AGE – BEST CRITERIA:
Ageing Wrens is often a challenge and both care and some experience is required. Because of the restricted pre-breeding moult, autumn criterias are still applicable. In 2cy, a moult contrast is (nearly always) present in GC, most often in the central part of the arm. More rarely, all or no GC were included. When no GC were moulted it’s sometimes possible to se moult contrast between the juvenile GC and the post-juvenile MC. In cases where all GC were moulted it’s possible – but still difficult – to detect moult contrast between the post-juvenile GC and juvenile PC and SS. Moult contrasts may also be found in the alula, the TT or the tail. Adult birds show a uniform plumage. Difficult birds are not uncommon and should, of course, be left without age.
2cy:
- Most birds included 4-7 inner GC in the post-juvenile moult and, hence, the contrast is often found in the central part of the arm. There is a pronounced individual variation regarding the pattern and colour of the feathers, but any 1cy bird can be expected to show two types of pattern; a juvenile type and an adult type respectively. Juvenile GC generally show a warm brown basic colour, warm buff tips, less distinct dark markings overall. Post-juvenile GC often show a colder brown (with a slight olive tone) basic colour, more distinct dark markings and often (but far from always) a tendency to show a pale/whitish tip.
- Juvenile PC are warm brown with sparse blackish barring, but variation is quite extensive. Some may lack obvious bars while some show more prominent barring, although in general still less well marked than in adult.
- Juvenile PP and SS show dark barring that usually are slightly more ill-defined and more narrow than in adult feathers. The pale spots (and the connecting dark markings) on outer vane of PP (esp. in P3-4) are slightly less distinct and on average fewer in number than on adult. According to Ward & Feu (2006) juvenile P4 show 7-9 pale spots compared to 9-12 in adult.
- Juvenile RR shows dark markings that usually are less distinct and narrower than in adult, but uniform tails (with no moult contrast present) are frequently hard to judge. Note also that some birds may have replaced all juvenile RR in post-juvenile moult, resulting in a tail that is irrelevant for ageing.
- Juvenile TT are on average slightly warmer brown with ill-defined narrow bars or only scattered dark markings. Many birds show contrast to moulted TT of adult type with slightly more distinct barring.
3cy+:
- Adults show a uniform plumage with no moult contrast and in better general condition.
- GC have a colder brown and/or slight olive tone and, on average, stronger dark markings. Adult type feathers often, but not always, show whitish tips.
- PC generally show more prominently black barring.
- PP and SS show, on average, more distinct black markings forming bars across the wing. The outer vane of PP (esp. on P3-4) show, on average, more well defined white and black markings than in juvenile. According to Ward & Feu (2006) adult P4 show 9-12 pale spots compared to 7-9 in juvenile.
- TT show more distinct black markings, in most cases forming bars.