NOTES ON AGEING AND SEXING (under development)

This new section of the website contains some items previously included in the 'blog' and, going forward, will include notes and articles on ageing and sexing birds in the hand. Links will be available from the 'Index' shortly.

Redstart (07/04/11)

A second year male Redstart was a very welcome surprise for Kevin, amongst this morning's catch of usual early returning migrants, such as Chiffchaff, Willow Warbler and Blackcap. The Redstart was aged on the old brown-edged greater coverts.

Second year male Redstart with old brown-edged greater coverts

Brambling (18/03/2011)

A very pleasant morning at Ringinglow produced some interesting birds. Ten Siskin, including a control (below), were complemented by three Brambling and three Great-spotted Woodpeckers, all of which drew blood.

A controlled Siskin

A pair of Brambling caught together provided an opportunity to compare the differences between the two sexes and to look at the ageing criteria. Most Brambling have unmoulted greater coverts after the post juvenile moult, making 1y/2y spring birds easy to age. The male below was easily aged as a (5), clearly showing 4 old greater coverts.

Male Brambling

2y male with 4 OGCs

In the female the contrast, although present, is more difficult to pick out. The best ageing feature in this bird was the worn, brown alula feather.

Female Brambling

Note the retained alula feather, indicating a 2y bird.

Nuthatch and Green Woodpecker (28/10/2010)

I got an e-mail from a ringing friend yesterday, who finished by saying that a mutual friend had ringed a Cetti's Warbler and a Common Redpoll this week at his site at Wintersett Reservoir. By way of reply, I wrote that although I was ringing in the morning, I didn't expect to ring either of those species (although stranger things had happened). Sure enough, I didn't see or hear either of the aforementioned species, let alone ring one! Nevertheless, a pleasant morning ringing with a good mix of finches, 5 Yellowhammer and 5 Redwing was made even better with 2 species that I rarely encounter at my sites.

The first was a Nuthatch, which was caught with some Long-tailed Tits and may have been associating with them. Although Svensson states that there are no plumage differences, many first years can be aged by a moult limit in the median coverts. This bird was aged as a 3, because the outer median coverts are clearly greyer and more worn than the inner replaced median coverts which are blue. The final net round produced the star bird of the morning, an adult female Green Woodpecker. The bird was aged as an adult based on the criteria in the non-passerine guide. Sean Ashton.

Nuthatch

There is a clear moult limit in the median coverts, with the outer older ones being grey with noticeably worn tips

Green Woodpecker

The bird is easily sexed as the male has a red moustache, making this a female

The tertials lack any prominent white barring

The primary coverts, although not completely black had rounded tips and obvious green edges

Lesser Redpoll (16/10/2010)

As well as Meadow Pipits, one species that we catch in reasonable numbers at the moorland sites is Lesser Redpoll. 2008 was a bumper year with over 2000 ringed by the group.

Like several of the finch species, this bird can be aged by differences in the shape and degree of pointedness of the tail. In general, at this time of year the adults (Euring age 4) have more rounded tips to the tails, whereas the tails of first year birds (Euring age 3) are more pointed and worn. However, this characteristic is not reliable for all birds, and examination of the feather tracts in the wings can help to separate intermediate birds. First year birds often show contrast in the median and greater coverts. The photographs below illustrate some of the key points for ageing at this time of year. Sean Ashton.

A typical adult tail with well rounded tips to all the feathers.

The rump of the bird above, an adult male

The breast of the adult male above. Birds aged as 4 with no red on the breast, flanks or rump can be sexed as females

Tail of a first year bird with pointed tips to the tail feathers, and the tail feathers are already showing signs of wear

The wing of the same bird. This bird was easily confirmed as a first year as there is a clear contrast in the median coverts, with the 2 outermost visible juvenile feathers being a lot paler and more worn

The breast of the bird above. At this time of year, first year birds with no, or very little red on the breast, flanks or rump have to be left unsexed

Another first year tail. A bit of a give away this one, but the whole bird should always be examined. Adult birds can grow tails with large fault bars, if the tail is accidentally lost

The wing of the bird with the fault bar in its tail. This bird has had a very limited postjuvenile moult, with only the innermost GC (slightly longer and deeper buff fringes) being of adult type. The tips of the paler juvenile GCs are showing signs of wear.

Ageing Treecreepers (16/10/2010)

This is an updated version of a previous article with improved photographs. A photograph of an adult bird will be added when we catch one! Treecreepers are not the easiest birds to age according to plumage (Svennson, 1992) although he mentions a method of ageing based on the size and shape of the pale tip on the 3rd outermost primary covert. However, he also claims that this method needs more testing.

In an excellent article, Suorsa and Hakkarainen (2007) presented their findings of testing this method of ageing, and demonstrated that it is a useful field character for ageing Treecreepers. The authors showed that the pale tips on the outer webs of the outermost primary coverts on young birds are larger and more drop shaped than those of adults.

Treecreeper wings showing the large pale tips on the longer primary coverts. Note how the tips on the inner primary coverts are less conspicuous.

The pictures above, of two different birds caught at Ringinglow this morning, show these teardrops on the primary coverts well. The prominent pale spot on the longest primary covert clearly identifies this bird as 1st year, rather than an adult. It is important to look at the outermost primary coverts, as the pale tips on the inner primary coverts can be inconspicuous like those on an adult. Sean Ashton.

References

1. Identification Guide to European Passerines, Svennson, 1992, p 247

2. Ageing and Sexing in the European Treecreeper, Suorsa and Hakkarainen, Alula 4, 2007 pp 146-150.

Ageing Blackcaps (22/09/2010)

This is a very interesting time of year for ringers but it can be a bit tricky. With both adult and juvenile moult coming to an end, it is so important to check all ageing criteria on birds caught.

This 4 male Blackcap was ringed in the Shire Brook Valley on 22/09/10. At first glance, the pointed tail indicated a juvenile bird (code 3); the 4th and 5th tail feathers are more broad and rounded but mixed moult of the tail is not uncommon. However, on closer inspection the tail feathers appeared relatively broad and it can be seen on the photos below that P1 and P2 still have a small amount of sheath on them, as did the innermost secondaries. Kevin Bower.

The central tail feathers are pointed, but relatively broad.

The 2 outermost primaries still have sheath at the base

Willow Warblers (01/08/2010)

The photos below show an adult (4) and a juvenile (3) Willow Warbler. Notice how yellow the juvenile appears compared to the adult. Kevin Bower.

3J Willow Warbler

4 Willow Warbler

Aberrant Reed Bunting (05/06/2010)

The pictures below, kindly supplied by the Stanford Ringing Group, show a female Reed Bunting showing some male colouration on it's head pattern. Although the bird is somewhat duller than a full male, it could catch out the unwary. The bird was originally ringed as a 3J on 02/08/2008 and retrapped as a 4F with a BP on 27/06/2009, before being caught again today. The bird had a brood patch and a wing of 75mm, which although not completely out of range for a male bird is much more typical of a female. The breeding plumage of certain bird species is controlled by hormones, with females deprived of their sex organs adopting male plumage. Therefore, might this bird's plumage be due to a hormone imbalance? Further information would be gratefully received. Geoff Mawson.

Female Reed Bunting with male characteristics. Photos courtesy of Mike Haig

Juvenile Siskin (01/05/2010)

These pictures are of a juvenile (3J) Siskin ringed this morning at Uppertown, the first fledged Siskin ringed by the group this year. The buffish plumage tones are clearly visible. George Briggs.

Juvenile Siskin

The first Snipe of the year at Blackburn Meadows (10/10/2009)

A calm, clear morning with a slight mist rising and a beautiful sunrise helped to compensate from being dragged from my bed at 4 am to put some nets up in the dark for Snipe. Kevin and myself were joined by 4 other group members and the nets were duly erected with hopes of catching Reed Bunting and Snipe, our target species for the morning. Our efforts were well rewarded and we were able to count 2 snipe and 8 Reed Buntings amongst the morning's total of 60 birds.

It was a morning for renewing acquaintances with old friends as both the Snipe were retraps and we caught a Reed Bunting that had been ringed 4 years previously, but had not been seen in the intervening years. The retrapped Snipe allowed us to examine the ageing criteria for adults, proposed in a recent article in 'Ringing and Migration' based on a contrast in the humeral coverts. This was present on both birds, and a photo of one is included below.

Note the faded covert, indicative of an adult bird.

Sean Ashton and Kevin Bower

Tree Pipits (23/08/2008)

On Saturday 23/08/2008, the weather forecast was for virtually no wind, so Kevin and myself decided to have a go at ringing Steve's Meadow Pipit site above Agden, in order to target Tree Pipits.  We arrived early and were rewarded after about half an hour with a promising looking bird.  Although neither of us had ringed a Tree Pipit before, after carefully checking Svennson, the bird was definitely identified as one and aged as a 3 based on a step in the median coverts.  Another bird soon followed, also a juvenile, but still no Meadow Pipits, although a few were flitting around.  A smattering of Willow Warblers and Wrens kept us occupied for the next hour and we ringed two more Tree Pipits, again first year birds, before leaving.  These birds were aged on the tertials (see photos below).  Kevin says that although obviously an excellent site for Tree Pipits, it may do well for Meadow Pipits later in the year, if properly developed!!

Tree Pipit

Tree Pipit ID - Note the fine streaking on the flanks, and the short (8mm), obviously curved hind claw.  These features separate Tree Pipit from Meadow Pipit.  The other useful ID check is the wing length; the wings of all 4 of the birds we caught were 89 mm, longer than Meadow Pipit wings.

Meadow Pipit hind claw - note the obviously staighter and longer hind claw of the Meadow Pipit, typically ranging between 11 and 14 mm.

Tree Pipit wing. With Tree Pipits, primaries 2, 3 and 4 are all the same length, but 5 is shorter (see above).  Meadow Pipits have primaries 2,3,4 and 5 of equal length (see below for comparison).

Meadow Pipit wing

Note the contrast between the adult warm buff fringed tertials and the unmoulted juvenile tertials with very pale edges.

All the tertials on this bird were of the juvenile type.

This is a photo of the wing of the first bird we caught that was moulting its median coverts.  There is a clear colour difference between the inner moulted MC and the older outer ones, although it does not show quite so well on the photo. Sean Ashton.