Billinge 6th & 7th August: First Tree Pipits

It is that time of year when I expect to get my first Tree Pipits of the autumn and I wasn't disappointed with 1 ringed yesterday and another 3 today. None of them announced their presence by calling before they were caught and I didn't see any of them drop in as I usually do when passing birds are attracted to the audio lures. A total of 3 were seen yesterday but the 3 ringed today were the only ones recorded. Over the last 3 years the first autumn sighting has been between the 1st and 7th of August so yesterday's birds were pretty much bang on time.

Tree Pipit 06/08/17

Other highlights from the 2 sessions were the capture of 4 Garden Warblers and 5 Whitethroats; the latter qualifying a highlight because I only managed to ring 1 Whitethroat in the whole of July. Another 6 juvenile Goldcrest supports my previous comments about the species having a productive breeding season. Goldcrests have a long breeding season and many pairs are probably still churning out more young so it may turn out to be another bumper year.

Garden Warbler 06/08/17

Ringing totals for 05/08/217 were: Goldcrest 3; Blue Tit 18; Great Tit 2; Coal Tit 1; Chiffchaff 3; Willow Warbler 17(4); Blackcap 3; Garden Warbler 3; Whitethroat 2; Wren 1; Blackbird 1; Tree Pipit 1; Chaffinch 2; Bullfinch 1. Total 58 new birds and 4 retraps.

Ringing totals for 06/08/17 were: Goldcrest 3; Blue Tit 3; Chiffchaff 2, Willow Warbler 8 (2); Garden Warbler 1; Whitethroat 3; Wren 1; Song Thrush 2; Robin 1; Tree Pipit 3; Bullfinch (1); Goldfinch 1. Total 28 new birds and 3 retraps.

Billinge 28th to 31st July 2017: More adult Willow Warblers

The weather hasn't been particularly favourable but I managed to get out on the last 4 days of July. I went up to Billinge and set 3 nets in on each occasion although I had to change the net positions on some days to get adequate shelter from the breeze. The 29th provided the best conditions but the sessions on the other days were restricted by light showers and or a strengthening breeze.

I made the effort because I was curious to see how many juvenile and adult Willow Warblers I would catch and if the proportion of juveniles would increase. A total of 100 birds (92 new & 8 retraps) were caught over the four sessions and almost half  (43 new & 4 retraps) were Willow Warblers. Interestingly, the proportion of adult Willow Warblers remained relatively high with 11 out of the 47 being adults, although one had been encountered earlier in the month.

Adult Willow Warbler showing quite an extensive pure white belly.

 The total number of individual Willow Warblers handled in July ended up at 104 and of these 77 were juveniles and 27 were adults which gives a simple ratio 2.85:1. While this is the lowest ratio of juveniles to adults encountered in any July the total number of juveniles handled this July is similar to 2014 & 2015 as can be seen from the table below. 2016 seems to have been an exceptional year for juveniles as a similar pattern was found when I looked at the July totals for Chiffchaff  (2014/42, 2015/45, 2016/73, 2017/40) and Blackcap (2014/35, 2015/42, 2016/65, 2017/41). So the number of juvenile Willow Warblers encountered this July has ended up in what might be considered the 'normal' range for the site.

July Willow Warblers
Year	Juveniles	Adults	Ratio (rounded off)	Visits
2017	77	27	3:1	13
2016	101	6	16:1	13
2015	71	14	5:1	11
2014	81	9	9:1	13

A ratio of just under 3:1 is much closer to the actual productivity of Willow Warblers but that is not what I am used to seeing at this site, hence my interest being sparked by the high number of adults encountered this year. There did seem to be more adults around in the spring so better over-winter survival resulting in a higher breeding population may have played a part, although it appears to be too much of a increase to account for it all. If a much higher breeding population was part or all of the cause then it still suggests productivity is low this year as more pairs would be expected to produce more offspring unless productivity has been negatively affected in some way. There is also the possibility that some of the adults were migrants rather than local birds as some were nearing the end of their moult and many adults will start migrating just before the innermost secondaries are fully grown. Either way I have caught a lot more adults this July than usual and multiple factors may be involved. As I said in my previous post it will be interesting to see how the 2017 CES results and other surveys compare.

 

Adult Willow Warbler showing more extensive yellow across the belly and a relatively pointed tail. This bird didn't shout adult and is the sort of bird that can trip you up if you're not careful and rely too heavily on a particular feature such as the colour of the underparts. Careful examination revealed it was still in active wing moult, but only just, as can be seen in the image below. 

Primary moult was just about complete but the big give away was the inner 2 secondaries that stand out as being that bit shorter than the longest tertial. Examination from underneath showed the inner 3 had some feather sheath at their bases. It is always worth giving those inner secondaries a look as the moult usually finishes with the innermost secondary rather than the outer primaries. 

I don't operate a standardised mist-netting regime so that has to be borne in mind when looking at the figures, ringing effort, however, was reasonably consistent so I still thought the figures were worth sharing. Willow Warblers are declining across the UK with the exception of Scotland and I am lucky to have a site that still has quite a good breeding population and also attracts good numbers of passage migrants (especially for an inland site). In 2016 a total of 367 Willow Warblers were ringed at the site which, like the 2016 July totals, was significantly up on the previous 2 years (2015/256 & 2014/240) so it will be interesting to see what the total looks like at the end of this year.

Highlights amongst the other birds caught included the first Garden Warbler of the autumn. A Whitethroat was also a first for the autumn but an unusually late one at that, I don't catch many Whitethroats at the site but I've usually caught a few juveniles well before the end of the month. Goldcrest on the other hand appear to be having a good year with another 10 bringing the total for July to 19. This compares favourably with the July totals for previous years - 10 in 2016, 8 in 2015 and only 3 in 2014.

Combined ringing totals (retraps in brackets) for 28th to 31st July 2017 were: Goldcrest 10; Blue Tit 3; Great Tit 4; Chiffchaff 4(2); Willow Warbler 43(4); Blackcap 7(1); Garden Warbler 1, Whitethroat 1; Treecreeper 1; Wren 4; Song Thrush 1; Robin 2, Chaffinch 1; Bullfinch 2; Linnet 5; Goldfinch 2 (2); Reed Bunting.

Garden Warbler. A scarce passage migrant at the site with most records coming in late July and early August.

Whitethroat.  A few pairs breed at the site so I usually catch a few juveniles in July but not this year.

Billinge: 6th August 2016

I was joined by a trainee from Merseyside Ringing Group at Billinge this morning and we had 3 nets set up in the top willows just after sunrise. The weather was near perfect for most of the session with no wind to speak of and broken cloud keeping the sun off the nets most of the time. A breeze did pick up towards the end of the morning but the catching rate had already slowed by then and we were thinking about packing up anyway.

The catching rate was fairly steady from the off with Willow Warbler being the most numerous species; the 27 new and single retrap caught being the highest day total of the autumn so far. Most of the juvenile Willow Warblers have completed or very nearly completed their post juvenile moult, as is to be expected by this date, so the capture of a recently fledged youngster in full juvenile plumage was a bit of a surprise.

This recently fledged juvenile Willow Warbler really stood compared to the freshly moulted  and very neat lemon yellow juveniles from earlier broods.

I didn't take any photos of today's juvenile Willow Warblers that had completed their pj moult so here is one from the other day for compaison.

Regular readers of this blog will know my interest in the occurrences of Acros at the site and Sedge Warblers in particular (link here). The capture of yet another adult Sedge Warbler only deepened that interest as it keeps the proportion of adults caught unexpectedly high. However, I am beginning to think the proportion of adults to juveniles recorded could be a true reflection of the population that migrates through the area, although the usual caveats about the small sample size needs to be borne in mind. Perhaps the proportion of adults caught on migration in reedbeds is lower than that in the overall population rather than the numbers at Billinge being too high.

Another adult Sedge Warbler - 3 of the six Sedge Warblers caught this autumn have been adults making it a total of 6 adults out of 16 in the last 3 autumns.

I was full of hope for a good movement of Tree Pipits following yesterdays capture of 3 but it was not to be and we had to settle for just one. While it was the only Tree Pipit recorded at Billinge today others were on the move as 2 were caught at Oxmoor, 17 km to the south and another at Woolston, 18 km south east (info from MRG).

Today's token Tree Pipit

A Garden Warbler, caught towards the end of the session, was the first to be ringed this autumn. They are not common in the area and only occur at the site as a relatively scarce passage migrant (6 were ringed in autumn 2014 and 4 in autumn 2015 with most records coming in August).

1cy Garden Warbler

I suppose I can't finish without mentioning tits again or I should say the lack of them. Once again they were very thin on the ground and none were caught which is exceptional for this time of year. A couple of Blue Tits were seen and both Willow Tit and Coal Tit were heard but that was about it.

Ringing totals (retraps in brackets) were: Goldcrest 1; Chiffchaff 7 (1); Willow Warbler 27 (1); Blackcap 5; Garden Warbler 1; Whitethroat 1; Sedge Warbler 1; Wren 1; Blackbird 1; Robin 1; Tree Pipit 1; Chaffinch 2; Goldfinch 1; Linnet 4; Lesser Redpoll 1. Total 55 new birds and 2 retraps.

Stealth Pipits and 'acredula' Willow Warblers

I wasn't sure if the flat calm and overcast conditions of yesterday morning (17th) would produce much in the way of a Tree Pipit movement over Billinge and initially there was no sign of any passing overhead. The bushes also seemed largely devoid of warblers so I thought I would be in for a quiet morning. However, to my surprise and relief the first net round produced 2 Tree Pipits with a 3rd bird being seen flying out of the net ride. Subsequently I did start to hear the occasional call of a Tree Pipit overhead but many more must have been moving than these calls suggested as another 11 were caught over the following 3 hours. The total of 13 ringed is the best catch so far this autumn and equals highest of last year which was achieved on 14/08/14.

A few of the Tree Pipits have been carrying passengers in the form of ticks like this bird.

I have previously noticed that migrating Tree Pipits don't call as frequently as is often thought and this allows many birds to pass by unnoticed or unidentified. If I hadn't been ringing I would have probably only recorded 7 or so flying over and certainly not the 20+ that must have been involved. Apart from the Tree Pipits there was little else around with only a few warblers being caught, seen or even heard. Although warblers were lacking in both quantity and variety this was offset by quality in the form of 2 Northern 'acredula' type Willow Warblers. These cold grey looking individuals lacked any yellowish-green tones to the upper parts or yellow and yellow wash to the supercilium or underparts as can be seen from the photos below.

This was the more cold and greyer looking of the 2 'acredula' Willow Warblers. The underparts were mainly white but with a very slight pale grey-brown wash to the under-tail coverts, flanks, upper breast and throat. Both 'acredulas' were aged as adults.

The second acredula type was almost identical to the first but with a very slightly browner hue to the upper parts.

Juv Willow Warbler (trochilus) with extensive yellow wash to underparts.

Adult 'trochilus'

Two views of the coldest 'acredula' above a juv 'trochilus'. lower left and adult 'trochilus' lower right. 

Separating the races isn't always straightforward as there are some complications caused by intergrades where their ranges meet. To make matters worse some Willow Warblers that breed in eastern Scotland are said to be greyer than your typical British breeding Willow Warblers. Having said that both of these birds look very good for 'acredula' even if it is safest and the convention to describe them as 'acredula' types in the absence of DNA confirmation. Wherever they have come from I have no doubt that it is a long way north and east of Billinge.

I returned to Billinge this morning in the hope of another good catch of Tree Pipits. Again there didn't appear to be any on the move but like yesterday they must have been in stealth mode as I ringed another 7 despite only faintly hearing one bird flying overhead. There were a few more warblers around compared to yesterday and these included the 4th Garden Warbler to be ringed this autumn. All in all two good days that had elements of both quality and quantity.

Tree Pipit. One of the magnificent 7 from today.

This morning's Garden Warbler - the 4th of the autumn.

Combined ringing totals (retraps in brackets) for 17th & 18th August 2015 were: Tree Pipit 20; Robin 1; Whitethroat 4; Garden Warbler 1; Chiffchaff  5; Willow Warbler 15(1); Goldcrest 3; Long-tailed Tit (2), Coal Tit 1; Blue Tit 1(1); Great Tit 1; Chaffinch 2; Goldfinch 1;  Linnet 1.

TREPI time

August started off fairly quiet with unsettled weather holding up many migrants but a welcome change in the weather to clear conditions overnight and this morning was just what was needed to get passerine migration going again. The sharp drop in temperature overnight resulted in pockets of mist and a heavy dew this morning and it was like walking through a car wash as I made my way through the saturated bushes to the net rides at Billinge.

I soon had three nets up and a couple of Sedge Warblers in the first net round made for a good start and indicated that some new migrants had dropped in. Catching was fairly steady and mainly involved the usual species but an adult Garden Warbler was also notable, being a scarce passage migrant at the site, and only the second to be ringed this autumn. Also of interest was a Willow Warbler that was wearing a ring from elsewhere and is the first of this species to be controlled at the site.

Sedge Warblers don't breed at the site and only a few turn up on passage. It is always interesting to catch migrants like this in bushes on a dry hillside rather than in their usual lowland wetland habitat. 

Adult Garden Warbler

Control Willow Warbler. If you are using rings starting with the letters HLA then the details of its capture today will be coming to you very soon.

Now it was around this time last year that I started to catch Tree Pipits at the site and I soon discovered that it was an exceptional location for the species with a total of 57 ringed and over 133 recorded during autumn 2014. As I hadn't ringed at the site previously I didn't know if it was going to be a regular occurrence or if 2014 was a 'one off' due to exceptional circumstances including the particularly productive breeding season of 2014. I caught the first Tree Pipit of last year on August 4th and today has provided the first really good conditions for the species to be on the move this autumn so it was a delight when 2 turned up pretty much on cue and both were caught. Now I don't want to count my Tree Pipits too early but it certainly is a promising start.

The first Tree Pipit of autumn 2015 and hopefully the first of many

One interesting aspect of the Tree Pipit passage at Billinge last autumn was that it started and peaked earlier than at many of the well watched coastal and inland 'vis mig' sites. It will be interesting to see if the same happens this year.

Ringing totals (retraps/controls in brackets) were: Tree Pipit 2; Sedge Warbler 2; Whitethroat 1; Garden Warbler 1; Blackcap 7 (3); Chiffchaff 5; Willow Warbler 8 (2); Goldcrest 1; Blue Tit 2; Great Tit 2; Treecreeper 1; Chaffinch 7; Goldfinch 2. Total 46 comprised of 41 new birds, 4 retraps and 1 control.

Whilst walking between the nets I noticed that a group of caterpillars had defoliated one of the small willows.

Spot the caterpillars

The culprits were these Buff-tip (moth) caterpillars. 

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)