Hunting success depends on the skills of individual birds, weather, and water conditions like the tide in coastal areas. Still, dives are quite successful.
At the lower end, 1 in 4 dives will result in catching a fish. In ideal conditions, ospreys will catch a fish 3 out of 4 times. Since they rely on fish as the main source of their diet, ospreys are closely associated with water. They fish in both fresh and salt water; hence they can be found near rivers, lakes, large stream, reservoirs, coastal estuaries, salt marches, and ocean shores.
H umans and wildlife are intricately connected to each other and to the earth, which we all share. Our ability to manipulate the environment to seemingly better suit our needs, and the close connection human actions have with wildlife populations, presents us with a great responsibility and unique challenge.
The effect of human actions on wildlife became clearly evident in the s and s when populations of ospreys and other raptors, including eagles, brown pelicans and peregrine falcons, in the United States dramatically plummeted to nearly unrecoverable low levels.
Scientists linked the population declines to the widespread use of DDT dichlorodiphenyltrichloroethane as a pesticide. To reduce insect damage and enhance productivity, agricultural crops across the country were sprayed with DDT.
Water runoff from snowmelt, rain and irrigation carried the deadly chemical into water systems where fish and other aquatic organisms were poisoned. Also, contaminated insects and plants were eaten by fish and small birds, thus passing the poison directly to them. Those fish and birds were then eaten by raptors, which accumulated the chemical in their bodies. The accumulation of chemicals in organisms in increasingly higher concentrations at successive trophic levels, or higher steps in a food chain, is called biomagnification.
Scientists found that DDT accumulates in the fatty tissues of birds, mammals and fish and that it passes through food chains. In other words, in the case of ospreys, the birds fed on large quantities of fish, which had eaten insects. Since ospreys can live almost anywhere there is shallow unfrozen water with safe nesting sites and plenty of fish, it's no wonder that ospreys are found on every continent except Antarctica.
Ospreys that breed near water that freeze in winter, such as in the norther latitudes of the Northern Hemisphere, migrate in the spring to their summer breeding habitats and return to southern waters during the winters. Only occasionally, when fish aren't available, will the Osprey eat small mammals, birds, or reptiles.
However, the Osprey is highly specialized for eating fish and does not stray from this diet unless necessary. When it catches a fish, the Osprey usually flies with it held headfirst. Ospreys build large nests near water, on top of dead trees or artificial structures that are similar to dead trees, such as utility or nesting poles. Nests are made of branches, sticks, and twigs, lined with smaller twigs, grasses, bark, moss, fish bones, and other material. They will reuse nests year after year and continue to add sticks each year, ending up with a huge nest.
Nests may be more than seven feet across and over five feet deep. The female typically lays 3 eggs, although clutch sizes between 2 and 4 eggs are normal. Both members of the pair incubate the eggs for days. After the young hatch, the female stays with them, and the male brings food.
Once the young can be left alone, both parents provide food. The young do not fledge until they are days old. Ospreys are migratory, the majority wintering south of the US border. Most reports of Ospreys wintering in Washington are likely to be misidentifications of sub-adult bald eagles. The Osprey suffered great declines in the past century as a result of DDT and other eggshell-thinning pesticides.
Range expansion into formerly occupied areas has been slow due to their strong philopatry to nesting areas. Artificial nest platforms have significantly increased nesting in many areas. Ospreys are found in a variety of freshwater, brackish and marine environments.
Habitat The most important habitat requirement is the presence of large watercourses such as rivers, lakes or coastal areas. Clean unpolluted water is highly beneficial to them. Feeding behaviour The osprey is a specialist feeder, relying on medium-sized fish, both marine and fresh-water.
Share this page Facebook Facebook Created with Sketch. Twitter Pinterest. You might also be interested in. Nesting and breeding habits. Protecting Birds of Prey. Population trends. But what makes them different to other reptiles is that turtles have a shell. This shell, composed of a carapace in the back and a plastron on the belly, is made of bony plates. These bones are covered by horny scutes made of keratin like human fingernails or leathery skin, depending on the species.
All Canadian freshwater turtles can retreat in their shells and hide their entire body except the Common Snapping Turtle Chelydra serpentina. This shell is considered perhaps the most efficient form of armour in the animal kingdom, as adult turtles are very likely to survive from one year to the next.
Indeed, turtles have an impressively long life for such small animals. Most other species can live for more than 20 years. There are about species of turtles throughout the world, inhabiting a great variety of terrestrial, freshwater and marine ecosystems on every continent except Antarctica and its waters.
In Canada, eight native species of freshwater turtles and four species of marine turtles can be observed. Another species, the Pacific Pond Turtle Clemmys marmorata , is now Extirpated, having disappeared from its Canadian range.
Also, the Eastern Box Turtle Terrapene carolina has either such a small population that it is nearly Extirpated, or the few individuals found in Canada are actually pets released in the wild. More research is needed to know if these turtles are still native individuals. Finally, the Red-eared Slider Trachemys scripta elegans , has been introduced to Canada as released pets and, thus, is not a native species.
Females tend to be slightly larger than males but are otherwise identical. As its name implies, it is pale tan to reddish or dark brown with a slightly paler belly, and ears and wings that are dark brown to black.
Contrary to popular belief, Little Brown Bats, like all other bats, are not blind. Still, since they are nocturnal and must navigate in the darkness, they are one of the few terrestrial mammals that use echolocation to gather information on their surroundings and where prey are situated. The echolocation calls they make, similar to clicking noises, bounce off objects and this echo is processed by the bat to get the information they need.
These noises are at a very high frequency, and so cannot be heard by humans. Narwhals Monodon monoceros are considered medium-sized odontocetes, or toothed whales the largest being the sperm whale, and the smallest, the harbour porpoise , being of a similar size to the beluga, its close relative. Males can grow up to 6. Females tend to be smaller, with an average size of 4 m and a maximum size of 5. A newborn calf is about 1. Like belugas, they have a small head, a stocky body and short, round flippers.
Narwhals lack a dorsal fin on their backs, but they do have a dorsal ridge about 5 cm high that covers about half their backs. This ridge can be used by researchers to differentiate one narwhal from another. It is thought that the absence of dorsal fin actually helps the narwhal navigate among sea ice. Unlike other cetaceans —the order which comprises all whales—, narwhals have convex tail flukes, or tail fins. These whales have a mottled black and white, grey or brownish back, but the rest of the body mainly its underside is white.
Newborn narwhal calves are pale grey to light brownish, developing the adult darker colouring at about 4 years old. As they grow older, they will progressively become paler again.
Some may live up to years, but most probably live to be 60 years of age. Although the second, smaller incisor tooth often remains embedded in the skull, it rarely but on occasion develops into a second tusk. Tusks typically grow only on males, but a few females have also been observed with short tusks. The function of the tusk remains a mystery, but several hypotheses have been proposed. Many experts believe that it is a secondary sexual character, similar to deer antlers.
Thus, the length of the tusk may indicate social rank through dominance hierarchies and assist in competition for access to females. Indeed, there are indications that the tusks are used by male narwhals for fighting each other or perhaps other species, like the beluga or killer whale.
A high quantity of tubules and nerve endings in the pulp —the soft tissue inside teeth — of the tusk have at least one scientist thinking that it could be a highly sensitive sensory organ, able to detect subtle changes in temperature, salinity or pressure.
Narwhals have not been observed using their tusk to break sea ice, despite popular belief. Narwhals do occasionally break the tip of their tusk though which can never be repaired. This is more often seen in old animals and gives more evidence that the tusk might be used for sexual competition. Adult coho salmon have silvery sides and metallic blue backs with irregular black spots. Spawning males have bright red sides, and bright green backs and heads, with darker colouration on their bellies. The fish have hooked jaws and sharp teeth.
Young coho salmon are aggressive, territorial and often vibrantly coloured, with a large orange anal fin edged in black and white. Ptarmigans are hardy members of the grouse family that spend most of their lives on the ground at or above the treeline. Like other grouse, ptarmigans have chunky bodies, short tails and legs, and short, rounded wings. Willow Ptarmigans weigh from to g, White-tailed Ptarmigans weigh about g, and Rock Ptarmigans are intermediate in size. All ptarmigans have feathered feet, unique among chickenlike birds, which improve their ability to walk in snow.
They also have white wings throughout the year. Inflatable red combs above their eyes, which are especially evident in territorial and courting males, are inconspicuous to barely visible in females.
Ptarmigans have three seasonal plumages per year, instead of the two that are usual for most birds. These plumages keep the birds, particularly the female, well camouflaged at all times. In winter, all ptarmigans of both sexes are basically white.
Whereas White-tailed Ptarmigans have permanently white tail feathers, the tails of Willow and Rock Ptarmigans remain black throughout the year. In winter, male—and some female—Rock Ptarmigans sport a black stripe that extends through the eye to the bill as if they had put on charcoal goggles to prevent snow blindness , distinguishing them from male Willow Ptarmigans.
In ptarmigans, the moult, or shedding of old feathers, starts with the head and progresses towards the tail. As soon as the spring snowmelt begins, females moult into a barred breeding plumage of brown, gold, and black. Female ptarmigans are difficult to tell apart in spring, but the overall tones of the White-tailed Ptarmigan females are cooler in comparison to those of the other two species.
Breeding males delay their moult. The Roseate Tern Sterna dougallii is a seabird that resembles a small gull, but it has the typically slender body, short legs, and long, pointed wings of all terns. It is closely related to the Common Tern Sterna hirundo and the Arctic Tern Sterna paradisaea and is frequently found in their company. For these reasons, the Roseate Tern is not easy to identify see drawings. It is a paler grey than Arctic and Common terns, and its tail streamers are considerably longer.
The adult Roseate Tern is 33 to 34 cm in length and has a wingspan of 72 to 80 cm. At a weight of approximately to g, an adult is slightly smaller than a Mourning Dove. It has a black forehead and nape, and its upper wing is a pale grey. Its tail is white with deeply forked outer feathers that give the impression of long streamers when the bird is in flight.
The underside of the tern is white, tinged with pink early in the breeding season; however, this pale rosy tint is not a good field mark, or identification characteristic, because it varies from bird to bird, and the colour tends to be bleached out by the sun. The legs and feet are reddish, and the bill is mostly black, although bills of breeding birds may be red at the base.
Male and female birds look alike. The head of the nonbreeding adult is mottled black and white. The juvenile Roseate Tern has a mottled greyish back and rump and dark bill and legs. Chicks are unevenly covered with down, giving them a spiky appearance; their legs are dark purplish to black. Signs and sounds All terns have a harsh cry, but the Roseate Tern has a distinctive, two-syllable call — kir-rick. This is often the best way of confirming its presence at a colony.
Many naturalists and hunters consider the Wood Duck Aix sponsa to be the most beautiful duck in North America, if not the world. The male in its multi-coloured breeding plumage, worn from October through June, is unexcelled among ducks. The female is less showy, although still beautiful and more colourful than other female ducks. Wood Ducks are intermediate in size, between the Mallard and Blue-winged Teal; on average, males weigh g and females weigh g.
From a distance, the male Wood Duck on the water appears as a dark-bodied, dark-breasted, light-flanked duck with a striped crested head and a light-coloured throat. At close range, its iridescent plumage, red eyes, and black, red, and white bill are conspicuous. A white eye-ring, light-coloured throat, and fine crest distinguish the female from both the male Wood Duck and females of other species.
Both sexes usually show a downward pointing crest at the back of the head, and their long broad square tails are distinctive features in flight. The wings of Wood Ducks are highly characteristic. The primary wing feathers, which are the 10 outermost flight feathers attached to the wing beyond the wrist, are dark in colour.
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