Troglodytes troglodytes - Autumn

AGE – BEST CRITERIA:

Ageing Wrens is often a challenge and both care and some experience is required. In 1cy, a moult contrast is (nearly always) present in GC, most often in the central part of the arm. More rarely, all or no GC are included. When no GC are moulted it’s sometimes possible to se moult contrast between the juvenile GC and the post-juvenile MC. In cases where all GC are 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 and freshly moulted plumage. Difficult birds are not uncommon and should, of course, be left without age.

1cy:

Most birds include 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 replace 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.

2cy+:

Adults show fresh plumage with no moult contrast.
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.

1cy October. Juvenile GC1-5 are warm brown with buff tips and rather diffuse dark markings that contrast to post-juvenile GC6-10 that are slightly colder brown, show tendency to whitish tips and more distinct dark markings. Although the individual variation is vast, the shape of the dark markings in the two GC generations within the same bird often differ from eachother. [CP41574]

1cy October, showing variation with GC1-4 juvenile, showing a (slight, but still) contrast to inner post-juvenile GC5-10 in the same way as described to the left. [CP41596]

1cy October. GC1-4 are juvenile, contrasting to inner GC5-10. Note the sudden change in the brown basic colour as well as in colour and shape of the dark markings. [CP41632]

1cy October. An unusually rufous and sparsley patterned individual included to show variation. GC1-6 are juvenile but the contrast to the post-juvenile (and slightly more olive toned) GC7 is less easy to see since this feather is partly hidden under the scapulars. [CS00084]

2cy+ October. All GC are of uniformly adult (post-breeding) type. Fresh, cold brown with distinctive dark markings. Many adult show tendency to have white tips to the GC but, as seen here, all do not. Note that the top barbs on GC4 has accidentally been lost. [CP42386]

2cy+ October, showing variation. Note fresh and uniform GC, cold brown basic colour and distinct dark markings. [CP42043]

1cy October. SS and PP show a typically juvenile pattern with rather diffuse and slightly irregular dark bars in the outer vanes. The barring on the outer PP is in dark grey with the pale spots being dark buff in colour, less contrasting than in average adult birds. According to Ward & Feu (2006) juvenile P4 in British Wrens show 7-9 pale spots compared to 9-12 in adult P4. However, some birds (like this one) show spots that are less easy to count. Note that GC1-10 are all post-juvenile. [CP41538]

1cy October, showing variation. Note that the number of pale spots on the outer vane of PP3-4 is lower (on average) than in adult birds. Note also the juvenile GC1-4. [CP41596]

2cy+ October. Adult birds show a uniformly fresh wing with prominent barring formed by well defined black bars. On PP3-4 the pale spots are paler (sometimes whitish), more contrasting to the blackish feather, and also more numerous than in juvenile PP (see above). Note also typical adult type GC with whitish tips and distinct black subterminal bar. [CS00450]

2cy+ November, showing variation with slightly more buffish pale spotting on the outer PP. [CP42386]

1cy October. Juvenile PC are, on average, warmer brown with slightly more diffuse dark markings. Note also that the longest AL is moulted (contrasting to central juvenile AL) and the visible moult contrast in the GC, with juvenile outer GC1-3. [CS00083]

1cy October. A rufous and sparsley patterned individual, showing variation. Note moult contrast in AL (longest one is moulted post-juvenile). [CS00084]

2cy+ October. Adult PC are colder brown and show more distinct black markings. Note the uniformity in the pattern from GC, PC and AL, with white tip, black subterminal band and contrasting black/brown overall. [CS00450]

2cy+ November, showing variation. [CP42386]

1cy October. Juvenile RR show dark barring that generally is slightly more narrow and less distinct. However, due to extensive variation it's very difficult to tell the generations apart unless they are present in the same individual (and unfortunately we have yet no autumn bird with moult contrast in the tail, to show here). [CP41691]

2cy+ October. Tail pattern in both juvenile and adult are very variable but, in general, adult feathers show stronger barring formed by thick and black bars while juvenile feathers show narrower and less well defined bars, often in a slightly more irregular pattern. [CS00450]

1cy October. Many young birds, like this one, show a moult contrast in the TT. The inner two are moulted post-juvenile while the longer is still juvenile (like adjacent S6). Note the more diffuse and irregular dark pattern on the long juvenile T. [CP41538]

1cy September, showing moult contrast. Inner shortest T is post-juvenile, albeit rather difficult to see in the photo. Note the (very slightly) less warm brown colour ans different structure/wear in the tip compared to the still juvenile longer two with more diffuse and irregular markings. [CR96129]

Troglodytes troglodytes - autumn