Crane Hawk
Geranospiza caerulescens
Variably colored hawk with a small head and long legs. Frequents tropical lowlands, especially marshes, but also forest, woodland patches. Usually seen perched, at times clambering and flapping while using its double-jointed legs to grope around for prey in tree crevices. Adult has long reddish legs; Central American and northern South American birds have red eyes, while southern South American birds have yellow eyes. Immature has white-grizzled face. Long tail has 2 broad white bands, obvious in flight. Wingbeats rather loose and floppy, and soars rather infrequently.
分类信息
The crane hawk used to be many species that were recently[when?] lumped into one. Those species are now designated as subspecies. Color varies clinally, though, and it is now commonly accepted that they comprise one species. There are also two species of harrier-hawks in Africa of the genus Polyboroides that, while they are morphologically and behaviorally similar, are not very closely related. They serve as a good example of convergent evolution.<p>Six subspecies are recognised:
- 学名
- Geranospiza caerulescens
- 命名信息
- (Vieillot, 1817)
- 目
- Accipitriformes
- 科
- Accipitridae
- 属
- Geranospiza
分布与栖息地
Crane hawks occur in tropical lowlands at the edge of forests and are almost always closely associated with water. It is found in Argentina, Belize, Bolivia, Brazil, Colombia, Costa Rica, Ecuador, El Salvador, French Guiana, Guatemala, Guyana, Honduras, Mexico, Nicaragua, Panama, Paraguay, Peru, Suriname, Trinidad, Uruguay, and Venezuela. They are an irruptive and local migrant, probably moving in response to changing water conditions.
- 迁徙
- Resident species
行为
These hawks often forage by scanning from a perch or on the wing and swooping down to grab prey. However, they are notable for having “double-jointed” tarsal bones, allowing them to reach into tree cavities and extract prey, a trait they share with the genus of African harrier-hawks Polyboroides. Their main prey are small vertebrates, especially rodents, bats, lizards, snakes, frogs and small birds (especially nestlings of parrots and woodpeckers), but they have also been known to eat larger insects (such as beetles, cicadas and cockroaches), spiders, other arthropods and snails.[page needed]<p>During breeding, nests are built in tree canopies, often in clumps of orchids or other epiphytes. The nest is a shallow cup of twigs, anywhere from 10–25 metres up in a tree. Clutches are usually 1-2 white-or-bluish-tinged eggs.
保护状况
Nowhere is the crane hawk particularly common, but it is still widely distributed. However, it is considered threatened in Mexico, endangered in El Salvador, and at low risk in Argentina.
- 种群趋势
- declining
照片
分布
鸟叫声
其他鸟类
Olive Honeyeater
Lichmera argentauris
A nondescript sparrow-sized songbird with a slender, downcurved bill. Entirely olive-green above and uniform pale gray below, but note head pattern, which includes a prominent whitish smudge on the cheeks and dull bare skin below the eye. Juvenile has a pink facial patch. Singles, pairs, or groups inhabit scrubland, wooded areas, and coconut plantations in lowlands. Confined to islets in the Moluccas and to West Papua, where it is readily identified by its head pattern. Harsh, squeaky vocalizations include “tchew” and “grrt” notes and “chi-witchoo” or “witch-oo” phrases.
Black-bellied Thorntail
Discosura langsdorffi
Tiny, coquette-like hummingbird. Males are iridescent emerald green with a black belly, bold white rump band, short crest, and long, straight tail feathers. Females are similar, but are duller below with a shorter tail. Compared to the similar Festive Coquette, females have darker plumage. Usually found in mature rainforest, where it forages at flowering trees at all levels of the forest.
Dusky-headed Brushfinch
Atlapetes fuscoolivaceus
This Colombian endemic has a limited range in the southern Andes, where it can be found in both the eastern and central cordilleras. It has dark upperparts, yellow underparts, and a distinctive black mustache stripe. Young birds are paler on the head and may show indistinct streaking below. The lack of any crown stripe or crown patch helps separate it from juveniles of other brushfinches, which otherwise can look similar. Inhabits tangles in clearings and at edge of cloud forest, but generally avoids forest interior. Vocalizations include a short series of chips and clear whistles and a fast, descending chatter.
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