RED-THROATED DIVER Gavia stellata

RED-THROATED DIVER Gavia stellata 

Red-throated Loon

L 53–69 cm, WS 106–116 cm.

IDENTIFICATION 

Smallest and most elegant of the divers, showing gently rounded head shape, relatively slim neck and fine, generally upturned, bill. (Note: when neck retracted appears stockier, recalling Black-throated.) Often holds head and bill pointing markedly upwards (typical of much larger Yellow-billed also, but unusual in other divers). Diving action smooth and quick with a slight jump (other divers do not normally show even a slight jump). Adult summer distinguished by lack of bold white markings on upperparts, dark reddish-brown patch on foreneck (which can look blackish in poor light), grey head and sides to neck, and fine black and white stripes on hindneck. Adult winter distinguished by extensive white on head/neck, with white typically extending above and in front of eye and well towards back of neck (so that eye stands out clearly and white sides to face/neck are visible even in rear view), and paler, greyer-looking upperparts. At close range the latter can be seen to be dark greybrown covered in numerous oval white spots. Birds moulting into adult summer plumage have this head/ neck pattern obscured (with dark foreneck patch and grey feathering coming through). Distinguished from summer Black-throated by lack of large white markings on upperparts. Juvenile has less obvious, dingybuff feather edgings above and a dusky brown throat, face and foreneck. Distinguished from Black-throated by lack of clean-cut white flank patch (but beware white showing on preening birds rolled over on side), pale feather edgings on most of upperparts (if visible), differences in shape of neck, head and bill, and (compared to adult) less distinct head/neck pattern. 

Amount of white on face and foreneck usually increases during first autumn and winter, with throat becoming all white (and eye often being ringed with white, unlike Black-throated). In flight, wings appear to be set further back along body and rear end seems shorter than in other divers, probably because wings are more backward-angled and because feet project less prominently. Shows less obvious dark flank line dividing pale underwing from pale belly and has distinctive habit of turning head from side to side (rarely seen in other divers). Wingbeats faster and upstroke higher than in other species. Often looks even more humpbacked owing to well-drooped head and neck.

SEX/AGE 

Juvenile resembles adult winter, but is duller: shows dusky face and sides of neck (these areas suffused with greyish-brown) and browner upperparts with less obvious, pale buff spots. Adopts partial adult summer plumage in late spring/early summer of second calendar year.

VOICE 

Flight call a rapid goose-like cackle: ‘gwukgwuk- gwuk-gwuk’, synchronized with wingbeats. On breeding grounds male has repeated loud, rolling, growling ‘oorroo-ugh, oorroo-ugh’ call. Female makes similar but longer, more moaning ‘aarroo, aarroo’ call. Also a barking call and a descending wailing call resembling a cat’s meow: ‘eeaaooh’.

STATUS/HABITAT 

Locally fairly common. (In addition to mapped range, has bred Estonia.) Breeds by shallow pools and lakes; sometimes by marine inlets. At other times found in coastal waters, especially shallow sandy bays; rarely on inland lakes.