AGE – BEST CRITERIA:
Most individuals are possible to age on the shape of the RR alone, but more difficult tails are regularly seen. Moult contrast is present in the wing of 1cy, generally between post-juvenile MC and juvenile GC, but a few birds have also included some inner GC. However, these moult contrasts are generally difficult to detect, and great care should be taken since many birds also show ‘false contrasts’ created by a sudden change of the pattern on the inner GC. In difficult birds, skull ossification is often helpful. Adult birds show a uniform and freshly moulted plumage with broader and more blunt tipped RR.
- In most birds, narrower and slightly more pointed RR than 2cy+, often with a typical juvenile quality (less dense, slightly more brownish and generally more worn). Note, however, that some are intermidiates in this respect and should be examined more thoroughly.
- Juvenile PC are generally less dense, more brownish worn and slightly narrower than in adult, but differences are often very slight.
- Those few individuals that have included inner GC in the moult show a contrast with the new feathers being slightly more fresh, more green in the tips and a very slightly darker centre.
- In difficult birds, skull ossification should be checked. 1cy may show fully ossified skull as early as mid september.
- Colour of Iris is generally colder grey.
- Tips of RR generally blunter and broader, and the feathers are often of a generally better quality.
- PC are generally more dense and darker grey with better gloss, but differences are often very slight.
- Uniform wing lacking any moult contrast.
- Color of iris is generally slightly warmer brownish-grey.