Troglodytes troglodytes - spring

Eurasian Wren

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.

2cy April. GC1-4 are juvenile in contrast to post-juvenile inner GC5-10. Note (slight) difference in basic colour, tendency to white tip and more distinct dark markings in the post-juvenile feathers. [CP42749]

2cy April. GC1-7 are juvenile (warmer brown, slightly longer and more worn) in contrast to the post-juvenile inner GC8-10. [CP44015]

2cy March. A slightly odd bird showing post-juvenile GC1 and GC4-6, contrasting to adjacent juvenile GC. [CV55244]

2cy April. GC1-7 are juvenile (warmer brown, slightly longer and more worn) in contrast to the post-juvenile inner GC8-10. [CP44015]

3cy+ April. All GC uniformly adult type. Typical black subterminal band and black distinct markings in centre. Although there is a subsequent variation in pattern between inner and outer feathers, there is no sudden change forming a contrast, as in 1cy birds. [CN89745]

3cy+ May. All GC uniformly adult type. A less distinct pattern, but still different from typical juvenile GC. Note the whitish tips to GC and black subterminal bars. [CN94653]

2cy April. Juvenile GC are warm brown with rather diffuse pattern. All visible GC are juvenile as well. [CP44015]

2cy March. A slightly more contrasting pattern than the previous, but still rather diffuse dark markings. [K8E6310]

3cy+ March. Adult PC are slightly colder brown and well marked with distinct black pattern. [CP42520]

3cy+ April, showing variation. [CP42747]

2cy March. The two inner TT are moulted post-juvenile, contrasting to the longest one that are still juvenile. Note difference in wear and in pattern with more distinct bars in the post-juvenile feathers and more irregular and diffuse markings on the juvenile one. [K8E6310]

2cy March, showing variation with all three TT juvenile (warm brown with diffuse dark markings, and rather worn). [CT49742]

3cy+ March. Uniform adult TT with distinct dark marking forming bars. [CT49133]

3cy+ April, showing variation. [CP42747]

2cy April. SS and PP show a typically juvenile pattern with rather diffuse and slightly irregular dark bars in the outer vanes. The pale spots on outer PP on this bird are paler than in average 2cy but still slightly 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 show spots that are less easy to count. Note that GC1-4 are juvenile. [CP42749]

2cy April. A rather extreme juvenile bird showing very sparsely and illdefined barred wing. The pale spots on PP are buffish and very washed out. [CP42830]

3cy+ April. A uniform wing with prominent barring formed by well defined black bars. Pale spots on outer vanes of PP are numerous and whitish (contrasting to the blackish feathers). [CN89745]

3cy+ May. A uniformly wing, but barring is less prominent than on average adult. The white spots on PP are numerous and prominent on the blackish feathers. [CN94653]

2cy April. A dominantly post-juvenile tail but with unmoulted juvenile R1 (both sides). Uppertail-c are probably lost and replaced recently. [CP42830]

2cy April, showing variation. R1-2 (both sides) are juvenile while the rest of the tail is post-juvenile. Note warmer brown colour in juvenile feathers and more distinct barring on the post-juvenile ones. [CP44015]

3cy+ April. A uniform post-breeding tail. Note the distinct and rather coarse black barring. [CN89745]

3cy+ May. A uniform post-breeding tail showing dark bars that are distinct but slightly narrower than average. [CN94653]

More Troglodytes troglodytes:

Ageing autumn
Moult

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