Swale Wader Group

 

Ring size D, although some females require an E.

SEXING

Except for Juveniles caught before 1st October all birds can be sexed on bill length, <88=male, >88=female. See chart below. Birds in breeding plumage can be easily sexed. Birds in winter plumage cannot be sexed on plumage.

RACE

Most birds are from the north-western Europe population Limosa lapponica lapponica, adults not moulting in August and September are of the race L.l. taymyrensis from western Siberia.

JUVENILES

Juveniles begin to arrive in late August and build up to about 70% of the population in October before dropping to around 25% of the population in December.

AGEING CALENDAR

July Birds in summer plumage that can be sexed on plumage. Birds not in summer plumage are first summer (EURING age code 5).
MALE: Red on underparts.
FEMALE: Various shades of buff and pink on breast only.
August Most adults will be in wing moult.
ADULT MALE: Most still retain red on belly and neck.
ADULT FEMALE: Some birds still retain some pink on breast.
JUVENILE: Very obviously different, buff tipped coverts and barred tertials.
September Most ADULTS will be in wing moult and a few will retain some breeding plumage.
JUVENILE: Feathers fresh, with buff edges to coverts and barred tertials.
October ADULTS: Fresh plumage, tertials uniform grey. Centre tail feathers without brown bars. Most will be in moult so not all birds can be measured.
JUVENILE: Barred tertials and coverts with buff edges.
November ADULTS: Many will be completing wing moult, check for growing longest primaries. Fresh plumage, tertials uniform grey. Centre tail feathers without brown bars.
JUVENILE: Barred tertials, and coverts with buff edges.
December ADULTS: Fresh plumage. Tertials uniform grey.
JUVENILE: Tertials, and Coverts with buff edges. Some birds have moulted central tail feathers and some tertials giving contrasting old worn barred and new plain grey feathers, tertials beginning to show wear.

Bar-tailed Godwit Ageing Images

Adult Bar-tailed Godwit

Juvenile Bar-tailed Godwit