Swainson'S Hawk

buteo swainsoni

Swainson's Hawk is an elegant, medium-sized raptor of the Americas, renowned for its extraordinary long-distance migrations and its surprising dietary preferences. Often called the 'grasshopper hawk,' this bird of prey breeds in the open grasslands and agricultural fields of western North America during the summer, before embarking on an epic 10,000-kilometer journey to spend the winter in the pampas of Argentina. They are highly social raptors, frequently gathering in massive flocks numbering in the thousands during their migration corridor. While they hunt small mammals to feed their chicks during the nesting season, adult Swainson's Hawks outside of the breeding season feed almost exclusively on large insects like grasshoppers and dragonflies. This behavior makes them highly beneficial to farmers, as they provide natural pest control. Watching a flock of these graceful hawks follow a tractor in a freshly plowed field is a spectacular sight for nature lovers.

生息地: Typically found in wide-open country, including native grasslands, prairies, pastures, and agricultural fields of western North America.

外見

Swainson's Hawk is characterized by its long, narrow, pointed wings and a relatively short tail. It features a highly distinctive 'bib'—a dark brown band across the breast that contrasts sharply with its white throat and pale belly. Most individuals are light-morph, showing a dark brown back, a rufous-to-brown chest bib, and underwings that have light coverts contrasting with dark flight feathers. When soaring, they hold their wings in a slight dihedral V-shape, similar to a turkey vulture.

界Animalia門Chordata綱Aves目Accipitriformes科Accipitridae属Buteo

Swainson'S Hawk

カテゴリ

鳥類

レア度

Common

危険度

1/5 · 非常に低い

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おもしろい事実

A single flock of migrating Swainson's Hawks, known as a 'kettle', can contain tens of thousands of individual birds filling the sky.

Because they consume massive quantities of agricultural pests, they are highly welcomed by farmers and are often referred to as 'locust hawks'.

During their winter stay in Argentina, they live almost entirely in agricultural fields, feeding alongside agricultural machinery to catch flushed insects.

特殊能力

Undertakes one of the longest migrations of any North American raptor, traveling over 10,000 kilometers each way between northern breeding grounds and South American wintering pampas.

Saves energy during long flights by riding columns of rising warm air, allowing it to glide for hours with minimal flapping.

Possesses remarkable agility on the ground, allowing it to easily walk, run, and hop to capture grasshoppers and other large insects.

サイズと詳細

長さ: 43+ cm
翼開長: 117+ cm
体重: 0.5+ kg
寿命: 10+ 年
Top Speed: 60 km/h
一度の産卵数: 1+
抱卵期間: 28+ 日
渡りの距離: 12000 km

食性と食事

Feeds heavily on small mammals like voles and pocket gophers during the nesting season, but transitions to an almost exclusively insectivorous diet of grasshoppers and crickets during the rest of the year.

年齢による違い: Chicks are fed a high-protein diet consisting primarily of rodents and reptiles, whereas adults during non-breeding periods rely almost entirely on large insects.