Variable Seedeater
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| iVariable Seedeater | ||||||||||||||
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| Sporophila corvina (Sclater, 1860) |
The Variable Seedeater, Sporophila corvina, is a passerine bird which breeds from southern Mexico to northwestern Peru.
This seedeater is a common to abundant bird in lowlands and foothills up to 1500 m altitude in semi-open areas such as forest edges, roadsides, low scrub and gardens. It also flocks with other emberizid finches in pasture, weedy fields and other grassland.
The flimsy cup nest, built by the female, is made of coarse plant material and lined with a few finer fibres. It is placed in a tree 0.4 to 6 m up, occasionally higher, in the fork of a twig. The clutch is two or three brown-speckled pale grey eggs, which are incubated by the female alone for 12-14 days to hatching.
The Variable Seedeater is a robust bird with a black conical bill. It is 10.5 cm long and weighs 11 g. The adult male of the nominate Caribbean subspecies is entirely black apart from a white patch on each wing, white wing linings, and a white midline to the belly. The male of the Pacific subspecies aurita additionally has white neck patches, a white rump and white belly with black barring on the flanks. The very different appearance of the males of the two forms is, of course, the reason for this species’ name.
The adult female of nominate corvina is olive-brown above, paler below, and has white wing linings like the male. The female of Pacific aurita is generally paler and less brown than the Caribbean birds, and lacks the yellowish tint to the belly shown by the that subspecies. Young birds are like the adult female of their subspecies. Young males may not acquire full adult plumage in their first year, and may breed whilst still showing some immature features in their appearance.
The Variable Seedeater has a harsh chur call. The male’s song consists of a mixture of warbles, whistles, and twitters, and is more elaborate on the Pacific slope.
This species feeds mainly on grass seeds, but also takes other seeds, berries and some insects.
[edit] Taxonomic note
This species’ taxonomy is as variable as its name. It has sometimes been considered to be conspecific with the Wing-barred Seedeater, Sporophila americana of South America, and the Pacific subspecies is sometimes split from the all-black Caribbean form as Black Seedeater, S. aurita, but the two forms intergrade in central Panama.
[edit] References
- Hilty, Birds of Venezuela, ISBN 0-7136-6418-5
- Stiles and Skutch, A guide to the birds of Costa Rica, ISBN 0-0814-9600-4
