Eurasian Sparrowhawk
AGE – BEST CRITERIA:
NB: The text below is based on autumn birds. At Ottenby, much fewer birds are trapped during spring and, hence, we have many gaps in our photo collection of spring birds. However, since the winter moult in this species is absent (or very restricted), the characters mentioned are valid also in spring. Just add some wear and change the age codes accordingly (1 cy to 2cy, 2cy+ to 3cy+ and so on).
Up to four age categories are discernible, depending on the extent and timing of the post-br moult of the individual. In 1cy, entire plumage juv, fresh and without any moult contrasts. The plumage is brown with rufous fringing on many feather tracts. Older age classes show a grey-blue plumage with no rufous fringing, and most birds show a uniform ad plumage with no moult contrasts (though the regular moult sequence in this species sometimes creates the false impression of contrasts). Other adult birds show true moult contrasts in the wing and can then be categorised as 2cy or 3cy+ based on the retained feathers from the previous generation: If the retained feathers are juv, the bird is in its second plumage (2cy). If the retained feathers are a (worn) ad generation, the bird is in its 3rd or further plumage (3cy+). But it is very important to beware of ’false moult contrasts’ created as a result of multiple moult centres in the SS. Determining whether an ad feather is from an earlier stage of the current moult cycle or from the plumage of the previous year requires a bit of care.
At Ottenby, of the adult (i.e. non-1cy) autumn birds trapped (n=126), 29% showed some retained juv feathers and could be aged to 2cy, whereas 12% showed two ad generations and could be aged as 3cy+. The remaining 59% had a uniform post-br plumage and could only be aged as 2cy+.
Iris colour changes gradually with age and may provide some support to plumage characters, but note a high degree of individual variation.
1cy:
2cy+:
2cy:
3cy+:
1cy female, August. Uniform juv plumage, fresh and with no signs of past or ongoing moult. Upperparts brown with rufous fringing. [6224911]
1cy male, October. Young birds sometimes have a paler cinnamon plumage. The plumage of most young males and females closely resemble each other. [5130468]
2cy+ female, October. Cold grey on upperparts. The blue tones are less pronounced on females than on males. Overall lacking rufous fringing. Females almost always lack the rusty orange tones in cheeks and breast of ad males. [6224980]
2cy+ male, October. Bluish-grey on upperparts, lacking rufous fringing. Ad males show rusty orange tones in cheeks, throat and breast. [5130463]
1cy female, August. Young birds have brown 'heart-shaped' spots on underparts, often more pronounced in males. [6458902]
2cy+ female, September. Ad lack the 'heart-shaped' spots of young birds and instead show clean barring on underparts, brown, grey or orange. [6440270]
1cy male, October. Uniform and fresh juv wing, with no signs of moult. Rufous fringing in wing coverts. Overall brown base colour. [5130468]
1cy female, August. Some individuals show reduced and paler fringing in the wing, and a more grey-brown base colour, but never as grey as in ad. [6458902]
2cy+ male, October. Whole plumage ad type. No rufous fringing and a deep grey-blue coloration. [5130402]
2cy+ female, September. Whole plumage ad type. Ad females tend to show a less blue coloration, but never as brown as in young birds. [6440270]
2cy+ female, September. Some ad can show fringing in the wing coverts (note not only the white fringing in the GC and MC of this individual but also the rusty fringing of the smallest LC). [6440203]
2cy+ female, September. Due to moult timing and sequence, some individuals show considerable differences in wear and bleaching in their plumage, particularly the SS, which may be erroneously interpreted as two different generations. In this individual, for example, S4 looks fresher and bluer than S5. This, however, perfectly matches with the moult order of the SS: S4 is one of the last feathers to be moulted while S5 is one of the first, hence why they look so different (see ageing criteria for more information). [6224992]
2cy female, September. An example of an individual showing retained juv feathers: S8 (brown in colour, worn edges, different barring pattern) and several LC (brown in colour, very worn, with the buff edges mostly worn away, except for in a couple of protected feathers close to the body). [6224995]
2cy female, September. A bird in active post-br moult showing many still retained juv feathers: 4 SS (showing much a higher level of wear and a difference in length and barring pattern to the ad SS), as well as some MC, many LC, P1, body feathers, etc. Note that due to timing and sequence, the moult has also created striking bleaching differences between the ad SS of the same generation (for example, compare S5 to S6). [6440274]
2cy female, September. A 2nd year bird that has completed the post-br moult, showing very few retained juv feathers (only a couple of inner MC), recognisable by their brown ground colour and, in some, a rufous edge. Some feathers not showing a rufous edge can be attributed to wear. [6458911]
2cy female, September. A closeup of the previous bird. [6458911]
3cy+ male, November. An example of an individual showing retained feathers of a worn ad generation from the previous plumage cycle: S4 and S7. We can tell that there is a true moult contrast towards S4, and not just a 'false contrast' produced by moult timing, by the fact that S4 is usually one of the last feathers to be moulted and hence should look even fresher than its surrounding SS if it was from this year's moult cycle. Furthermore, it is clearly older than the innermost primary, which is typically the oldest feather in the wing (i.e. the first one to be moulted in the cycle). [5084800]
3cy+ male, October. Another example, with several retained ad feathers: S3-4, S6-10, one GC and multiple MC and LC. Keep in mind that many of these feathers are likely not properly arrested, and may well be in the process of being moulted over the autumn. [5130467]
1cy female, September. A typical juv tail. Note the rufous edging of the upper tail-coverts. [6224922]
2cy+ male, October. A typical uniform ad-type tail. [5130463]
2cy female, September. Individual in active post-br moult. The brown and worn RR are juv feathers and the light grey and slightly worn RR (R1+R6) are post-br feathers from the current moult cycle, but moulted earlier in the spring or summer. [6440274]
2cy female, September. A 2cy bird after the post-br moult, showing single retained juv upper tail-coverts, recognisable by their brown ground colour and, in some, a rufous edge. Some feathers not showing a rufous edge can be attributed to wear. [6458911]
1cy female, August. Typical bright yellow iris of a 1cy. [6458902]
1cy male, October. Showing variation. [5130468]
2cy female, September. Females are slower than males to develop colour in the iris and may never develop red like in males. 2cy females tend to have a yellow iris like that of juv, sometimes with small traces of orange. [6224977]
2cy male, September. Males are quicker than females to develop colour in the iris. 2cy males tend to have a slight orange tinge, but are generally still quite yellow. [5130486]
3cy+ female, September. The iris in ad females often have orange tones but still with an overall yellow impression. [6222295]
3cy+ male, November. Older males can show intense red. However, orange tones are the most common case, and perhaps an overall yellow impression is not impossible for this age category. [5142502]
3cy+ female, August. An older adult female with considerable orange tones in iris, likely more than usual for this age/sex category. [6188783]
3cy+ male, November. An older ad male showing striking red tones in the iris. [5084800]
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