Purple martins are the biggest swallows in North America, and they are about 20.3 cm long. They weigh around 56 g and their wingspan is approximately 45.7 cm. Males are a little bit bigger, and their feathers are shiny and such a dark purple that they are almost black. Their heads and backs are shinier than their wings. Females are gray or gray-blue with darker wings and darker feathers on top of their heads. They have white breasts smudged with different shades of gray. Eastern females are darker overall than eastern ones. Their dark black-brown bills are 8.2 mm long in males and 8.5 mm long in females. The inside of their mouth is yellow in young birds and orangey-brown in adults. Their legs and feet are black-brown and their eyes are dark brown. (Brown, 1997; Layton, 1972; Wade, 1966)
Young purple martins are gray to black and have white bellies and gray streaks on their breasts. Young look different from adult females because their bellies are much more obviously white rather than gray. When young purple martins fly, their tail may have a small fork, but adult tails are wider and definitely forked. (Brown, 1997; Layton, 1972; Wade, 1966)
Purple martins can be found across North and South America, depending on the season. They live and breed in North and Central America and spend the winter in South America. In the summer, they can be found as far north as Alberta, Saskatchewan, and Manitoba in Canada. They breed across the eastern half of the United States, and also might be found along the coast of the Pacific Ocean or along California's Baja Peninsula. In the winter, they can be found in Colombia, Venezuela, Guyana, Suriname, Ecuador, Peru, Brazil, Bolivia, Paraguay and Argentina. They live east of the Andes mountains, especially in Bolivia and parts of Brazil. (Brauning, 1992; Brown, 1997; Johnston, 1966)
Purple martins prefer to live in open spaces close to water, because they find lots of insects to eat near wetlands, swamps, and wet meadows. Purple martins are very used to humans and live in man-made birdhouses designed specially for them. Before martin houses, they lived at the edges of forests, in mountain forests, and deserts. Some purple martins in the western United States still live in these natural habitats, but most nest in man-made martin houses. Purple martins are usually found at elevations between 100 m and 4,000 m. (Brauning, 1992; Brown, 1997)
When they are traveling between summer and winter locations, they rest in different kinds of habitats. These could be cities, open areas, or high mountains in Venezuela and Columbia. They fly along the coast and cross the Gulf of Mexico. In the winter in South America, they stay in rainforests, farm fields, clearings, and sometimes cities. (Brauning, 1992; Brown, 1997)
One male and one female purple martin form a pair each year to breed and raise their young. Males arrive first to the breeding location and find two possible nest locations to show off to females. Males are very territorial and will aggressively defend the nest sites from other males. Males fly out from their nests in a wide arc, swoop back inside the nest, and then pop their head out singing. This is supposed to attract females, who actually pay more attention to whether the nest is good or not. After pairs form, males defend their nest site and their partner. (Brown, 1979; Brown, 1997; Johnston and Hardy, 1962)
Once purple martins are in pairs, they start building a nest. They build the nest about one month before they female lays eggs. They use green leaves, grass, sticks, paper, mud, and feathers. Scientists aren't sure why they use green leaves in the nest. Females do most of the building while males gather nest materials and defend the spot from other purple martins. They used to build all their nests in holes in trees, but now they mostly nest in man-made "martin houses." (Brown, 1978; Brown, 1997)
Purple martins breed between May and June. Females lay 3 to 8 white oval-shaped eggs, but usually lay 5. The eggs are about 2.4 cm long and 1.7 cm wide. They take 15 to 18 days to hatch. The chicks can fly after 26 to 31 days and travel in a family group. The group comes back to the nest to sleep for several days. After 7 to 10 days, the chicks are able to survive on their own and leave the family group. Purple martins can reproduce when they are 1 year old. (Brown, 1978; Brown, 1997)
Females keep the eggs warm for 15 to 18 days until they hatch. If females leave the nest, males take over keeping the eggs warm. However, this doesn't happen often. When chicks are born, they have no feathers, and can't open their eyes or feed themselves. After the chicks hatch, females keep them warm in the nest for 10 more days. Parents feed the young until they can fly, and for 5 to 7 days after. Both males and females feed the chicks undigested food they throw up into the mouths of the chicks. If the piece of food is too big for the chick to swallow right away, the parents take it out of their mouth right away. After two weeks, females stop sleeping with the chicks because it is no longer necessary. (Alsop III, 2002; Brown, 1980; Brown, 1997; Layton, 1972)
Purple martins can live up to 13 years and nine months. If there is severe weather for 3 to 4 days, the number of insects decreases quickly and they sometimes starve. They can also die from the parasites in their bodies. (Brown, 1997; Layton, 1972)
Purple martins are are active during the day and are most active at dawn and dusk. They live together in colonies, which are very large groups of birds. Although mating pairs are very protective of their territory, they become loyal to the whole group when they join a colony. During the day, they fly around in pairs or stay in their colonial groups. In a colony, the whole group works together to improve their reproductive success, but disease and competition are more common. Colonies are social and 3 or more purple martins from the colony go out and explore their surroundings together. This involves visiting other colonies, scoping out potential food sources, and visiting nearby streams and swamps. Purple martins search for food together in large flocks. When the groups find food, they call over the rest of the colony to come feed. The whole colony flies back to South America at the end of the summer. Tens of thousands of purple martins might fly back together at the same time. (Alsop III, 2002; Johnston and Hardy, 1962)
Purple martins can get aggressive if they are threatened. For example, they defend themselves by pecking and flapping their wings, trying to get the intruder to leave. They also sing to alert other purple martins, or open their mouth wide at the possible threat. They might also lunge or snap their bills to intimidate. (Alsop III, 2002; Johnston and Hardy, 1962)
Purple martins often return to the same nesting site as the year before. Scientists don't know how far they go looking for food, but it is likely a long ways because they can fly very far. They travel 2.8 to 664 km to get back to their nests. (Brown, 1997)
Purple martins communicate by singing and body language. They make 11 different noises that are used for mating, warning, and teaching the young to fly. Males attract females by singing and showing off. Young purple martins make noises that sound like "choo-choo" to get their parents' attention if they need protection. Parents make the same noise to bring their chicks together and bring them safely back to the nest. Females make the noise "choo" to lead their young when they are learning to fly. Purple martins make "zwarck" calls for serious alarm, and often dive straight down at the threat while making this noise. Males make the sound "hee-hee" to fight off intruders. "Zweet" are warnings of possible threats or other excitement between purple martins. "Cher" noises are for day-to-day communication and "chortle" noises are for excitement situations. Males attract females by singing ‘croak songs,’ which also warn other males to stay away from their territory. They also make a clicking sound with their beak during courtship. They make ‘subsongs’ while feeding and before migrating. Males in stable colonies perform a 'dawnsong' win the early morning, which is a lot of different sounds. Like all birds, purple martins use their senses of sight, sound, smell, taste, and touch. (Brown, 1978; Brown, 1984; Brown, 1997; Johnston and Hardy, 1962; Morton, 1985)
Purple martins primarily eat insects, which they capture in flight or grab from leaves or off the ground. They prefer to eat fruit flies, mosquitoes, wasps, beetles, ants, grasshoppers, cicadas and dragonflies. They can eat 400 flies or 2000 mosquitoes in just one day. (Brown, 1997; Campbell Finlay, 1976; Layton, 1972)
Purple martins rarely eat spiders and prefer any other kind of insect. They diet is about 23% wasps and bees, 16% flies, 15% assorted bugs like stink bugs and black bugs, and 12% were beetles. Purple martins also eat butterflies and moths and prefer dragonflies. Young purple martins prefer to eat dragonflies over other insects. (Brown, 1997; Campbell Finlay, 1976; Layton, 1972)
Weather affects the number of insects available, so it definitely affects purple martins. When it's cold outside or very windy, the number of insects decreases. When it's hot outside, there are plenty of insects to eat. In August, the most insects are available to eat, which helps them get ready for their long flight south. Purple martins consume water in flight by skimming over water. (Brown, 1997; Campbell Finlay, 1976; Layton, 1972)
The most common predators for purple martins are owls and snakes which prey on both adults and juveniles. Owls attack while the birds are inside the nest. Owls grab the nest and shake it, which disorientates the purple martin inside. The bird then tries to slip out of the entrance hole where the owl grabs it with its claw. Humans can help prevent these owl attacks by attaching curved rods over nest entrances so that owls cannot perch atop the martin houses. Owls have also been known to reach their claws into martin houses to grab any unfortunate purple martin. (Brown, 1997; Kostka, 2000; Layton, 1972)
Predators like snakes or raccoons are able to climb birdhouse poles and make their way to the entrance cavities. They pull out any adult birds and then proceed to eat the eggs. Rat snakes are the most common snake predators. Hawks and blue herons are the only two predators that prey on purple martins in the air. House cats prey on purple martins when they are on the ground in search of nesting material. Squirrels also prey on purple martins by climbing up the nest and entering the cavity. The squirrel then kills the young, breaks up all the eggs and can even take over the nest to raise its own young. (Brown, 1997; Kostka, 2000; Layton, 1972)
An interesting behavior that avoids predators is constant nest cleaning. Purple martin parents eat or remove any body waste from the nest that smells like the chicks. They also warn each other about predators by making the "zweet" call and dive bomb their attackers. When living in a colony, purple martins are able to quickly discover predators. If a predator approaches a colony, purple martins gather in a crowd to confuse them. They generally only attack if the predator comes within a few meters of their personal nest or young. (Brown, 1997; Kostka, 2000; Layton, 1972)
Purple martins are predators, prey, competitors, and hosts to parasites. They are insect-eaters that control numbers of pest insects. Mites that live outside their nests can decrease the number of chicks and even cause abandonment of a colony if an outbreak happens. Other parasites that live on them are ticks, beetles, louseflies, fleas, and bowflies. (Brown, 1997; Kostka, 2000; Layton, 1972; Moss and Camin, 1970; Wade, 1966)
Purple martins compete for nesting sites with house sparrows and European starlings. Starlings corner purple martins in their own nests and will fight, even to the death. House sparrows and European starlings are both invasive species in the United States and often out-compete native purple martins for nesting habitat. (Brown, 1997; Kostka, 2000; Layton, 1972; Moss and Camin, 1970; Wade, 1966)
There are no known adverse effects of purple martins on humans.
Purple martins consume large quantities of species that are pests to humans including flies, stink bugs, clover weevil beetles, and mosquitoes. They are beautiful birds that are enjoyed by many bird watchers. (Wade, 1966)
Purple martins are a species of "least concern" on the IUCN Red List, have steady numbers, and live in a wide area. However, they are a "species of concern" on the U.S. federal list, and several groups are working to conserve their natural habitat. Their numbers have declined some in Canada. They are considered at risk in British Columbia, so special nesting boxes are being set up for them. In the places they live that are farther north, local groups of purple martins have died from severe weather. Purple martins struggle because of nest competition with invasive house sparrows and European starlings. (Brown, 1997; Fraser, et al., 1997)
Nadine Snyman (author), University of Alberta, Augustana Campus, Doris Audet (editor), University of Alberta, Augustana Campus, Rachelle Sterling (editor), Special Projects, Catherine Kent (editor), Special Projects.
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
living in the southern part of the New World. In other words, Central and South America.
uses sound to communicate
living in landscapes dominated by human agriculture.
young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.
Referring to an animal that lives in trees; tree-climbing.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends.
a wetland area rich in accumulated plant material and with acidic soils surrounding a body of open water. Bogs have a flora dominated by sedges, heaths, and sphagnum.
an animal that mainly eats meat
uses smells or other chemicals to communicate
to jointly display, usually with sounds, at the same time as two or more other individuals of the same or different species
used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.
active at dawn and dusk
in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.
to jointly display, usually with sounds in a highly coordinated fashion, at the same time as one other individual of the same species, often a mate
animals that generate their own body heat through metabolic processes.
parental care is carried out by females
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
An animal that eats mainly insects or spiders.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
parental care is carried out by males
marshes are wetland areas often dominated by grasses and reeds.
makes seasonal movements between breeding and wintering grounds
Having one mate at a time.
having the capacity to move from one place to another.
This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.
the area in which the animal is naturally found, the region in which it is endemic.
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).
breeding is confined to a particular season
reproduction that includes combining the genetic contribution of two individuals, a male and a female
associates with others of its species; forms social groups.
living in residential areas on the outskirts of large cities or towns.
a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.
uses touch to communicate
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
Living on the ground.
defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.
living in cities and large towns, landscapes dominated by human structures and activity.
uses sight to communicate
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