When do purple martins come

Their belly is generally yellow-white to light green. Males are slightly smaller than females, but the surest way to tell sexes apart is by the fact that only males call and can inflate their yellow vocal sacs. Adults tend to live only for one year, but some have lived as many as three years.

Their tadpoles the life stage between the egg and the adult are grey or brown. Their body is round with a clear tail. The Common Raven Corvus corax is one of the heaviest passerine birds and the largest of all the songbirds. It is easily recognizable because of its size between 54 and 67 centimetres long, with a wingspan of to cm, and weighing between 0. It has a ruff of feathers on the throat, which are called 'hackles', and a wide, robust bill.

When in flight, it has a wedge-shaped tail, with longer feathers in the middle. While females may be a bit smaller, both sexes are very similar. The size of an adult raven may also vary according to its habitat, as subspecies from colder areas are often larger.

A raven may live up to 21 years in the wild, making it one of the species with the longest lifespan in all passerine birds. Both birds are from the same genus order of passerine birds, corvid family —like jays, magpies and nutcrackers, Corvus genus and have a similar colouring. But the American Crow is smaller with a wingspan of about 75 cm and has a fan-shaped tail when in flight with no longer feathers.

Their cries are different: the raven produces a low croaking sound, while the crow has a higher pitched cawing cry. While adult ravens tend to live alone or in pairs, crows are more often observed in larger groups. The Atlantic Cod Gadus morhua is a medium to large saltwater fish: generally averaging two to three kilograms in weight and about 65 to centimetres in length, the largest cod on record weighed about kg and was more than cm long! Individuals living closer to shore tend to be smaller than their offshore relatives, but male and female cod are not different in size, wherever they live.

The Atlantic Cod shares some of its physical features with the two other species of its genus, or group of species, named Gadus. The Pacific Cod and Alaska Pollock also have three rounded dorsal fins and two anal fins.

They also have small pelvic fins right under their gills, and barbels or whiskers on their chins. Both Pacific and Atlantic Cod have a white line on each side of their bodies from the gills to their tails, or pectoral fins. This line is actually a sensory organ that helps fish detect vibrations in the water.

The colour of an Atlantic Cod is often darker on its top than on its belly, which is silver, white or cream-coloured. In rocky areas, a cod may be a darker brown colour. Cod are often mottled, or have a lot of darker blotches or spots. It can weigh up to 63, kilograms and measure up to 16 metres. Females tend to be a bit larger than males — measuring, on average, one metre longer.

Its head makes up about a fourth of its body length, and its mouth is characterized by its arched, or highly curved, jaw. Its skin is otherwise smooth and black, but some individuals have white patches on their bellies and chin.

It has large, triangular flippers, or pectoral fins. Its tail, also called flukes or caudal fins, is broad six m wide from tip to tip! Unlike most other large whales, it has no dorsal fin. For a variety of reasons, including its rarity, scientists know very little about this rather large animal.

For example, there is little data on the longevity of Right Whales, but photo identification on living whales and the analysis of ear bones and eyes on dead individuals can be used to estimate age. It is believed that they live at least 70 years, maybe even over years, since closely related species can live as long.

Unique characteristics. The Right Whale has a bit of an unusual name. Its name in French is more straightforward; baleine noire, the black whale. The American Eel Anguilla rostrata is a fascinating migratory fish with a very complex life cycle. Like salmon, it lives both in freshwater and saltwater. It is born in saltwater and migrating to freshwater to grow and mature before returning to saltwater to spawn and die.

The American Eel can live as long as 50 years. It is a long, slender fish that can grow longer than one metre in length and 7. Males tend to be smaller than females, reaching a size of about 0. With its small pectoral fins right behind its gills, absence of pelvic fins, long dorsal and ventral fins and the thin coat of mucus on its tiny scales, the adult eel slightly resembles a slimy snake but are in fact true fish. Adult eels vary in coloration, from olive green and brown to greenish-yellow, with a light gray or white belly.

Females are lighter in colour than males. Large females turn dark grey or silver when they mature. The American Eel is the only representative of its genus or group of related species in North America, but it does have a close relative which shares the same spawning area: the European Eel. Both have similar lifecycles but different distributions in freshwater systems except in Iceland, where both and hybrids of both species can be found. The American Lobster Homarus americanus is a marine invertebrate which inhabits our Atlantic coastal waters.

As an invertebrate, it lacks bones, but it does have an external shell, or exoskeleton, making it an arthropod like spiders and insects. Its body is divided in two parts: the cephalothorax its head and body and its abdomen, or tail. On its head, the lobster has eyes that are very sensitive to movement and light, which help it to spot predators and prey, but are unable to see colours and clear images.

It also has three pairs of antennae, a large one and two smaller ones, which are its main sensory organs and act a bit like our nose and fingers. Around its mouth are small appendages called maxillipeds and mandibles which help direct food to the mouth and chew. Lobsters have ten legs, making them decapod ten-legged crustaceans, a group to which shrimp and crabs also belong other arthropods have a different number of legs, like spiders, which have eight, and insects, which have six.

Four pairs of these legs are used mainly to walk and are called pereiopods. The remaining pair, at the front of the cephalothorax, are called chelipeds and each of those limbs ends with a claw.

These claws help the lobster defend itself, but also capture and consume its prey. Each claw serves a different purpose: the bigger, blunter one is used for crushing, and the smaller one with sharper edges, for cutting.

The Barn Swallow Hirundo rustica is a medium-sized songbird, about the size of a sparrow. It measures between 15 and 18 centimeters cm in length and 29 to 32 cm in wingspan, and weighs between 15 and 20 grams g. Its back and tail plumage is a distinctive steely, iridescent blue, with light brown or rust belly and a chestnut-coloured throat and forehead. Their long forked tail and pointed wings also make them easily recognizable. Both sexes may look similar, but females are typically not as brightly coloured and have shorter tails than males.

When perched, this swallow looks almost conical because of its flat, short head, very short neck and its long body. Although the average lifespan of a Barn Swallow is about four years, a North American individual older than eight years and a European individual older than 16 years have been observed.

Sights and sounds: Like all swallows, the Barn Swallow is diurnal —it is active during the day, from dusk to dawn. It is an agile flyer that creates very acrobatic patterns in flight. It can fly from very close to the ground or water to more than 30 m heights. When not in flight, the Barn Swallow can be observed perched on fences, wires, TV antennas or dead branches. Both male and female Barn Swallows sing both individually and in groups in a wide variety of twitters, warbles, whirrs and chirps.

They give a loud call when threatened, to which other swallows will react, leaving their nests to defend the area. Freshwater turtles are reptiles, like snakes, crocodilians and lizards.

They also have a scaly skin, enabling them, as opposed to most amphibians, to live outside of water. Also like many reptile species, turtles lay eggs they are oviparous.

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.

The scientific name for the Ruffed Grouse is Bonasa umbellus. Both terms are from the Latin: Bonasa means good when roasted and umbellus , a sunshade. Nest may have raised dirt rim in front to help keep eggs from rolling out. Learn more about these drawings. A long-distance migrant, most wintering in Amazon Basin. Returns very early in spring in the east often in February in southern states , usually later in spring in the west mainly April and May. Choose a temperature scenario below to see which threats will affect this species as warming increases.

The same climate change-driven threats that put birds at risk will affect other wildlife and people, too. Purple Martins exposed to bright nighttime light migrated eight days early—which could lead to starvation at their breeding grounds. The legislation helps the agriculture and forestry industries naturally remove carbon from the atmosphere, creating a cleaner future for birds and people. Alisa Esposito made it her mission to protect Purple Martins from deadly collisions on a North Carolina bridge.

When personal tragedy struck, the birds helped her through the ordeal. Latin: Riparia riparia. Latin: Hirundo rustica. Latin: Petrochelidon fulva. Latin: Petrochelidon pyrrhonota. Latin: Sturnus vulgaris. Latin: Stelgidopteryx serripennis.

Latin: Tachycineta bicolor. Latin: Tachycineta thalassina. Membership benefits include one year of Audubon magazine and the latest on birds and their habitats. Your support helps secure a future for birds at risk. Our email newsletter shares the latest programs and initiatives. Graceful in flight, musical in its pre-dawn singing, this big swallow is one of our most popular birds. Almost all Purple Martins in the east now nest in birdhouses put up especially for them.

Martin housing has a long history: some Native American tribes reportedly hung up hollow gourds around their villages to attract these birds.

Purple Martins migrate to South America for the winter, but before leaving, they may gather to roost in groups of thousands in late summer.

Thirteen ways martins are unique. The breeding range, wintering range, northward migration pathways, and arrival schedule of the Purple Martin.

Johnston, R. Behavior of the Purple Martin. Wilson Bull. Peterjohn, B. Trends and abundance patterns in the Purple Martin: results from the North American breeding bird survey, Ray, J. Purple Martins in northwest Texas. The Purple Martin and its management in Texas. Second edition. Texas Parks and Wildl. Tree-nesting Purple Martins in northeastern New Mexico. Purple Martin Update 9 2 Sauer, J. Hines, and J. Version Keith A. Arnold Dept.