fish were so thick, we attempted to catch them with frying pans". Common regional ingredients in

12922-415: The effect is both startling and amusing". Descriptions of some of these odd sounds including a growling krrooo-ooo note pair, a laughing whar, whah, wha-a-a-a-ah , a high-pitched ank, ank, ank ; a weak, soft erk, erk , a cat -like meee-owwwwww , a hawk -like note of ke-yah, ke-yah , and a nighthawk -like peent . These vocalizations may be variously uttered when the birds are disturbed and angered at

13064-567: The entirety of the bay in about 3.3 days; by 1988 this time had increased to 325 days. The harvest's gross value decreased 88% from 1982 to 2007. One report suggested the bay had fewer oysters in 2008 than 25 years earlier. The primary problem is overharvesting . Lax government regulations allow anyone with a license to remove oysters from state-owned beds, and although limits are set, they are not strongly enforced. The overharvesting of oysters has made it difficult for them to reproduce, which requires close proximity to one another. A second cause for

13206-553: The geometry of the bay permits for a resonant period of 1.46 days. A good example of how the different Chesapeake Bay sites experience different tides can be seen in the tidal predictions published by the National Oceanographic and Atmospheric Administration (NOAA) (see figure at right). At the Chesapeake Bay Bridge–Tunnel (CBBT) site, which lies at the southernmost point of the bay where it meets

13348-423: The great horned owl has asymmetrical ear holes that allow for the triangulation of sounds when hunting in the dark. The different-height holes, while still close together, are differentiated enough that the owl is able to use the timing and direction of the sound waves hitting each hole to precisely locate prey even if the prey is located under cover such as snow. The disc-like shape of their faces also helps to direct

13490-508: The great horned owl is often compared to the Eurasian eagle-owl ( Bubo bubo ), a closely related species, which occupies the same ecological niche in Eurasia despite its notably larger size. The great horned owl is also compared to the red-tailed hawk ( Buteo jamaicensis ), with which it often shares similar habitat, prey, and nesting habits by day; thus the red-tailed hawk is something of

13632-593: The ground in pursuit of small prey or, rarely, inside a chicken coop to prey on the fowl within. Rodents and invertebrates may be caught on foot around the base of bushes, through grassy areas, and near culverts and other human structures in range and farm habitat. The great horned owl is generally a poor walker on the ground; it walks like a starling , with a pronounced side-to-side gait. They have been known to wade into shallow water for aquatic prey, although this has been only rarely reported. Owls can snatch birds and some arboreal mammals directly from tree branches in

13774-446: The habitat for much of the bay's animal life. Beds of eelgrass , the dominant variety in the southern Chesapeake Bay, have shrunk by more than half there since the early 1970s. Overharvesting, pollution, sedimentation and disease have turned much of the bay's bottom into a muddy wasteland. The principal sources of nutrient pollution in the bay are surface runoff from farms, as well as runoff from urban and suburban areas. About half of

13916-458: The help of aquarium owners, who often dump the contents of their aquariums into nearby lakes and streams. It is highly invasive and has the potential to flourish in the low-salinity tidal waters of the Chesapeake Bay. Dense stands of Brazilian waterweed can restrict water movement, trap sediment and affect water quality. Various local K-12 schools in the Maryland and Virginia region often have programs that cultivate native bay grasses and plant them in

14058-707: The high Arctic tundra by snowy owls. They prefer areas where open habitats, which they often hunt in, and woods, where they tend to roost and nest, are juxtaposed. Thus lightly populated rural regions can be ideal. This species can occasionally be found in urban or suburban areas. However, they seem to prefer areas with less human activity and are most likely to be found in park-like settings in such developed areas, unlike eastern and western screech owls ( Megascops asio & M. kennicottii ) which may regularly occur in busy suburban settings. All mated great horned owls are permanent residents of their territories, but unmated and younger birds move freely in search of company and

14200-547: The intruder continues to press the confrontation, the defending owl will "hop" forward and strike it with feet, attempting to grasp and rake with claws. Territoriality appears to place a limit on the number of breeding pairs in a given area. Individuals prevented from establishing a territory live a silent existence as "floaters". Radio-telemetry revealed that such floaters concentrate along boundaries of established territories. At Kluane Lake in Yukon , incursions into neighboring territories were observed only twice—by females when

14342-407: The large mammals, is the great horned owl's legitimate prey". In fact, the great horned owl has the most diverse prey profile of any raptor in the Americas. Over 500 species have been identified as great horned owl prey, with dozens more identified only to genus or general type (especially numerous invertebrates ) and presumably several more unknown from their relatively little-studied populations in

14484-428: The largest eyes of all terrestrial vertebrates. The great horned owl has cylindrical eyes which creates more distance from the lens of the eye to the retina, which allows it to act more like a telephoto lens for farther distance sight compared to that possible from round eyes. They are visually highly adapted for nocturnal hunting and provide a wide, almost completely binocular field of view, a large corneal surface and

14626-583: The late 16th century to found a colony, later settled at Roanoke Island (off the present-day coast of North Carolina ) for the Virginia Company , marked the first time that the English approached the gates to the Chesapeake Bay between the capes of Cape Charles and Cape Henry . Three decades later, in 1607, Europeans again entered the bay. Captain John Smith of England explored and mapped

14768-587: The late 19th and early 20th centuries. Until the mid-20th century, oyster harvesting rivaled the crab industry among Chesapeake watermen, a dwindling breed whose skipjacks and other workboats were supplanted by recreational craft in the latter part of the century. In the 1960s, the Calvert Cliffs Nuclear Power Plant on the historic Calvert Cliffs in Calvert County on the Western Shore of Maryland began using water from

14910-540: The leadership of a central chief. In 1524, Italian explorer Giovanni da Verrazzano , (1485–1528), in service of the French crown , (famous for sailing through and thereafter naming the entrance to New York Bay as the " Verrazzano Narrows ", including now in the 20th century, a suspension bridge also named for him ) sailed past the Chesapeake, but did not enter the bay. Spanish explorer Lucas Vásquez de Ayllón sent an expedition out from Hispaniola in 1525 that reached

15052-450: The local cuisine of Chesapeake included terrapins , smoked hams, blue crab, shellfish, local fish, game meats and various species of waterfowl. Blue crab continues to be an especially popular regional specialty. In the 1970s, the Chesapeake Bay was found to contain one of the planet's first identified marine dead zones , where waters were so depleted of oxygen that they were unable to support life, resulting in massive fish kills . In 2010

15194-544: The marine ecosystem. The word Chesepiooc is an Algonquian word referring to a village 'at a big river'. It is the seventh-oldest surviving English placename in the United States, first applied as Chesepiook by explorers heading north from the Roanoke Colony into a Chesapeake tributary in 1585 or 1586. The name may also refer to the Chesapeake people or the Chesepian, a Native American tribe who inhabited

15336-416: The measured wing area compared to weight, is high, meaning the wings are relatively small in surface area for the bird's weight; the species' wing loading has been described as proportionately the highest among raptors. The tail , being relatively short as is typical of most owls, is 175 to 252 mm (6.9 to 9.9 in) long. Like other owl species, the great horned owl is capable of "silent flight", which

15478-472: The middle of the 20th century, the bay supported 9,000 full-time watermen, according to one account. Today, the body of water is less productive than it used to be because of runoff from urban areas (mostly on the Western Shore) and farms (especially on the Eastern Shore and in the Susquehanna River watershed), over-harvesting, and invasion of foreign species . The plentiful oyster harvests led to

15620-408: The moment there is a crow on exhibit, with others off exhibit but used for educational programs. There are no current plans to rebuild the aviary. The Adventure Park at the Virginia Aquarium is an outdoor rope-climbing center, described as Virginia Beach's "largest and most exciting adventure park." It features over 250 elements, as well as over 30 ziplines , the longest one running over 300 feet over

15762-425: The morning or in the late afternoon and approximately 35 species have been successfully predated by these owls. In general larger sized than other rodent families, the species hunting range from the 62 g (2.2 oz) gray-collared chipmunk ( Tamias cinereicollis ) to the 5,775 g (12.732 lb) hoary marmot ( Marmota caligata ); thus, squirrels can provide a very fulfilling meal. An even larger rodent

15904-522: The mouths of the Chesapeake and Delaware Bays . It may have been the first European expedition to explore parts of the Chesapeake Bay, which the Spaniards called "Bahía de Santa María" ("Bay of St. Mary") or "Bahía de Madre de Dios."("Bay of the Mother of God") De Ayllón established a short-lived Spanish mission settlement, San Miguel de Gualdape , in 1526 along the Atlantic coast . Many scholars doubt

16046-414: The native oyster population. The health of the Chesapeake Bay improved in 2015, marking three years of gains over a four-year period. Slight improvements in water quality were observed in 2021, compared to indicators measured in 2020. The bay is experiencing other environmental concerns, including climate change which is causing sea level rise that erodes coastal areas and infrastructure and changes to

16188-591: The nature of the topography (both horizontal and vertical shape), wind-driven circulation, and how the bay interacts with oceanic tides. Research into the peculiar behavior of tides both at the northern and southern extents of the bay began in the late 1970s. One study noted sea level fluctuations at periods of 5 days, driven by sea level changes at the bay's mouth on the Atlantic coast and local lateral winds, and 2.5 days, caused by resonant oscillations driven by local longitudinal winds, while another study later found that

16330-549: The nearby creek. Chesapeake Bay The Chesapeake Bay ( / ˈ tʃ ɛ s ə p iː k / CHESS -ə-peek ) is the largest estuary in the United States. The bay is located in the Mid-Atlantic region and is primarily separated from the Atlantic Ocean by the Delmarva Peninsula , including parts of the Eastern Shore of Maryland , the Eastern Shore of Virginia , and the state of Delaware . The mouth of

16472-1124: The nest (frequently preceding an attack on an interloping human or other animal), represent the vocal development of young owls, or are given during courtship and during territorial disputes with other owls. Young owls still in the care of their parents make loud, persistent hissing or loud, piercing screeching sounds that are often confused with the calls of the barn owl. Common/eastern great horned owl ( Bubo virginianus virginianus ) South American great horned owl ( Bubo virginianus nacurutu ) Northern/sub-Arctic great horned owl ( Bubo virginianus subarcticus ) California great horned owl ( Bubo virginianus pacificus ) Coastal great horned owl ( Bubo virginianus saturatus ) North Andean great horned owl ( Bubo virginianus nigrescens ) Desert great horned owl ( Bubo virginianus pallescens ) Yucatán great horned owl ( Bubo virginianus mayensis ) Baja California great horned owl ( Bubo virginianus elachistus ) Northeastern great horned owl ( Bubo virginianus heterocnemis ) Rocky Mountains great horned owl ( Bubo virginianus pinorum ) The combination of

16614-407: The northern portion of the bay, experiences a noticeable modulation to form its mixed tidal nature during spring vs. neap tides. Spring tides, when the sun-earth-moon system forms a line, cause the largest tidal amplitudes during lunar monthly tidal variations. In contrast, neap tides, when the sun-earth-moon system forms a right angle, are muted, and in a semi-diurnal tidal system (such as that seen at

16756-665: The northern weighs from 90 to 120 g (3.2 to 4.2 oz), other pocket gophers hunted average from 95 to 545 g (0.209 to 1.202 lb) in mass. From Washington to Baja California a very important food is the pocket mice , primarily the Great Basin pocket mouse ( Perognathus parvus ). While the Great Basin species is a relative giant at 22 g (0.78 oz), other hunted pocket mice (which may include both Perognathus and Chaetodipus ssp.) can average nearly as light as 8 g (0.28 oz). In East Texas ,

16898-409: The northernmost point on the bay. North of Baltimore , the western shore borders the hilly Piedmont region of Maryland; south of the city the bay lies within the state's low-lying coastal plain , with sedimentary cliffs to the west, and flat islands, winding creeks and marshes to the east. The large rivers entering the bay from the west have broad mouths and are extensions of the main ria for miles up

17040-515: The number of species displayed by the aquarium. Some of the new animals include Komodo dragons , tomistomas , spotted eagle rays , and cuttlefish . The two main exhibit buildings of the aquarium are the Bay and Main Building and South Building. The two are connected by a one-third mile outdoor nature trail running alongside Owls Creek Salt Marsh. The area also contains the Adventure Park,

17182-536: The nutrient pollutant loads in the bay are generated by manure and poultry litter. Extensive use of lawn fertilizers and air pollution from motor vehicles and power plants are also significant nutrient sources. One particularly harmful source of toxicity is Pfiesteria piscicida , which can affect both fish and humans. Pfiesteria caused a small regional panic in the late 1990s when a series of large blooms started killing large numbers of fish while giving swimmers mysterious rashes; nutrient runoff from chicken farms

17324-411: The nutrients phosphorus and nitrogen . The algae prevents sunlight from reaching the bottom of the bay while alive and deoxygenates the bay's water when it dies and rots. Soil erosion and runoff of sediment into the bay, exacerbated by devegetation, construction and the prevalence of pavement in urban and suburban areas, also block vital sunlight. The resulting loss of aquatic vegetation has depleted

17466-676: The oligohaline zone is north Baltimore and the south end is the Chesapeake Bay Bridge. The mesohaline zone has a medium amount of salt and runs from the Bay Bridge to the mouth of the Rappahannock River . Salinity there ranges from 1.07% to 1.8%. The polyhaline zone is the saltiest zone, and some of the water can be as salty as sea water. It runs from the mouth of the Rappahannock River to the mouth of

17608-403: The oyster depletion is that the drastic increase in human population caused a sharp increase in pollution flowing into the bay. The bay's oyster industry has also suffered from two diseases: MSX and Dermo . The depletion of oysters has had a particularly harmful effect on the quality of the bay. Oysters serve as natural water filters, and their decline has further reduced the water quality of

17750-517: The ports of Wilmington and Philadelphia on the Delaware River . During the later half of the 19th century and the first half of the 20th century, the bay was plied by passenger steamships and packet boat lines connecting the various cities on it, notably the Baltimore Steam Packet Company ("Old Bay Line"). In the later 20th century, a series of road crossings were built. One, the Chesapeake Bay Bridge (also known as

17892-531: The route of Smith's historic 17th-century voyage. Because of economic hardships and civil strife in the "Mother Land", there was a mass migration of southern English Cavaliers and their servants to the Chesapeake Bay region between 1640 and 1675, to both of the new colonies of the Province of Virginia and the Province of Maryland . The Chesapeake Bay was the site of the Battle of the Chesapeake (also known as

18034-562: The runoff of residential, farm and industrial waste throughout the watershed. A 2010 report criticized Amish farmers in Pennsylvania for raising cows with inadequate controls on the manure that they generate. Farms in Lancaster County, Pennsylvania generate large quantities of manure that washes into tributaries of the bay. The pollution entering the bay has multiple components that contribute to algal blooms, principally

18176-518: The same location where the prey was consumed. Great horned owl pellets are dark gray or brown in color and very large, 7.6 to 10.2 cm (3.0 to 4.0 in) long and 3.8 cm (1.5 in) thick, and have been known to contain skulls up to 3 cm (1.2 in) in width inside them. However, not all prey can be swallowed at once, and owls will also fly with prey to a perch and tear off pieces with their bill. Most dietary studies focus on pellets found under perches and around nests, since they provide

18318-435: The second-longest known in any owl (after the snowy owl ). The bill is dark gunmetal-gray, as are the talons. All great horned owls have a facial disc . This can be reddish, brown, or gray in color (depending on geographical and racial variation) and is demarked by a dark rim culminating in bold, blackish side brackets. This species' eyebrow-like "horns" are tufts of feathers , called plumicorns. The purpose of plumicorns

18460-623: The siege of Battle of Yorktown in Yorktown, Virginia . Their marching route from Newport, Rhode Island through Connecticut, New York State, Pennsylvania, New Jersey and Delaware to the "Head of Elk" by the Susquehanna River along the shores and also partially sailing down the bay to Virginia . It is also the subject of a designated National Historic Trail as the Washington–Rochambeau Revolutionary Route . The bay would again see conflict during War of 1812 . During

18602-559: The sounds made by flight. The structure of the great horned owl wing also allows it to fly at a very low speed for the size of the species, as slow as 2 miles per hour when they are gliding on breezes. The legs, feet, and talons are large and powerful. Tarsal length is 54–80 mm (2.1–3.1 in). The average foot span of a fully spread foot, from talon to talon, is around 20 cm (7.9 in), as compared to 8 cm (3.1 in) in long-eared owls , 13 to 15 cm (5.1 to 5.9 in) in barn owls , and 18 cm (7.1 in) in

18744-450: The sounds they hear toward their ears. While the true nature/purpose of the ear tufts that are present on the great horned owl is unknown, researchers agree that the tufts do not play any role in the hearing ability of the owl. It is estimated that their hearing is up to ten times that of a human being. The great horned owl's eyes, just slightly smaller than the eyes of a human being , are large even for an owl and rank proportionately among

18886-417: The species' bulk, prominent ear tufts and barred plumage distinguishes it through much of the range, but it may be easily confused with the lesser horned owl ( B. magellanicus ), which may overlap in range. The Magellanic horned owl was once considered a subspecies of the great horned, but is now almost universally considered a distinct species, as is supported by genetic materials, with the great horned being

19028-470: The surface of the bay to freeze in winter, something that happened most recently in the winter of 1976–77. The Chesapeake Bay is the end point of over 150 rivers and streams. The largest rivers flowing directly into the bay, in order of discharge, are: For more information on Chesapeake Bay rivers, see the List of Chesapeake Bay rivers . The Chesapeake Bay is home to numerous fauna that either migrate to

19170-466: The tall-thin position. Outside of the nesting season, great horned owls may roost wherever their foraging path ends at dawn. Generally great horned owls are active at night, although in some areas they may be active in the late afternoon or early morning. At dusk, the owl utters a few calls before flying to a more open sing-post, i.e. large bare branch or large rocks to deliver song. Normally several perches are used to mark occupied territory or to attract

19312-644: The timbered fringes of garbage or refuse dumps may subsist mostly on rats. In the Rockies , California, the Southwestern United States and northern Mexico , the diversity of this species' diet rises, in sync with the diversity of rodents. Especially important, from Colorado to Washington state is the northern pocket gopher ( Thomomys talpoides ), although assorted other pocket gophers ( Geomys , Cratogeomys , Zygogeomys , Pappogeomys and other Thomomys ssp.) are readily taken. While

19454-468: The wing, they also sometimes hunt by flying low over openings on the ground, scanning below for prey activity. Great horned owls can fly at speeds of more than 65 km/h (40 mph) in level flight. Hunting flights are slow, often quartering low above the ground where prey is likely to occur in open country or open woodland. Brief hovering flight (for about 6–18 seconds) has been described, especially in windy areas. On occasion owls may actually walk on

19596-448: The year of 1813, from their base on Tangier Island , British naval forces under the command of Admiral George Cockburn raided several towns on the shores of the Chesapeake, treating the bay as if it were a "British Lake". The Chesapeake Bay Flotilla , a fleet of shallow-draft armed barges under the command of U.S. Navy Commodore Joshua Barney , was assembled to stall British shore raids and attacks. After months of harassment by Barney,

19738-507: The year. Typically, males have a favorite roosting site not far from the nest, sometimes used over successive years. While roosting, great horned owls may rest in the "tall-thin" position, where they sit as erect and hold themselves as slim as is possible. The kind of posture is well known as a further method of camouflage for other owls, like long-eared owls or great grey owls, especially if humans or other potential mammalian carnivores approach them. The Eurasian eagle owl rarely, if ever, assumes

19880-566: Was a half-acre habitat located behind the March Pavilion, and was home to 70 birds of about 30 species including a great horned owl , turkey vultures , great blue herons , brown pelicans , fulvous whistling duck , great egrets , and ruddy ducks . Many of the birds had been injured and rehabilitated, and could not be released back into the wild. The aviary was badly damaged by a storm in the winter of 2015; though no birds were killed, most had to be dispersed to other wildlife centers. At

20022-409: Was blamed for the growth. While the bay's salinity is ideal for oysters and the oyster fishery was at one time the bay's most commercially viable, the population has in the last fifty years been devastated. Maryland once had roughly 200,000 acres (810 km ) of oyster reefs. In 2008 there were about 36,000 acres (150 km ). It has been estimated that in pre-colonial times, oysters could filter

20164-576: Was divided with men hunting while the women supervised the village's farming. All village members took part in the harvesting of fish and shellfish from the local bodies of water. As time went on, communities around the Chesapeake Bay formed confederations such as the Powhatan , the Piscataway , and the Nanticoke . Each of these confederations consisted of a collection of smaller tribes falling under

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