Sylvia communis - spring

Common Whitethroat / Törnsångare

AGE - BEST CRITERIA:

Individual differences in wear and moult as well as prolonged and/or differentiated periods of moult during the winter makes ageing rather problematic at times, especially during late spring and early summer when also adult birds are more worn. Moult contrasts may be present anywhere in the wing and tail in both age classes, and should be examined carefully. It is important to rembember that the differentiated moult periods during winter creates contrasts within the pre-breeding feather generations, and separating post-juvenile feathers from early pre-breeding feathers may be impossible. Colour of iris is more difficult to use since many 2cy birds have developed a more adult like coloration.

2cy:
  • Juvenile PC are usually very worn and faded pale brown, but more well kept birds are not always easy to separate from adult. Note that a few birds may show single or some fresh PC, moulted during the winter symmetrically to their PP (see below).
  • Juvenile PP (as well as SS) are generally more heavily worn and bleached brownish, looking rather dry.
  • Some birds (according to Jenni & Winkler [1994] 24% of all 2cy but only c. 3% of 3cy+) moult single or several PP during winter. The portion may be lower in Scandinavian birds, but the difference in frequency between 2cy and 3cy+ is worth noting. (Conversely, birds that have renewed all six SS during the winter seem to be more common among 3cy+ than among 2cy, but this is of little practical use).
  • Any unmoulted juvenile GC still present is very worn, with a dry pale brownish centre and very worn pale buffish edge. In order to separate it from worn post-juvenile GC, make sure to check structure (less dense vane in the juvenile feather). According to Jenni & Winkler (1994), only 16% of the spring birds retain some juvenile GC.
  • Most birds include all three tertials in the pre-breeding moult, but a few may still show a single bleached and very worn juvenile tertial.
  • Quite a few birds still show single or several retained juvenile RR, but birds with no juvenile RR present are common as well. Any juvenile RR is recognized by being very worn, often even broken, and faded pale brown, preferably more worn (and less dense in structure) than other worn generations also present among the RR
  • The colour of the iris have developed and is generally adult like. According to Karlsson et al. (1985) the most developed (most vividly orange) iris of 2cy still does not reach the most developed 3cy+, but this is difficult to judge without direct comparison of several individuals. Note also that there is an average sexual difference with more males showing the warmer orange irises.
3cy+:
  • Adult PC are generally more dense and in better condition, but differences are not always obvious.
  • Post-breeding PP and SS are generally better kept and slightly darker and denser than juvenile ones, but a few are more worn and less easy to judge.
  • Like in 2cy, quite many birds show single or some (or even all) fresh pre-breeding SS. Some individuals also show some renewed PP, but this seems more uncommon than in 2cy.
  • GC, tertials and tail often show moult contrasts between any of worn post-breeding, intermediately worn 'early pre-breeding' and fresher 'late pre-breeding' feathers, impossible to use for aging since the corresponing generations are also shown by 2cy as well.
  • Regarding the colour of the iris, see above under 2cy.
2cy (male) June. Juvenile PC are usually less dense, much worn and faded pale brown, but more well kept birds are not always easy to separate from adult. Note the three juvenile and worn alula feathers. [1ES24778]
2cy June, showing variation. This bird shows a worn juvenile longest alula while the inner two are less worn pre-breeding. [1ES24779]
2cy May, showing variation in the juvenile PC. Note the fresh pre-breeding longest and shortest alula, while the central feather is more intermediately worn. This feather i too dense and fresh to be a juvenile, but separating post-juvenile feathers from early pre-breeding ones are difficult (and not necessary, since it is only the presence of juvenile feathers that are relevant for the ageing). [1ES23782]
2cy May, showing variation. Here, all three alula feathers are pre-breeding and, hence, are not useful for ageing. Note also that the outermost two PC are more fresh and have been renewed during the winter (as have their corresponing PP). Such moult patten may be found in both age categories, but seem to be more common in 2cy. [1ES24625]
3cy+ (female) May. Adult post-breeding PC are generally slightly more dense and in better condition than juvenile, but differences are not always obvious. In 3cy+ birds the alula may show a moult contrast between fresh late pre-breeding or intermediately worn early pre-breeding or post-breeding feathers, but these contrast re not useful for ageing since also 2cy often showns the corresponing generations. [1ES23855]
3cy+ May, showing variation. [1ES24681]
3cy+ (male) May, showing variation. [1ES23852]
3cy+ (female) May, showing variation. Note the moult contrast between the innermost fresh late pre-breeding alula feather and the more intermediately worn post-breeding or early pre-breeding feathers (not useful for aging). [1ET28146]
2cy (male) June. Juvenile PP (as well as SS) are generally more heavily worn and bleached brownish, looking rather dry. Note also the innermost S6 have been renewed, probably in an early pre-breeding moult. [1ES24782]
2cy June. Note the rather extensive renewal of remiges in this bird, including SS3-6, PP2-3 and P5 (still growing). [1ES24785]
2cy (male) May. Note the wear in tips of PP (as well as fresh pre-breeding S1 and S5). [1ET28113]
2cy (male) May. Another 2cy showing some moult of remiges. Here, P2, P5 and SS5-6 have been moulted, probably in an early pre-breeding moult. [1ET28181]
3cy+ May. Adult post-breeding PP and SS are generally better kept and slightly darker and denser than juvenile ones, but a few are more worn and less easy to judge.Tips of PP are generally more fresh and darker/denser than in 2cy (but a few are more worn and less easy to judge). Note the fresh pre-breeding P3 and S6. [1ES23766]
3cy+ May, showing variation. Note the renewed PP2-4 and SS5-6, probably from early pre-breeding moult. [1ES23773]
3cy+ (male) May, showing variation. Not easy to tell from this image alone, but it seems that all SS1-6 may have been renewed during early winter. [1ES24626]
3cy+ May, showing variation. Note pre-breeding renewal of all SS1-6. [1ES24681]
2cy (male) May. Most importantly, GC7 (just visible) is juvenile and very worn. Remaining GC are a mixture of late pre-breeding (GC10) and early pre-breeding or post-juvenile, not relevant in the ageing process. According to Jenni & Winkler (1994) only 16% of 2cy birds retain some juvenile GC. [1ET28181]
2cy May. This bird only shows GC that are not useable for ageing (prebreeding/post-breeding generations), but note that two juvenile (very worn) MC are present in the central part of the MC row. [1ES23782]
3cy+ (male) May. GC consist of pre-breeding/post-breeding generations, not relevant for ageing. [1ES23852]
3cy+ (female) May. Another adult showing GC of pre-breeding/post-breeding generations, not relevant for ageing. [1ET29600]
2cy (male) May. Longest tertial are recognized as juvenile on heavy wear and less dense structure. Inner two feathers are pre-breeding/post-juvenile, not relevant for ageing. [1ES24753]
2cy May, showing a set of tertials that seem to be from early (the central feather) and late pre-breeding moult, not usable for ageing. [1ES23853]
3cy+ (female) May, showing pre-breeding and/or post-breeding tertials, not useful for ageing. [1ET29600]
3cy+ (male) May, showing uniform pre-breeding tertials. [1ET28118]
2cy May. A bird showing a worn (but relatively well kept) juvenile tail, apart from both R1 that are likely post-juvenile. [1ES23799]
2cy May, showing a dominantly worn juvenile tail, apart from R2 (both sides) that are pre-breeding, and R1 (both sides) that are either post-juvenile or pre-breeding. [1ES24708]
 
2cy May. Tails may be rather difficult to assess (esp. separation of early pre-breeding and post-breeding/post-juvenile generations, which all can be rather variable in wear). However, separating the mentioned generations is not necessary - it is only the presence of juvenile feathers that help the ageing process (proves the bird as 2cy). In this bird, right R2-3 are juvenile, while the rest are likely pre-breeding. [1ES24663]
2cy May, showing early/late pre-breeding/post-juvenile RR, not useful for ageing. [1ES24597]
 
3cy+ May, showing early/late pre-breeding/post-juvenile RR, not useful for ageing. [1ES23772]
3cy+ (female) May. Adult birds never show presence of juvenile RR and, hence, the tail can never prove a bird as 3cy+. As in most other 3cy+, this one shows a mixture of early/late pre-breeding/post-juvenile RR. [1ET29629]
 
2cy (male) May. The colour of the iris of 2cy have developed during the winter and is generally adult like. The most brightly orange irises may perhaps be shown by 3cy+ only but this is difficult to judge without direct comparison of several individuals. Note also that there is an average sexual difference with more males showing the warmer orange irises. [1ET28182]
2cy May, showing variation. [1ES23799]
 
3cy+ (male) May, showing variation. [1ES24626]
3cy+ (female) May. Showing variation. [1ES23873]
 
More Sylvia communis:
Sexing spring
Ageing autumn
Sexing autumn
Moult
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