Round-tailed cattle

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Round-tailed cattle
Round-tailed sparrow sounds? / I

Audio file / audio sample Sounds of the round-tailed sparrow ? / i

Systematics
Class : Birds (aves)
Order : Birds of prey (Accipitriformes)
Family : Hawk species (Accipitridae)
Genre : Hawks and sparrowhawks ( Accipiter )
Type : Round-tailed cattle
Scientific name
Accipiter cooperii
( Bonaparte , 1828)

The round-tailed sparrow ( Accipiter cooperii ) is a medium-sized hawk -like species that is native to North America. Its distribution area extends from Canada via the United States to Mexico . As usual with birds of prey, the male is smaller than the female in round-tailed sparrows. Birds living east of the Mississippi are on average larger than their western counterparts.

Taxonomy

The round-tailed cattle was scientifically described in 1828 by the French naturalist Charles Lucien Bonaparte . The species name goes back to the naturalist William Cooper , a co-founder of the American Museum of Natural History in New York City .

description

Comparison of a round-tailed sparrow (left) with a corner- tailed sparrow (right)

The average size of an adult male is 39 centimeters (variation width 37-41 centimeters), it weighs 312 grams (variation width 302-402 grams) and has a wingspan of 71 centimeters (variation width 70-77 centimeters). Adult males are much smaller than females (reverse sex dimorphism ), who are on average 45 centimeters tall (variation width 42 - 47 centimeters), weigh 500 grams (variation width 479 - 678 grams) and reach a wingspan of 83 centimeters (variation width 79 - 87 centimeters ).

Birds living east of the Mississippi are larger and heavier than their western counterparts. So has z. For example, a male from the eastern population has an average wing width of 236.1 millimeters and weighs an average of 327.7 grams. Males of the western population, on the other hand, have an average wing width of only 224.9 millimeters and weigh an average of 281.7 grams.

The young birds of round-tailed sparrows are slightly larger than corner- tailed sparrows , but smaller than the American goshawk . Smaller males are roughly comparable to large females of the corner-tailed sparrow and large females of the round-tailed sparrow reach the proportions of smaller male hawks .

Round-tailed sparrows have short, rounded wings and a very long, rounded tail that is alternately light and dark stripes. Adults have red eyes and a dark cap, the feather feathers are blue-gray; The sides of the head, chest and abdominal plumage are white with thin brown-red stripes. A white streak of eyes may appear over the eyes. Young birds have yellow eyes, their cap is brown, the cover feathers are also brown; The sides of the head, chest and abdominal plumage are light with thin black stripes. The tail is blue-gray with black stripes on the upper side, the underside is light colored.

The beak and claws of round-tailed sparrows are dark to black, legs and toes are yellowish.

Distribution and habitat

The breeding areas of the round-tailed sparrow extend from southern Canada to northern Mexico. Compared to the corner-tailed corsair and the American goshawk, their breeding spaces are generally located further south. In winter , the Canadian and northern US populations migrate south, and some round-tailed corsair even reach Panama on their migration . As nesting places, round-tailed corsair prefer forests adjacent to open fields, the edges of which offer them hunting opportunities. They are territorial and require a territory of a few square kilometers. Round-tailed sparrows prefer deciduous forests and generally avoid open spaces.

Round-tailed sparrows are attracted to feeding devices by smaller birds

Flight and hunting behavior

Round-tailed caterpillars are extremely agile fliers, their long tail also enables them to make abrupt changes of direction. The hunt is usually carried out from a stand guard. After recognizing its prey, the round-tailed cattle flies up powerfully, thrusts down at lightning speed, grabs with its fangs and usually kills its victim with one bite.

Prey animals

Round-tailed sparrows beat their prey out of protective bushes or in rapid flight through dense vegetation, completely relying on the surprise effect. Their prey are mostly medium-sized birds, including typically robins , woodpeckers , starlings , blackbirds and pigeons . The size of the struck prey ranges from wood warblers to pheasants . Round-tailed sparrows also prey on small mammals , especially rodents such as B. chipmunks and tree squirrels . The size range of captured mammals varies from small mice to rabbits . But lizards , frogs , snakes and larger insects are also captured. Round-tailed corsairs often pluck their prey on posts or other resting places. Recently, they have been hunting more and more songbirds near feeders . They then lurk in the surrounding trees with a view of the feeding station, suddenly stumble down and scare away the flock of birds to grab one of the victims on the flight.

Reproduction and breeding

Young bird

Round-tailed sparrows usually become sexually mature at two years of age, females sometimes as early as one year. The mating season is accompanied by courtship flights and lasts from March to June, depending on the distribution area. Couples found remain true to each other throughout their lives.

Round-tailed sparrows usually breed in forest areas. The breeding pair builds a nest from twigs and brushwood in the forks of high trees near the trunk. The clutch usually consists of three to five eggs. The cobalt blue eggs are around 48 × 38 millimeters in size and weigh around 43 grams. The breeding season lasts an average of 30 to 36 days. When hatched, the young weigh around 28 grams, are 9 centimeters tall and are completely covered by a white downy fluff. The female incubates them for two weeks, during which time the male searches for food. The young fledglings after 25 to 34 days, but they usually come back to the nest to be fed for another four weeks.

Enemies

It happens that eggs or nesting birds are occasionally preyed on by raccoons , crows and other competing round-tailed sparrows . Adult animals are sometimes struck by red-tailed buzzards , great horned owls and hawks.

Life expectancy

Round-tailed sparrows can reach an age of ten years under favorable circumstances.

Status and species protection

Young round-tailed cattle

Round-tailed corsair were once heavily hunted because they were suspected of preying on poultry - for this reason they were often referred to as “goshawks”. It has been found, however, that round-tailed boar seldom prey on domestic animals and consequently are now rarely hunted. By using pesticides such as B. DDT , the reproduction of round-tailed sparrows was severely impaired, but this threat has ceased with the ban on DDT and the adaptable bird of prey can now gradually replenish its populations. They are currently listed as "not at risk" in the IUCN Red List . Nevertheless, round-tailed sparrows are still subject to a strong threat in their traditional areas of distribution due to habitat destruction (deforestation, etc.).

Individual evidence

  1. ^ A b Wheeler, BK and Clark, WS 1995. A Photographic Guide to North American Raptors. Academic Press. San Diego
  2. ^ Bent, AC 1937. Life Histories of North American birds of prey. US National Museum Bulletin. 167: 147-165. Wash. DC

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Web links

Commons : Accipiter cooperii  - album with pictures, videos and audio files