Saturday, 29 November 2014

Ringing session with a twist.

I am not sure where to start with this post as today's ringing session didn't turn out anything like I expected it to. There have been a dwindling number of thrushes moving over Billinge and I didn't catch a single bird on my last outing (27th) so I thought I would be declaring autumn passage over in this part of the world by today. It has been a fantastic autumn for Redwings at the site but the southward movement of Redwings that had arrived further north had to end some time. However this morning bucked the trend with Redwings passing overhead and calling through the darkness while I was putting up the nets.

Redwing 29/11/14
I had been joined by Paul who had expressed an interest in training to ring but I had warned him that I didn't expect to catch much if anything. Well the birds decided to make a fool out of me with a few Redwings dropping in almost straight away. It wasn't just Redwings as there was a continental Song Thrush amongst them in one of the later catches. A flock of at least 40 Fieldfares narrowly missed the nets and a couple of smaller parties also flew over adding to the migratory feel of the morning. It wasn't just a case of birds moving from their roosts to feeding sites either as the movements went on too far into the morning for that.

Continental Song Thrushes, like this bird, are more olive grey from the nape to the upper tail coverts compared to the British race which have warm brown upperparts.

Continental birds are also much whiter underneath with much less buff on the breast.
We didn't just catch thrushes as there were a good number of Yellowhammers, Chaffinches and Goldfinches about, along with a few Reed Buntings. The real twist to this tale came in the form of one of the Yellowhammers that had an overgrown and twisted upper mandible. Buntings have slightly odd looking bills to start with as the upper mandible is smaller than the lower so it doesn't take much of a deformity to make them look really odd and this was no small deformity. It was a first year bird so this overgrowth had only developed in the last 4 or 5 months or thereabouts. It never ceases to amaze me how birds adapt and survive with such deformities and it was clearly doing quite well as it had a healthy weight (25.1g) and its plumage was in excellent condition.

Yellowhammer with a twist.

It must be really difficult for this bird to pick up seeds.

There was a coating of soil on the end of the upper mandible which suggests it scrapes the ground when the bird is feeding.

The plumage was in pristine condition so it must be managing to preen well enough.

Normal Yellowhammer for comparison.

Paul releasing his first Yellowhammer.
The final surprise was finding a Kestrel in one of the nets when I went to take them down. Kestrels are ever present at the site and are more common than Sparrowhawks but this was the first I have caught there.

Kestrel 29/11/14

Kestrel 29/11/14
Ringing totals (with retraps in brackets): Redwing 14; Song Thrush 1; Yellowhammer 10 (1); Chaffinch 3; Goldfinch 2; Reed Bunting 1 (1); Bullfinch 1; Kestrel 1.

Reed Bunting 29/11/14

Friday, 21 November 2014

Redwings: coburni v iliacus

I think I was a little too cautious in my post 'More of the same' (link here) with regard to the photograph of a Redwing that showed characters of the Icelandic race 'coburni'. I suggested its appearance possibly fell a little short of the mark but if anything fell short it was my experience of birds from the Icelandic population (nil up to then). I caught another dark and heavily marked bird yesterday and it stood out as much if not a little more than the previous bird did which prompted me to reconsider that earlier note of caution. It also prompted me to do some homework and I have been trawling the internet looking at photos of the races and reading up on the subject. I am now certain that yesterday's bird and the previous bird (caught 16/11/14) are Icelandic Redwings.

Birds of the Icelandic subspecies (T.i.coburni) are marginally larger and darker than nominate birds from northern Europe (T.i.iliacus) but only around 14% of Icelandic birds have longer wing lengths and therefore relatively few can be separated on size. Both birds had wing lengths that fell in the upper part of the overlap in the wing length ranges with yesterday's bird being 127mm (right on the upper limit) and the first bird had a wing length of 124mm. Published wing length ranges vary depending where you look but I have gone with 126/127mm as being the upper limit for nominate birds largely based on a paper that considered occurrences on Heligoland (Germany) which can be found here.

In terms of appearance 'coburni' is described as being slightly darker and are generally more heavily marked and having looked at a lot of images of both races there appears to be less overlap in appearance than there is in size. However I do feel there was a bias towards showing obviously darker birds amongst the examples of migrant 'coburni' photographed outside Iceland which is only to be expected when the separation of the races is not always clear cut. Another feature for separating the races is the colour of the legs and feet which are dark horn brown in 'coburni' and pinkish-flesh in 'iliacus' and this was very obvious and can been seen in many of my photographs.

Redwing of the Icelandic race 'coburni', Billinge 20/11/14
The following series of photos shows the same bird with a fairly typical bird of the nominate northern European race 'iliacus' that was caught the same day and photographed in similar conditions. 

'coburni' above and 'iliacus' below.
'coburni' left and 'iliacus' right.
'coburni' above and 'iliacus' below.

The following images are of the previous Icelandic bird caught on 16/11/14. On looking at these images again I don't know why I was cautious about fully attributing it to the Icelandic race. 

Redwing of the Icelandic race 'coburni', Billinge 16/11/14

Redwing of the Icelandic race 'coburni', Billinge 16/11/14 (same bird but appears to have a slightly paler throat and upper-breast from this angle).

Redwing of the Icelandic race 'coburni', Billinge 16/11/14

...and here is a collage showing how it compared with a lightly marked nominate bird caught the same day.

'coburni' left and 'iliacus' right.
The final image below shows a collage of both Icelandic birds with what I consider to be a heavily marked nominate bird (lower right) and a more typical nominate birds (top right). Although you can't really see much of the upper parts you can see enough to appreciate how much darker both Icelandic birds are. The upperparts of the Icelandic birds are what I would describe as a dark olive earth-brown whereas the nominate birds are more of a mid toned warm brown. The other thing to note in this image are the feet; darker horn brown coloured in the Icelandic birds (left) and pinkish-flesh coloured in the nominate birds (right). The strength, size and colour of the markings on the underparts largely speak for themselves but there is a little more variation in them.

Upper left 'coburni'; lower left 'coburni'; upper right 'iliacus'; lower right 'iliacus'.

If you are interested in comparing other images of migrant 'coburni' photographed in the UK examples can be found  here (Bardsey),  here (North Ronaldsay),  here (Fair isle),  here (Norfolk).

For images of 'coburni' taken in Iceland you can view images taken by Jakob Sigurdsson here and here. Other images by Gudmunder Geir's can be found here.

It is also worth a second look at the 'We Bird North Wales' blog post on this subject here.

Tuesday, 18 November 2014

Black - caps and heads

There have been a few bits of interest in the last couple of days. A brief early morning ringing session at Billinge yesterday produced 2 Blackcaps and third was probably present. The Blackcaps were heard calling in the half light, just after I had set up, and must have dropped in overnight or that morning. They are most likely to be birds coming in for the winter given the date but as this has been an exceptional autumn in many ways I wouldn't like to say for sure. I haven't seen any Blackcaps there for 4 weeks with the last being ringed at the site on 20th October. The only other birds caught yesterday morning were 2 Redwings and a Blackbird although a female Sparrowhawk did escape from one of the nets just before I packed up and may have been responsible for keeping some birds away.

A photo of the second of the 2 male Blackcaps. A smudgy shot because of the low light.
This afternoon I nipped across to Orrell Water Park to check out the Black-headed Gulls for rings as a colour-ringed Black-headed Gull had been seen there on Sunday. I am currently in the process of obtaining the ringing details of that bird for the person who found it but I wanted to see if it was still present or if there were any others including returning birds. I didn't see the colour-ringed bird amongst the 70 or so Black-headed Gulls that were there but I soon saw a first winter bird with just a metal ring. I took a series of photographs and luckily it walked around enough for me to photograph the ring all round and get the full ring number. It was a British ring and I will post details of where and when it was ringed when I receive them in a few weeks time.

New kid on the block.
I thought that was the only ringed bird and I had run out of bread to attract them when I noticed an adult that was also wearing a metal ring. Luckily it turned to threaten another bird as I rattled off a series of shots so I was fairly sure I had got the full number. On reviewing the results on the back of the camera I quickly realised that I recognised the ring number. It was the German ringed bird, 1A141745 from the Hiddensee ringing scheme, that has wintered at Orrell Water Park for much of the previous 2 winters. I recorded it 14 times from 27/10/12 to 26/01/13 and 13 times from 27/10/13 to 26/01/14. It is interesting that the first and last recording dates in both of those winters were the same and it was an accurate reflection of its presence over those winters. I haven't been checking out the gulls as often this time so it could have been back for a while.

It was nice to see that this German ringed bird had returned for its 3rd winter. This bird was originally ringed as an adult on 29/04/12 at Bohmke und Werder, Mecklenburg - Vorpommern, Germany, 1,102 km to the east (see map below).

 Recovery map for  Black-headed Gull IA141745 

Sunday, 16 November 2014

More of the same.

Although autumn migration has slowed down in the main there is still a good southward movement of thrushes and Fieldfares in particular. At Winter Hill, a well watched vis mig site 20km to the north east of Billinge, just short of 10,000 have been recorded moving south over the week including 1,465 today. At Billinge numbers of Fieldfare moving south were in the high hundreds on Monday and in the mid hundreds yesterday and today but I have been ringing on part of the site that has quite narrow viewing opportunities and observations were largely restricted to birds passing directly overhead so many others will have been missed. Smaller numbers of Redwings have also been moving south with 120+ on Monday and similar numbers yesterday and today. There haven't been been any obvious migrant Blackbirds during the week but there is still the odd migrant Song Thrush moving through with the Redwings.

Although Fieldfares were the most numerous by some margin it doesn't make them any easier to catch.

The number of Redwings ringed at Billinge this autumn now stands at 650.

This Redwing stood out as being a quite dark and is fairly close in appearance to some examples of the Icelandic race 'coburni' although possibly still falls a little short. A good series of images comparing the races can be seen here.
Other passage migrants have been limited to a few Siskins, Goldfinches and Chaffinches along with the occasional Brambling and Lesser Redpoll but some of these may have just been the local movements of wintering birds. Similary it is getting hard to sort out what Woodpigeons are doing with some seemingly moving north, others going south and flocks that are simply moving between roosts and feeding sites. On the other hand some winter visitors are still arriving and I logged my first Woodcock of the autumn for Billinge yesterday and it was followed by a sighting of two today. Lastly, there is still a little trickle of Goldcrests with one or two new birds being ringed on each visit. The number of Goldcrests ringed at the site this autumn has now reached 312 which is far more than I ever expected or have experienced at any other site in the area. 

There was no problem ageing and sexing this Lesser Redpoll as an adult male but they remain few and far between.

Ringing Totals
Monday 10th:  Redwing 14; Song Thrush 1; Lesser Redpoll 2; Goldcrest 2.
Saturday 15th:  Redwing 15; Song Thrush 1; Fieldfare 1; Goldcrest 1.
Sunday 16th:  Redwing 14; Fieldfare 3; Goldcrest 2.

Sunday, 9 November 2014

Slowing down

There has been a marked slowing down in visible migration over Billinge in the last couple of days and it is beginning to feel a bit more like winter. A few thrushes were still on the move yesterday and today with Redwings in high double figures and Fieldfares in the low hundreds on both days. Finch movement has all but stopped with just a few Chaffinches and Goldfinches going south. Lesser Redpolls have never really got going this autumn and are still very scarce with none seen yesterday and only one today. Goldcrest numbers have also dropped off with only one or two now being encountered.

Fieldfares and Woodpigeon
I tried getting some shots of birds flying across the face of the moon this morning but I always seemed to be ringing a bird when the best opportunities came or at least that is my excuse.

The number of birds ringed has reduced, as would be expected with fewer birds passing through, but the first Fieldfare of the autumn was caught yesterday and followed by another two today. It is always good to catch a Sparrowhawk as they don't find their way into the nets all that often so I was pleased to catch a male yesterday and doubly so to catch a different male today. The combined ringing totals for yesterday and today were: Redwing 15; Fieldfare 3; Goldcrest 2; Sparrowhawk 2; Lesser Redpoll 1.

Although Fieldfare are more numerous at the moment they are much more difficult to catch than Redwings.

Sparrowhawk number 1

Sparrowhawk number 2, a much more richly coloured bird.

It is that time of year when I start to check out the gulls on the local park to see if any are wearing rings. I didn't see any ringed gulls there yesterday but a fine drake Mandarin seems to have taken up residence.

The weather for next week looks quite interesting and there could still be a few more thrushes to come on the back of the south easterly winds that have been forecast. I may be being too optimistic about the forecast and the birds but I will be out and about now and again to find out.

Sunday, 2 November 2014

more Redwings

There was another good movement of thrushes over Billinge this morning, much as expected, with Redwings being the dominant species. Birds were calling overhead through the darkness when I arrived at 6am to set up the nets but the bulk of the movement that could be seen was from shortly after first light to an hour after sunrise with flocks dropping in or passing over every few minutes. It was hard to gauge how many birds went through in that short time as I was kept busy ringing but I estimated it was close to 1,000 Redwings. There weren't many Fieldfares but two sizeable flocks of about 100 birds each went through.

The final wintering destination of this Redwing could be France or even further south in Spain and Portugal. 
After the initial rush a few flocks of Redwings continued to move through occasionally but all movement seemed to have stopped by 10:30. The morning saw another 55 Redwings caught and this session brought the total ringed over the last 3 weeks to 552 and there could be a good few more to come. There should still be some birds that have yet to work their way south from the northern isles and mainland Scotland and the weather looks favourable for another arrival of thrushes on Wednesday or Thursday, around the time of the full moon. If there is another arrival of thrushes it is likely to be mainly of Blackbirds and Fieldfares but a good number of Redwings could also be involved.

Only 2 other species were ringed this morning and these were Goldcrest and Coal Tit. The 9 new Goldcrests brought the number ringed at the site this autumn to a fairly impressive 297. Observations alone would not have revealed anything like that number of birds moving through the site nor the rate of turnover. Hopefully there will be some recoveries of these birds in due course to indicate their origins and destinations. At the other end of the scale the single Coal Tit brought the number of that species ringed at the site to a much more modest 22.

Goldcrest. There has been an almost continuous turnover of these birds at the site over the last two months.
Coal Tit

A very smart little bird.

Saturday, 1 November 2014

Mostly thrushes.

Many of the thrushes that arrived on the east coast in large numbers on Thursday (one account here) worked their way across the country and produced a good movement over Billinge yesterday and today. Large numbers of Redwings and Fieldfares flew south and probably numbered in the low thousands of each over the two days. There were few Song Thrush, Mistle Thrush and Blackbirds mixed in but I was too busy ringing much of the time to do any detailed counts.

Migrating Redwings. You really have to see a large movement of thrushes to appreciate the spectacle.
Fieldfares and Redwings heading south.
The ringing totals for yesterday weren't as high as might have been expected given the volume of birds passing through. This was probably due to the large numbers of Fieldfares as they are much less inclined to drop in than Redwings and many of the Redwings opted to continue on with the Fieldfares as a result. Ringing totals for 31/10/14 (retraps in brackets): Redwing 33, Song Thrush 2, Blackbird 1, Goldcrest 13 (1), Long-tailed Tit 4, Coal Tit 1.

This Common Buzzard was also heading south and could have been a migrant rather than a local bird.
The ringing totals for this morning saw a marked improvement over yesterday's and that was almost certainly because there were less Fiedfares going over and many of the thrush flocks were just comprised of Redwings. Ringing totals for 01/11/14: Redwing 64, Song Thrush 2, Blackbird 2, Goldcrest 4, Long-tailed Tit 2, Chiffchaff 1, Lesser Redpoll 2, Yellowhammer 2.

Redwing 01/10/14. Looking its best against a blue sky.
Quite a few of the Redwings have been carrying passengers in the form of ticks.
Song Thrush are under recorded as a migrant as they can be hard to pick out amongst the hoards of migrating Redwings. I have ringed 40 at Billinge since 7th October and that will be a fraction of the number that have moved through over that period. I have seen at least double the number I have ringed and many more will have slipped through unnoticed.
Two stunning adult male Yellowhammers found their way into the nets today.
Migrating Lesser Redpolls continue to be few and far between.
This late Chiffchaff was the first for a while. It was quite fat and presumably a departing summer visitor rather than being one that may winter.
Large numbers of thrushes arrived in some of the northern isles yesterday (link here) so there should be plenty more moving south over the next day or two. Anyway I will be up early in the morning to find out.