Articles - Black-tailed and Bar-tailed Godwits
Black-tailed Godwit by Steve Young
Keith Vinicombe - Posted on 01 Jan 2010
Key featured species
- Black-tailed Godwit Limosa limosa
- Bar-tailed Godwit Limosa lapponica
Although these two godwits are readily distinguishable in flight, in winter they are superficially similar when on the ground.
Bar-tailed Godwit is a more northerly breeding species than Black-tailed, its summer range extending from northern Scandinavia eastwards across the tundra of northern Russia. Western breeders commonly winter in
Breeders in central
The Black-tailed Godwits that winter in
Separating the two species in flight is easy. Black-tailed has a striking white wing stripe, framed in black, and a square white rump that contrasts with its black tail. Its underwing too is white, and again is framed by black leading and trailing edges. In addition, Black-tailed is a sleek, elongated bird in flight, its long legs protruding well beyond the tail and counterbalancing its long neck and bill.
Bar-tailed is stockier-looking when flying, with shorter legs that barely extend beyond its tail. In plumage, Bar-tailed resembles a Curlew or a Whimbrel, being essentially brown with a barred tail; most significantly, it lacks a wing-bar and shows a white ‘V’ up its back. The underwing is plain whitish.
Bar-tailed Godwit is in fact more likely to be confused with the similarly sized Whimbrel, particularly in spring when small numbers of the latter often tag onto migrating flocks of ‘Bar-wits’ as they head up the English Channel. When its decurved bill isn’t apparent, Whimbrel can often be picked out by its ‘head-up, crop-heavy’ appearance, whereby the upper breast seems to bulge more, and in a direct comparison Bar-tailed is seen to be slightly smaller and slimmer-winged. Whimbrel has darker, more uniform plumage tones than Bar-tailed, which is paler above with darker, contrasting primaries and whiter underwings.
Another pointer is that whereas Bar-taileds often form large and purposeful flocks, Whimbrel tend to form small groups or straggly lines. When heard, Whimbrel’s descending seven-noted whistle is an instant give-away.
On the ground
Distinguishing between the two godwits on the ground is a different matter, and here shape and structure come into play again. Bar-tailed is a shorter-necked, shorter-legged and stockier-looking bird than Black-tailed, with an upward curvature to the bill that is visible in closer views. Black-tailed is much more elegant, being longer-billed and longer-legged.
To separate them in winter plumage, look first at their upperpart patterning: Black-tailed is uniformly plain smoky grey, whereas Bar-tailed has strongly variegated upperparts with prominent pale feather fringes. (It is always useful to think of Bar-tailed as having upperparts like a Curlew.) Bar-tailed also shows a longer, more prominent supercilium.
Black-tailed Godwit has a variety of calls but in flight it usually gives a rather soft kik or kik-ik, which may sound conversational in a flock. It is sometimes elongated into a more musical kik-ik-ik-ik. Bar-tailed’s call is a rather distinctive, mellow and rhythmic ik-ik, which is loud and emphatic compared with that of Black-tailed, although it too may be elongated into an ik-ik-ik-ik.
Although this article is concerned mainly with the identification of Black-tailed and Bar-tailed Godwits in winter, the following points are also worth remembering.
In both species the juveniles show neat, immaculate plumage in late summer and early autumn, unlike the adults which are usually in a rather messy state, showing a patchy mixture of moth-eaten deep orange summer plumage and fresh grey winter feathering. Juvenile Black-taileds are finely scalloped above, whereas juvenile Bar-taileds, like adults, show variegated upperparts similar to those of Curlew. Juvenile Bar-taileds are warm buff below, in contrast to juvenile Icelandic Black-taileds, which are quite a bright, rather deep orange. In fact, the brightness of their plumage often confuses people into thinking they are summer-plumaged adults.
In spring, our wintering Bar-tailed Godwits depart in February and March to moulting grounds on the
Male ‘Bar-wits’ in summer are stunningly attractive, being uniformly and evenly dark chestnut-red below. Summer females, however, remain ‘winter-like’: most are largely white below, although many acquire a scattering of rufous-cinnamon feathering and others show a paler pinky buff or cream coloration, as well as some delicate grey streaking and barring. Adults can thus be readily sexed in spring, but note that the first-summer birds of either sex that remain in their winter quarters acquire very little summer plumage (Cramp and Simmons 1983).
In both species, the bill of the female is longer than that of the male. Female Bar-tailed’s bill is about 20 per cent longer, and female Black-tailed’s is 12-15 per cent longer.