j.tweedie's picture


Observed: 30th May 2003 By: j.tweedie
S159 Neighbourhood Nature - course complete
j.tweedie’s reputation in Birdsj.tweedie’s reputation in Birdsj.tweedie’s reputation in Birds
Species interactions

No interactions present.


RoyW's picture

Juvenile or 1st Summer.

Most birdwatchers would probably describe this as a 1st summer rather than a juvenile. In late May it would be getting on for a year old, and now lacks the black 'half collar' on the neck of a juvenile + has a pale based bill. The wing feathers aren't moulted until a year old though, so these are retained juvenile feathers (and can be seen to be getting quite worn!).

j.tweedie's picture

I suppose, seeing these in

I suppose, seeing these in early summer, I should have realised it wasn't a juvenile anymore. When does a bird (in particular gulls) move from being classed as a juvenile to a 1st summer?

RoyW's picture

Most often when they moult!

Ageing of birds in the field is usually based on plumage so the age classification changes when the bird moults (and thus changes its appearance).
In gulls 'juveniles' usually become '1st winters' sometime in the autumn after they moult head and body feathers. Following a subsequent moult in late winter/early spring(again of head and body feathers) they will be '1st summers'. Some feathers are kept (eg. the juvenile wing feathers are retained until the second autumn), but because their has been a visible change in the plumage the birds 'age class' is changed.

Technically all birds are in their 1st winter at the end of the year that they are hatched, but some (eg. divers) are often still referred to as juveniles at this stage because they still have their juvenile plumage.