Saturday 26 July 2014

24th to 26th July

The weather has been favourable for ringing over the past few days and the fine conditions with light winds at either end of the day have helped produce some very good catches. I have managed to fit in 2 evening and 2 morning sessions over the past 3 days and was tempted to put in that amount of effort because of the good weather and number of birds that have been about.

There appears to have been a bit of an influx of Willow Warblers which has supplemented the locally bred birds and resulted in a good number being caught. This influx of Willow Warblers has coincided with arrivals on Bardsey Island over the same period and suggests there has been a large scale movement down the west coast. Willow Warblers have declined markedly in recent years and have been outnumbered by Chiffchaffs in the ringing totals for quite a few years now so it is good to see them show some signs of a resurgence. Evidence of migration also came in the form of a Reed Warbler which was well away from the nearest breeding habitat along with 2 adult Garden Warblers which were similarly on the move.

A freshly moulted adult Willow Warbler (left) and juvenile right showing the difference in the colour of the underparts. Adults are generally much whiter below whereas juveniles have extensive lemon yellow underparts.

Juvenile Reed Warbler 26/07/14

Adult Garden Warbler 26/07/14. 

Garden Warblers don't breed at any of my ringing sites and only occur as a
scarce and less than annual passage migrant.
Goldfinch family parties are starting to merge into flocks and although most of the birds caught have been juveniles there have been a few adults which I have photographed to add to my sexing guide update or may even result in a new post. Being able to confirm the sex of the birds from the presence of a good brood patch or the shape of the cloaca has been really useful; I now have some photographs that show how much overlap there is in the plumage features of the sexes especially with regard to the extent of the red on the face.

Female left and male right. The slight difference in colour cast was caused by the lighting conditions with the female caught on a dull evening and the male caught in bright morning sunshine. The female clearly has an extensive red face mask that extends well behind the eye and bit further than that of the male. There is not a lot of difference in the lesser coverts although the fringes of the male's lesser coverts were golden (brownish-yellow) and the fringes of the female's were brown and a bit more extensive. In terms of plumage features the nasal hairs stand out as being the most different with the female's being white and the males being black.
There were roughly between 100 and 300 Swallows using the roost but some birds only dropped in late and from some height making numbers hard to gauge. These late arrivals were presumably birds that had been on the move and were looking for a roost to join.  At the other end of the scale in terms of numbers I am still catching the odd wandering juvenile Willow Tit with another ringed this morning. All in all it has been a very interesting and productive few days especially when you consider that I only used 2 nets for each session.

Ringing Totals 24th to 26th July (retraps in brackets).
Willow Warbler 32 (3)
Chiffchaff 10 (1)
Blackcap 10
Whitethroat 5
Garden Warbler 2
Reed Warbler 1
Goldcrest 3
Goldfinch 24
Linnet 8 (1)
Chaffinch 5
Reed Bunting 2
Yellowhammer 1
Swallow 41
Blackbird 3
Long-tailed Tit 2
Great Tit 1
Willow Tit 1
Total 151 (5)

Tuesday 22 July 2014

House Martins no fluke

I went back to the Billinge site this evening with a view to catching some more Swallows at the roost and to see if any House Martins were roosting with them. While I was putting up the first net a juvenile Sedge Warbler appeared in the willows beside me. This was a first for the site, for me at least, and well away from the nearest breeding population so obviously a bird on passage. It made its way into the net soon after I had set up along with 5 Willow Warblers, a Chiffchaff , a Blackcap and 2 Goldfinches, not a bad start.

Juvenile Sedge Warbler 22/07/14
There were more Swallows around than last night with an esimated 400 present and there were at least 2 Sand Martins and 4 House Martins with them. The conditions were perfect and the first Swallows were caught well before the light started to fade. A Sand Martin was also caught along with 2 House Martins showing that the 2 caught last night was no fluke. The final tally of Swallows for the evening was 54 and brought the total ringed at the roost over the last few weeks to 386.

Juvenile House Martin 22/07/14

Juvenile Sand Martin 22/07/14

Juvenile Swallow 22/07/14

Ringing Totals for 22/07/14

Swallow 54
House Martin 2
Sand Martin 1
Sedge Warbler 1
Blackcap 1
Willow Warbler 5
Chiffchaff 1
Goldfinch 2
Total 67

Warbler fest and House Martin surprise

I made a half-hearted attempt at getting up early yesterday morning and set the alarm for 05:30, after couple of snoozes I eventually got up and went to the site near Billinge and put up a couple of nets. It was a glorious morning with a light breeze and little in the way of cloud cover but on the down side the clegs and horse flies were out in abundance and certainly made their presence felt, literally.

It seemed fairly quiet at first with few birds calling but a steady stream of birds were caught and ringed over the next few hours. In fact it turned out to be a really good session considering I was only using 2 nets totalling 32m in length. Warblers made up the bulk of the 44 birds caught and included 14 Blackcaps, 7 Whitethroats, 9 Willow Warblers and 4 Chiffchaffs. Best of the rest were a Yellowhammer, a Willow Tit and 5 Goldfinches. The Willow Tit was a  retrap and one of the Goldfinches was already ringed but was one I had originally ringed in my garden, 2 km away, last December.

This juvenile Whitethroat had almost completed its post juvenile moult although most had only just started.

All the Blackcaps caught were juveniles like this one and had only just started their post juvenile moult so will be around for a few weeks yet.

Most of the juvenile Willow Warblers were close to completing their post juvenile moults like this bird and could be migrating south before the end of the month.

This adult female Chiffchaff  looks rather scruffy in its heavily worn plumage but had just started its complete moult. It will replace all of it feathers over the next few weeks before migrating.

Adult female Yellowhammer.

This male Goldfinch was originally ringed in my garden on 01/12/13.
As the wind remained light I went back to another part of the site in the evening to see if the Swallows were still roosting in the willows. I set up the usual 2 nets and waited for the birds to arrive. Before the Swallows started to gather another 5 Willow Warblers, 2 Chiffchaffs and a Whitethroat were added to the day's warbler total. Swallows started to arrive as usual but in smaller numbers than there had been last week when up to 1,000 were present in the roost, around 150 Swallows eventually gathered and 28 were caught before they finally settled.

I had noticed a few House Martins amongst the Swallows just before they settled so I played House Martin song on one of the MP3 lures and 2 juveniles were caught almost immediately. This was the first time I have caught House Martins in a roost situation and it will be interesting to see if I can repeat this at this site. Very little is actually known about the roosting habits of House Martins, there is some suggestion they roost in trees and also that they roost on the wing. Both may be true at times but it is really difficult to establish what they actually do and nobody really seems to know for sure. It is certainly one of those mysteries I would like to help unravel.

A poor photo of one of the juvenile House Martins. Where do they roost?

Ringing totals for 21/07/14 with retraps in brackets.
Chiffchaff 6
Willow Warbler 12 (2)
Blackcap 14
Whitethroat 8
Goldfinch 4 (1)
Yellowhammer 1
Willow Tit (1)
Robin 2
Blackbird 1
Swallow 28
House Martin 2
Total 78 (4)

Wednesday 16 July 2014

16th July 2014

I have been very busy in one way or another over the last week or so and haven't had the time to post on the blog before now. Today wasn't much different really, I was out this morning for a brief ringing session at the Billinge site before rain and domestic duties stopped play. I went back this evening to see if the Swallows were still roosting in the willows and only got back late as a result. This site is turning out to be really productive and the Swallow roost has been the most unexpected find so far. There were around 500 Swallows in the roost tonight and I caught and ringed 51 (all juveniles) which was a comfortable number to deal with. I have now ringed 196 Swallows and 1 Sand Martin since finding this roost on 25th June.

Juvenile Swallow

This juvenile is just starting to get a few darker red feathers on the throat.

Ringing Totals for 16/07/14
Swallow 51
Chiffchaff 7
Willow Warbler 6 (1)
Blackcap 4
Whitethroat 2
Linnet 1
Willow Tit 1
Total 72 (+1 retrap)

Tuesday 8 July 2014

Birds nest revisited

I have been following the progress of a few nests recently including a Sparrowhawk nest that was shown in an earlier post. There were 5 chicks which is a fairly typical brood size and when they were ringed I found that 3 were males and 2 were females. Sparrowhawk chicks can be sexed on leg and foot size from about 9 days of age but females are starting to become much bigger overall by that age too. It is good to report that they have been making good progress as can be seen in the images below.

The Sparrowhawk nest was found 24/06/14 when the chicks were about a week old and it was quite crowded then.

When I returned to ring them on 30/06/14 it really was a full nest.

The chick was sexed as a male and fitted nicely in my hand.

This female chick was much more of a handful than the male above.

I returned on 02/07/14 to check them from a distance and they were clearly doing well.
I had been worried about this nest being disturbed or worse still the chicks being stolen because of its location.

I went back this afternoon and this young male was standing proud on the edge of the nest. He has lost most of his down and could leave the nest by the end of the week.
I will go back again to check that they have fledged successfully and when they have finally left I will also check the nest for pellets to see what prey they have been eating. In the past I have found the remains of some interesting prey in Sparrowhawk nests including Swift, House Martin, Sedge Warbler and Brown Hawker Dragonfly but young Blackbirds and Starlings are often the most common prey items. If I do find anything of interest I will report it in due course.

Friday 4 July 2014

Sexing Goldfinches: summer update

My previous post on this subject has proved to be the most popular of my offerings by far; it continues to receive a good number of page views and seems set to remain the most popular post on this blog for a long time to come. The traffic sources indicate that it has been frequently viewed by those with an interest in keeping Goldfinches as cage birds in addition to bird ringers which it was primarily aimed at. There is clearly a lot of interest in this subject which is testimony to the difficulty that can be encountered in sexing a fair proportion of Goldfinches using plumage features alone. 

The fact that bird keepers can have difficulty telling the sexes apart is interesting as they have the ability to observe the birds they want to sex over a period of time whereas ringers only have a very brief opportunity when the bird is ringed and examined prior to release. Most confusion for ringers occurs in autumn and winter and appears to involve more first year birds than adults but that is when most Goldfinches are caught for ringing and first year birds often make up the bulk of those catches. The perceived greater difficulty in telling the sexes apart in first year birds may largely be a function of the sample sizes involved and may not be a real difference between the different age groups. 

It doesn't get any easier the more birds you catch either and this has been echoed by other ringers that have got in touch with me. The more birds you handle the more variation you get to see in the extent of the red face mask, appearance of lesser coverts and colour of nasal hairs and the combinations of those plumage features. The one thing that really hinders the refining of the sexing criteria and learning how best to apply them for me is the lack of known sex birds to test them with. I have previously said that I rarely catch Goldfinches during the breeding season when the presence of an incubation patch or cloacal protuberance can be used to confirm the sex of a bird. However I have put in a bit more effort in recent weeks and have managed to catch a few adult Goldfinches. Unfortunately I haven't caught anywhere near enough to see the full extent in plumage variation that is likely to exist but I still think it is worth showing images of some of the birds caught recently.

Confirmed male Goldfinch ringed 15/06/14:
The extensive and bright red mask on this bird is a good example of what a well marked male can look like.

The bird does have a few small white feathers on the front of its forehead otherwise the nasal hairs are black. In my experience it is not uncommon for male Goldfinches to have a few small white feather on the front of the forehead.

The lesser coverts on this bird have quite broad tips to the innermost feathers in particular, however they are gold coloured fringes rather than brown. This bird supports my view that any bird exhibiting such gold coloured (brownish yellow not brown) fringes to the lesser coverts, no matter how extensive, will be a male.

Confirmed female Goldfinch ringed 26/06/14:
The red mask is much less extensive on this bird and only just extends beyond the eye and combined with the greyish white nasal hairs (note some are worn or missing) make this a text book female. This bird also has some small white feathers on the front of the forehead like the male above.

The lesser  coverts on this bird are text book female too and form a brown patch at the shoulder.

The obvious incubation patch on this bird confirmed the sex as female.

Confirmed female Goldfinch ringed 30/06/14:
This bird has a more extensive mask compared to the previous female and clearly extends beyond the eye although nowhere near as extensive as the first male. The nasal hairs are mainly black or greyish black and there are no small white feathers to the front of the crown. The mask is more orange red than red but the colour of the mask can vary in shade and intensity and there is much overlap between the sexes.

The lesser coverts are similar to the previous female although the brown fringes are not quite as broad. However they still give the impression of a brown shoulder patch.

This bird also had a very good brood patch and confirmed the sex as female

Confirmed male Goldfinch ringed 30/06/14:

The red mask extends beyond the eye but not much further than the female above but the red is more crimson. The nasal hairs are clearly all black.

The lesser coverts have a mixture of narrow and broader brown fringes and some of the inner lesser coverts have brown bases. They are probably best described as intermediate between the text book examples of male (mainly black) and female (mainly brown). 

Confirmed male Goldfinch ringed 30/06/14:

This bird has a crimson mask that extends behind the eye. There is even red streak that extends a long way behind the eye where the red meets the black of the crown.

The lesser coverts are mainly black but all have well defined narrow brown fringes and this is quite common in males. It is fairly uncommon to find males with all black greater coverts in my experience although I have caught a few.

If you are wondering I didn't photograph the cloacal protuberance in any of the the males because I was ringing on my own and I just found holding the bird and blowing back the feathers and pointing the camera in the right place far too difficult but the sex of each male was confirmed in that way.  I hope to catch a few more adult Goldfinches this month while there is still the opportunity to confirm their sex and before they start to moult and if I do there may be another post on this subject later this month.
A further update can now be found by clicking here.