Icelandic Redwings & Sparrowhawks

I only had time for a brief ringing ringing session at Billinge this morning but it turned out to be well worth the effort. A total of 12 Redwings, 3 Goldcrests and 1 Sparrowhawk were caught in little more than an hour which isn't bad going for mid November, especially as only 2 nets were used. The Sparrowhawk was a new female and another that failed to do the usual last minute climb out of the net and escape trick. However, it was the fact that 3 of the Redwings were stand out examples of the Icelandic race, coburni, that made it particularly worthwhile.

The upperparts of Icelandic Redwings tend to be a shade darker overall but it is the much heavier (blotchier) and more extensive streaking of the underparts, dark brown legs and toes, and well marked under-tail coverts that make them really stand out from continental birds (nominate race iliacus).

Icelandic birds average bigger too but in my experience wing length is of limited value as most will fall in the overlap between the two races. This bird had a wing length of 126.5 mm and was noticeably bulkier than the iliacus that were caught at the same time. However, it still falls within the overlap as iliacus can have a wing length of up to 129 mm (yes 129 mm and I have caught one that big myself) although most publications used by ringers only give an upper limit of 126, 127 or 128 mm. 

November and mid November in particular seems to be a good time for Icelandic Redwings at Billinge; my first were recorded in mid November 2014 (link here)

Today's 1cy female Sparrowhawk was the 4th female of the autumn.

While on the subject of Sparrowhawks I managed to get a photograph of a cracking little male that caught a Goldfinch in the garden a few days ago. It was already wearing a ring and I was able to read part of the number which suggests it is one that I ringed at Billinge in autumn 2015 but that is as far as I could narrow it down.

Male Sparrowhawk 12/11/2018

Easterly winds have set in and are forecast to continue for a good few days so it will be interesting to see if they bring anything unusual this way. They could pep up thrush movements initially, if nothing else. I just hope they are not too strong and give me the chance to get some nets up.

Billinge 29th October 2018

I wasn't sure what to expect after my week away, more so given the clear and frosty start, but it ended up being quite a good session for late October. There were a few thrushes moving early on resulting in 9 Redwings, a Fieldfare, and a Blackbird being caught but they soon fizzled out. There wasn't much in the way of visible migration, once the thrushes had stopped, but a Crossbill and a few high flying Siskins were noted along with a small movement of Woodpigeons. The most interesting sighting came mid-morning when a Woodcock (my first of the autumn) landed on the track near to where I was stood, it took a few steps and then fanned its tail and raised it over its back in the manner of a Black Grouse but then it noticed me an flew off. I have never had such a good view of a Woodcock before or seen one tail fanning so that was a nice bonus.

The nets continued to produced a few birds after the initial rush of thrushes and the final total of 36 new birds and 1 retrap was quite a good result, all things considered. There were no surprises but 10 Goldcrests was a good number and a flock of Long-tailed Tits helped bulk the numbers too, while a female Sparrowhawk caught in the last round was a great way to end the session.

Ringing totals (retraps in brackets) for 29/10/2018 were: Sparrowhawk 1; Coal Tit 2; Blue Tit 2; Great Tit 1; Long-tailed Tit 7 (1); Goldcrest 10; Robin 1; Blackbird 1; Fieldfare 1; Redwing 9; Lesser Redpoll 1.

This 1CY female Sparrowhawk was in one of the nets when I went to take them down at the end of the session. I have done quite well for catching female Sparrowhawks this autumn as they are usually very good at getting out of mist-nets.

 

Sparrowhawk double

It had to be a shorter session than usual at Billinge this morning because I had an appointment to go to but it turned out to be interesting nevertheless. There weren't many thrushes moving but over 2,000 Woodpigeons were counted going south by 9:00am (per CAD). A single Brambling was the first of the autumn and another or the same was heard again later. There were no warblers, not even a Chiffchaff, but Goldcrests found their way into the nets at regular intervals and a total of 13 were ringed. A couple of Sparrowhawks livened things up with a 1cy male being caught first and a 2cy female being caught in the same net an hour later. Catching 2 Sparrowhawks in the same session doesn't happen very often but the 3 previous occasion it has happened have all been in mid October like today's double act. The lively theme continued when a rather feisty Jay was caught and it did its best to take lumps out of me, as they usually do. The last net round produced a group of 5 Lesser Redpolls and, interestingly, 4 of the 5 were adult males which continues the predominance of adults in the Redpolls caught so far this month.

1cy male Sparrowhawk

1cy male Sparrowhawk

2cy female Sparrowhawk

The female Sparrowhawk had an unusual and very hard accretion on the tip of one of its claws. I have never seen anything like this before and have no idea what could have caused it..

Ringing totals (retraps in brackets) for 15.09.18 were: Sparrowhawk 2; Jay 1; Coal Tit 2, Blue Tit 1; Great Tit 1; Goldcrest 13; Blackbird 1; Song Thrush 3 (1); Bullfinch (2); Lesser Redpoll 5. Total 29 new birds and 3 retraps.

Billinge: 5th & 10th September 2018

September is a month when autumn migration is normally in full swing and even if one species doesn't deliver another usually does. However, this September is starting to look very different to those of the past 4 years at Billinge and although there is still time for things to change things don't look very promising at the moment.

5th September 2018
A morning that got off to a good start with a Song Thrush caught in the first net just as the last guy rope was being tied off. September sees British Song Thrushes starting to move and the first continental migrants arriving with this bird likely to be one of the former. After that it was generally a lacklustre session with the numbers bulked up by a few too many tits. If I had to pick a highlight it would be the capture of the first 4 Meadow Pipits of the autumn although 4 is a relatively poor total for this date in September. The biggest news, if you can call it that, was the near absence of Goldcrests with only 2 caught. Goldcrests usually start to move through the site in good numbers from the start of September so a total of 2 is well below the norm of the past 4 years.

Meadow Pipit 05/09/2018

Totals for 05/09/2018 were: Blue Tit 11; Great Tit 6;  Willow Warbler 2; Chiffchaff 6; Blackcap 4; Goldcrest 2; Song Thrush 1; Meadow Pipit 4; Chaffinch 1; Linnet 3.

10th September 2018
If the session on the 5th fell short of what I have come to expect from the site in September this one was even more disappointing. The near absence of Goldcrests of the 5th became a total absence with none being caught, seen or even heard. To give that some context last September saw 21 ringed on the 1st, 17 ringed on the 10th September and a total of 77 over the first 10 days. In 2016 it was a similar picture with 50 ringed over the first ten days of the month and no blank sessions. It is starting to look like Goldcrests were hit really hard by spell of severe cold weather back in March.
It is getting a bit late for Willow Warblers so the capture of 2 was noteworthy but the near absence of Chiffchaffs was far more unusual with none caught and only 2 heard all morning. Chiffchaffs numbers normally peak in September and a capture total in low double figures should have been on the cards. The quiet theme was also reflected in the visible migration with only a few Meadow Pipits moving. It was the quietest I have known the site to be in September by some margin and it is to be hoped the rest of the month doesn't carry on that way.

Totals for 10/09/2018 (retrap in brackets) were: Sparrowhawk 1; Blue Tit 4 (1); Willow Warbler 2; Blackcap 2; Dunnock 1; Meadow Pipit 7; Chaffinch 2.

One of the Blackcaps caught on the 10th was still largely in juvenile plumage which is suggestive of some very late breeding.

The last bird caught on the 10th was this juvenile female Sparrowhawk.

Starling Down

A thud against the window drew my attention to a commotion in the garden late this afternoon and when I looked out a young male Sparrowhawk was trying to pin down a Starling on the garden path. I think the Sparrowhawk had caused the Starling to veer into the window and had grabbed it on the rebound before taking it down on to the path. The Starling did its best to try and get away and it took the Sparrowhawk a good 2 or 3 minutes to get it fully under control.

I grabbed the camera and took a few photos through the window but it was very overcast and the light levels were really poor. Even at ISO 1600 I could only get a shutter speed of 1/50th of a second so most of the images were a blur from the birds' movements and an element of camera shake. I only shoot JPEGs so that doesn't leave much scope for fancy editing but most couldn't have been salvaged even if they had been taken in RAW format as they were far too blurred and or out of focus. However, there were four images that didn't turn out too bad with a bit of basic tweaking and as long as you don't look at them too closely.

The Starling was one of my colour-ringed birds but I didn't manage to get the ring number before the Sparrowhawk carried it away which is a really unfortunate. I am fairly sure it will have been a first-year bird as most of the Starlings that have been visiting the feeders recently are birds that were ringed as juveniles in the spring and early summer.

9th October: thrushed with success.

I had high hopes for this morning as large numbers of thrushes (especially Redwings) arrived along parts of the east coast yesterday and decent movements were also recorded at some of the Pennine vis mig sites. Good numbers are often recorded at Billinge the day after such arrivals and movements so the prospects for this morning looked good. I was so eager to find out I got up when the first alarm went off, was out of the house at 05:30 and had set 4 nets at Billinge by 06:30.

A few Redwings and Song Thrushes were heard calling as dawn approached but not as many as expected and a Song Thrush was the only bird caught prior to sunrise. However, a few small flocks of Redwings and one or two Song Thrushes started to arrive shortly after sunrise and the flocks of Redwings generally got larger as the morning went on. Birds were coming and going in various directions but the majority seemed to appear from the east or south east and while some flocks continued west or northwest others turned and headed south. Around 650 Redwings must have moved through over the course of the morning but it's always hard to keep track of numbers when you are busy ringing. The number of Song Thrush on the move was even harder to gauge and the 12 that were recorded is likely to be well short of the true figure, especially as that number includes 7 that were ringed. As for other thrushes there were a few more Blackbirds around and 4 Fieldfare seen heading northwest late in the morning was a bit of a surprise as it is relatively early date for that species.

Song Thrush

Redwing

When there are plenty of thrushes around they usually attract a few predators and today was no exception. A juv male Sparrowhawk was seen several times before it eventually found its way into one of the nets. A little while later a juv female Sparrowhawk was caught which is a bit more unusual as females often manage to climb out of nets due to their much larger size.

1cy male Sparrowhawk

1cy female Sparrowhawk. If looks could kill this one's would.

There weren't many finches moving and only 1 Lesser Redpoll was caught. Surprisingly, it was another that didn't have a red coloured poll, the amber poll on this individual being a bit brighter than the one shown in my last post.

Lesser Redpoll

The morning may have started slowly but Redwings eventually came through in good numbers and accounted for 38 of the 65 birds ringed. Ringing totals for 09/10/17 were: Sparrowhawk 2; Goldcrest 9; Great Tit 2; Coal Tit 1; Chiffchaff 1; Blackbird 3; Song Thrush 7; Redwing 38; Chaffinch 1; Lesser Redpoll 1.

Other sightings of note included: 320 Pink-footed Geese heading east; 4 Ravens (2 pairs) heading south; 2 Swallows (1 south and the other hanging around feeding); 3 Crossbills heading NNE.

Tree Pipits come to the fore

The last couple of days have seen a marked increase in the number of Tree Pipits on the move at Billinge with a minimum of 10 recorded yesterday and 30+ today. It is not easy to keep track of numbers when you are busy ringing and it doesn't help that many don't call when flying over so I am sure I will have missed a few on both days. The increase in numbers on the move was also reflected in the ringing totals with 5 ringed yesterday and another 12 today.

Today's total of 12 ringed is the 2nd highest day total for the site and has only been bettered twice; on 14/08/14 and 17/08/15 with 13 ringed on both of those dates. Half of today's Tree Pipits were adults which is quite unusual but it gave me an opportunity to photograph some of the plumage features used when ageing birds in autumn. More information on ageing Tree Pipits can be found here, here and here (the latter being the best in my opinion) They are fairly straightforward to age once you get your eye in and fully understand their moult, especially if you get to handle quite a few, but I would say they are not as easy to age as Meadow Pipits.

S881408 1cy Tree Pipit. The fringes of the unmoulted median and greater coverts are quite worn and very pale (a cold bleached straw colour) when compared with those of the adult below and is probably from an early brood. It should be noted that the margins of median coverts and greater coverts of juveniles from later brood are less worn and can be more olive-buff like adults.

S881401 Adult (2cy+) Tree Pipit. Adults have fresher and more olive-buff fringed median and greater coverts.

S881401 2cy+ Tree Pipit. This adult was interesting in that it hadn't replaced 2 lesser coverts which stand out as being very worn and bleached.

S881401 2cy Tree Pipit. A closer look at those retained lesser coverts. They are very worn and have a narrow and bleached white fringe and shouldn't be mistaken for retained juvenile feathers. Birds like this can easily trap the inexperienced and unwary.

S881401 2cy+ Tree Pipit tail. Fresher and generally more pointed than the typical juvenile tail except for the central pair which are usually a bit more rounded when fresh compared to the central pair of a worn juvenile (see tail of S881408 below) but be aware some juveniles replace the central pair of tail feathers.

S881408 1cy Tree Pipit wing. This bird hasn't replaced any of the median coverts, greater coverts or tertials so there are no obvious moult limits to make ageing easy. Even the outer row of lesser coverts are all old. You just have to rely on wear and colour with birds like this.

S881408 1cy Tree Pipit tail

S881410 2cy+ Tree Pipit tail.

S881410 2cy+ Tree Pipit wing.

Ringing totals for 20/08/17 were: Sparrowhawk 1; Goldcrest 3; Blue Tit 9; Chiffchaff 6; Willow Warbler 15 (1); Blackcap 1; Whitethroat 2; Treecreeper 1; Wren 1; Tree Pipit 5; Chaffinch 1; Linnet 2; Goldfinch 2.

Ringing totals for 21/08/17 were: Chiffchaff 2 (1); Willow Warbler 6 (1); Whitethroat 1; Nuthatch 1; Tree Pipit 12; Chaffinch 4; Bullfinch 2.

Juvenile male Sparrowhawk 20/08/17

Juvenile male Sparrowhawk 20/08/17

Nuthatch 21/08/17

Billinge 10th August 2017 - more on Willow Warblers

Well, buy me a flat cap and call me Victor because I am bringing up the subject of Willow Warblers and age ratios again. Another ringing session at Billinge on the 10th resulted in a catch of 42 birds that included 11 Willow Warblers, 7 of which were adults. I didn't know what to expect given the complete absence of juvenile Willow Warblers in the previous day's catch but I didn't think adults would outnumber juveniles by almost 2:1. It increasingly looks like Willow Warblers have had a very poor breeding season and I can't see the situation improving unless there have been a lot of successful late broods and those juveniles have yet to come through.

Eye colour can be used to help age Willow Warblers in autumn. Adults have a brown eye approaching chestnut colour like the bird on the right whilst the eye colour of juveniles is much duller and greyer like the bird on the left. I have not used this feature prior to this autumn but it appears to be very reliable from what I have seen so far and is well worth using in conjunction with the usual plumage features. It wasn't easy to photograph but is fairly easy to see in the hand with the naked eye, although some may find use of a low magnification hand lens helpful.

Willow Warblers are generally single brooded and although they are amongst the first of the summer visitors to arrive they have a pretty tight schedule as autumn migration peaks towards the middle of August and the adults also have to fit in a complete moult. The schedule is so tight adult Willow Warblers may start to moult before they have completed breeding, they also moult quite quickly and they often start migrating before the moult is complete. That tight schedule limits the opportunity for late broods (be they second broods or repeat nesting attempts following earlier failures) which means the chances of there being a surge in juvenile numbers from them is really quite low.

While there is evidence that climate change is causing some summer visitors to arrive a little earlier and depart a bit later than they used to it doesn't mean the duration of stay of individuals is getting significantly longer nor does it mean the timing of migration has changed significantly for the bulk of the population. Willow Warblers that arrive a little earlier may simply be amongst the first to leave and those that stay later are more likely to be juveniles and they may also be compromising their survival chances by a later departure. It certainly doesn't look like climate change is extending the breeding season for Willow Warblers or likely to lead to an increased occurence of second or late broods.

Whilst climate change may be extending the spring and autumn periods the major impact on Willow Warbler productivity is caused by the weather during the breeding season, and the levels of rainfall in particular. It is not just the amount of rainfall that matters but also its intensity that can make all the difference when it comes to breeding outcomes and more intense rain is one of the consequences of a warming climate. Met Office statistics show June 2017 has been amongst the wettest on record, with the UK as a whole having 50% more rainfall than average. Whilst North Merseyside wasn't one of the worst affected areas in terms of increased rainfall it did experience some intense downpours that could have led to increased nest failures and increased mortality of recently fledged young. Parts of northern England and southern Scotland have received more than twice the normal June rainfall and that could have had an even bigger impact on productivity in those regions. 

Juvenile Willow Warbler 10/08/17.
This recently fledged juvenile had only just started its post-juvenile moult and must have come from a late nesting attempt. Their fluffy juvenile plumage probably doesn't provide much protection from prolonged or intense periods of rain.

So it seems to have been a wash out for Willow Warblers this year and while there may be some regional differences I suspect the overall picture will show productivity is below average and well below that of last year. The higher number of adults caught in July may have been due to a high incidence of failure late in the nestling stage as that wouldn't have left enough time for those adults to make another breeding attempt. Such failed breeders may have started migrating a little earlier as a result.

Other ringing highlights from the 10th were: a young male Sparrowhawk, the first of the autumn; another 5 new Goldcrests bringing their August total to 14 and autumn total to 33 which is well up on last year; 2 Tree Pipits from at least 12 seen which is the first double figure movement of the autumn and fairly typical for the date.

This young male Sparrowhawk had the odd remnant of down on the tips of  some of the feathers of the mantle.

I love Tree Pipits.

Ringing totals for 10/08/17 were: Sparrowhawk 1; Goldcrest 5 (1); Blue Tit 4; Great Tit 2; Coal Tit 1; Long-tailed Tit 4; Chiffchaff 3; Willow Warbler 11; Blackcap 1; Whitethroat 2; Wren 1; Song Thrush 1; Tree Pipit 2; Goldfinch 1; Yellowhammer 1; Reed Bunting (1).

Crawford: 12/12/2016 and wing moult in first year Blackbirds

I don't know what is happening with thrushes and Redwings in particular but there seems to more nocturnal movement than is usual at this time of year, especially given the absence of any cold weather. Some large nocturnal movements of thrushes were noted at Spurn Bird Observatory towards the end of last week and some of those continued in daylight hours at Spurn but more so at Sunk Island. These unexpected movements attracted the tongue in cheek comment 'Mild weather movement?' in the list of sightings for 9th December on the Spurn Bird Observatory website.

I have heard Redwings overhead well before first light on numerous occasions recently and that happened again when I was loading the car to go ringing on the 12th. When I got to Crawford I heard the calls of a few more Redwings going over in the dark in the short time it took me to set up the line of two nets. Whatever the reasons are for these movements it seems to translate into more Redwings being in the area and good catches at dawn, although they are remarkably inconspicuous during rest of the day. The net result, no pun intended, was that I caught another 16 Redwings on the 12th which took the number ringed so far this month to 131. It also took the number ringed since early October past the 1100 mark and to 1110 to be precise. How long these nocturnal movements and dawn catches will continue is anybody's guess but now that I have mentioned them they will probably come to an abrupt end. I will find out soon enough as I hope to get out to Billinge and/or Crawford later this week.

This is the one thousand, one hundred and ninth (1109) Redwing ringed this autumn/winter. Yes I know it is an odd number but the light levels were too low when number 1100 came along.

Whenever there are a good number of thrushes around one or more Sparrowhawks are never too far away and that was also the case on the 12th. Their presence sometimes reduces the catch of Redwings, especially when they make frequent sorties, but that is quickly forgotten about when one ends up being caught in one of the nets. Sparrowhawks have a bit of a reputation for getting out of nets, especially the larger females, but I have been lucky enough to catch 10 since early October with 5 of them being females.

2nd year Female Sparrowhawk. It is bigger than it looks in this photo. 

Blackbird was the only other species handled with 8 new birds and 2 retraps being caught. One of the first year males was particularly interesting because it had replaced some of its secondary flight feathers in both wings, which first years don't normally do. There was some asymmetry to the moult but it certainly didn't appear to be due to any accidental loss of feathers.

Eccentric moult in 1CY Blackbird LK6922 caught at Crawford 12/12/2016

A bit like the stockamsel plumage Blackbirds that I wrote about in my last post this was the second first year male Blackbird to come my way that had undergone a partial moult of the flight feathers. The first was a Blackbird that I retrapped in the garden on 22nd November, it had been ringed as a juvenile on 7th August so wasn't from a particularly early brood but it definitely made it a bird of UK origin. The moult of this bird was far more extensive and involved some of the primaries, primary coverts and secondaries, and all of the greater coverts, tertials of both wings, although there was some asymmetry. The entire tail had also been replaced.

Left wing of 1CY Blackbird LK25176 retrapped in the garden 22/11/2016

Tail of 1CY Blackbird LK25176 retrapped in the garden 22/11/2016

In recent decades it has become more common for finches to undergo a limited moult of the flight feathers as part of their (partial) post-juvenile moult but this phenomena appears to be a far more recent occurrence in Blackbirds and these two examples are the first I am aware of for the UK. A search of the Internet revealed a short paper about a juvenile Blackbird that was found moulting its primaries and secondaries in Poland in 2004. That appears to be the first account of a juvenile Blackbird replacing its primaries and secondaries and moult aficionados can find that paper here or by searching for the reference below.

As for the cause of the change in the extent of the pj moult in some birds I would put climate change as the number one suspect but as many of the species involved are also frequent visitors to gardens the more extensive and much improved quality of food provided in gardens may also be playing a part. It is certainly an area that is ripe for research and hopefully it will become something that the BTO will take more of a lead on by encouraging ringers to record and report any examples they come across.

References:
Zieliñska M., Zieliñski P., Mokwa T. 2005. Juvenile Blackbird (Turdus merula) moulting primaries and secondaries. Ring 27, 1: 121-123.

The end of another month.

Autumn migration has stuttered along over the last week with quite good numbers moving on some days and very little on others. The last couple of days has seen a modest amount of movement at Billinge and the catches were similarly modest. Yesterday's ringing totals (retraps in brackets) were: Sparrowhawk 1; Goldcrest 19; Blue Tit (1); Redwing 4; Chaffinch 1, Lesser Redpoll 1. Today's totals were: Goldcrest 11; Blue Tit 1; Great Tit (1); Blackcap 1; Fieldfare 1; Redwing 8.

Yesterday's 1cy female Sparrowhawk was the 7th Sparrowhawk to be ringed at the site this month.

Today's female Blackcap was carrying a lot of fat and likely to be a late departing summer visitor rather than a recently arrived winter visitor.

I know I have shown images of these grey headed continental Goldcrests before but this female, caught today, also had a long wing for a female of 56mm. 

Adult female Fieldfare. Not an easy bird to catch when on passage but always worth the effort.

Ringing totals for the month have been excellent with 1,419 birds ringed although that is a little short of the number reached in October 2015. Redwing accounted for just over half the total with 739 ringed and Goldcrest came in second with an equally impressive 377.

Top 5 for the month at Billinge were:
Redwing 739
Goldcrest 377
Song Thrush 59
Lesser Redpoll 36
Chiffchaff 28

Top 5 for the year to date at Billinge are:
Redwing 739
Goldcrest 666
Willow Warbler 367
Chiffchaff 340
Blackcap 219

What will November bring?