Siberian surprise

At the woodland  CES site at Llandilo this morning a single net was opened, mainly as a form of distraction to alleviate the monotony of sitting at the computer writing reports. There wasn't much around really, with most of the summer migrants having left and even the resident birds seemed to be elsewhere, so it was a very pleasant surprise to pull a yellow-browed warbler out of the net! With up to 74 of these recorded in a day on Fair Isle recently, it is perhaps not surprising that they are starting to turn up in the south west, but it is nevertheless a nice bird to get on your local patch.

Among the 20 or so other birds caught there was a control great spotted woodpecker, LH96113 (already entered into IPMR) so hopefully will find out where that came from soon.

Identity crisis

As in recent years, the mid summer period has been dominated by a nightjar population study at Brechfa Forest with a view to better understanding any potential effects of wind development. This is in association with Tony Cross who initially worked at the Brechfa site for many years before taking on two other intensive projects at sites in South and Mid Wales see http://midwalesringers.blogspot.co.uk/.

Whilst trying to catch nightjars for ringing and radio tagging, it is very common to catch a few swallows going to roost in the sitka stands during late July and August, though we have never caught a house martin. So whilst extracting a white-rumped hirundine from a mistnet last night I thought -  oooh a new species of by-catch for Brechfa! But as it changed angle it began to look more swallow-like. After a brief bit of even more excitement, I thought "what about a juvenile red-rumped swallow?!" but this idea was quickly quashed by the lack of any collar, so hybrid house martin x swallow it had to be,

The back end looked very much like a house martin with a deeply forked tail

The front end was more like a swallow though the amount of red above the bill was much reduced and the gorget was very pale

The feet were much paler than on a swallow with the faintest trace of the white feathering found on a house martin

Back to what I should have been doing, the nightjars are nearing the end of their breeding season, which has been a challenging one for them in terms of weather. There have been prolonged unseasonal cold snaps in the first half of June and late July and some very low night time temperatures e.g. 4.5degC last week. The wind has also been an issue with very few nights suitable for netting making capturing adults for radio tracking difficult. Nevertheless, the study has gone very well and productivity looks set to be very similar to the last two years largely due to lower levels of nest predation than usual compensating for any losses due to bad weather. One of the most satisfying moments of the study is when at the final nest visit, the fledged young are sat tucked up with an adult.

Adult female and two juvenile nightjars

Interesting Recovery

We have just received details of a Sedge Warbler which we caught at Mullock on 20th July 2014 - presumably on passage at that time.
It was ringed at the Reserve N'Diael, Senegal on 5th January 2014 so was wintering there and returned to the UK for the breeding season.  We do not often come across birds ringed in their wintering quarters so this is a nice record.

Stormie Ringing

The Teifi Ringing Group came and helped out on Wednesday with a successful Storm Petrel Ringing session and they have already posted some details. 

One of the things we were looking at is the wear and moult patterns on the wings of the birds and of the 101 new birds caught one with very worn wing feathers throughout and with dark chocolate brown wings generally looked like a good candidate for a 2014 returning juvenile.  Another bird looked like it had replaced all its secondaries but nothing else and many showed wear and fading on the greater coverts and tertials - which is to be expected if they are almost a year old and are fundamentally protecting the other wing feathers when the bird is at rest. 

One of the controls was a French ringed bird,  the first time we have caught a bird with a French ring, and the two other controls were ringed on Skokholm on 26th and 30th July 2014 - so they are back in local waters.

New CES

A new constant effort site (CES) was started in woods at Llandilo in May. So far, five visits have been made and everything looks good in terms of numbers of birds caught for carrying on long-term. Like many woodland CES sites, the catches are fairly modest in terms of numbers, especially if you compare it to scrub/reedbed habitats.  So far 22 species have been caught and there has been an average of 32 birds per visit though catches should increase as juvenile birds become more mobile.

Five nets are set in willow/alder carr and sessile oak woodland. Nets only catch well where the canopy is <20ft

Although the catches are modest in terms of numbers, they have been perfect for training sessions

Blackcap is the most numerous species caught, 28 individuals so far

Newly fledged young blackcaps (right) are have noticably duller brown caps than adult females (left). The first Juvs are only just starting to be caught, slightly later than most years

The kestrel colour-ringing is continuing and so far 18 chicks have been ringed from four nests

Young kestrels usually clamour to be first in line to get their colour-bling, but these were well-mannered and formed an orderly queue 

A brood of three yellowhammers was a bonus find, a scarce bird nowadays.

47 and still counting

Since the last post, several visits have been made to the wheatear RAS site to try and bling up an acceptable minimum sample size of  50 individuals and this year success looks very likely; thanks to the dedicated efforts of Mike and Theresa we only now need to catch another three individuals to add to the total of 16 re-sightings and 31 new birds caught so far. Mind you, to reach this total we have had to accept "immigrants" - Teifi RG immigrants at that! The last individual to be added to the tally was a female wheatear originally ringed as a juvenile on 4th July 2014 at Carn Ingli by Karen (Teifi RG). It is only 8km as the crow flies from Carn Ingli and the date and age of the bird suggests that it was presumably born very locally to Carn Ingli before settling to breed within a few km here at Carn Breseb (v
ia Africa). This is the only recorded movement away from the site despite ringing 312 wheatears since 2008. It is also very appropriate that the bird was ringed by Karen who often makes the long foot-slog up the Preselis to help with the project.  Luckily the politics of the group welcomes migrants!

Karen's wheatear with added colours

The 2015 wheatear season is running much later that last year and is more on a par with 2013, an exceptionally cold spring with delayed breeding and small broods. Following a very sunny April, May has been relatively cold and quite windy so perhaps this has caused females to delay egg-laying, or even abandon and start again. So far no fledglings have been seen. Another potential cause of nest failure is predation. Wheatear nests are completely safe from corvids and at this site from foxes too - who often try to dig them out unsuccessfully, but it was clear from the response of three male wheatears that they absolutely panic in the presence of weasels. During one of the visits a weasel was seen systematically searching any crevice or hole it could find and up to three male wheatears were in attendance, all hovering within a foot or two and giving off a very agitated rattle-like alarm call. The weasel didn't seem to find anything and it later became clear that very close by a female wheatear must have been incubating a clutch that escaped predation.

A weasel on the prowl - probably looking for voles but three male wheatears were in a panic

Another unusual record this spring was a wheatear caught on 29th May in full moult - this normally starts at the end of |June or mid-July following breeding, but this bird must have started by 20th May. Whether this was caused by the cold weather combined with a failed early breeding attempt is not clear, but it is extremely unusual for an adult of any migrant passerine to be in moult this early.

Male wheatear in full moult on 29th May

Adult male

Wheatear RAS is on

Most adult wheatears that make it back return to the exact territory that they bred in during the previous season

This is the third season of the wheatear adult survival study (RAS) at Mynydd Preseli and it is very much hoped to get the sample of colour-ringed adults up to 50 this year. This is something that was the aim in 2013 and 2014 but annual totals of only 26 and 30 respectively were achieved. Rather than admit failure though, this underachievement has been classified as an essential learning-through-experience part of the project. The open habitat means mistnets are unsuitable so the birds are caught for colour-ringing in spring traps baited with mealworms.

A few things learnt:

Although some wheatears are caught readily, they very quickly become trap shy and if they witness another individual being caught they become highly suspicious of the traps and become very difficult to catch. During the egg-laying and incubation period the males usually mate-guard the females by following them about whenever they are off the nest, so it is difficult to find a time when females are on their own. Whilst females are on the nest, the males tend to sing and generally loaf around, so they don't spend much time feeding. They are only attracted to the bait when they need it, so on nice warm sunny days when they are often well fed, they ignore it.

If the nest is full of hungry chicks then both adults are much more likely to be tempted by the bait and this is when most birds are caught. However in 2013 the very cold weather in May meant that there were lots of nest failures, and those that were successful had small broods (e.g. brood sizes of 1 and 2 were frequent instead of the usual 4 to 7). The weather subsequently turned warm and dry and this left many pairs not that desperate for the bait.

Once the young fledge, the adults seem to switch from feeding them soft prey to adult insects and aren't fussed about eating mealworms, so they have to be caught before they fledge young. In 2014 the season was surprisingly early and about 50% of pairs had fledged young by the time of the first visit on 24th May.

The secret of catching all the adults lies in timing the catching effort to coincide with feeding nestlings, so regular reccy visits from late April onward are essential to keep a finger on the pulse of what each pair is up to.

Some of the colours fade whilst the birds are are in their sunny African wintering grounds. Red, in particular, fades to a sort of pinky-orange within a year making it almost impossible to tell from orange with certainty. Light blue seems to get much paler and can appear white. Luckily all the ambiguous combinations were not applied to the same sex, so all birds are still uniquely marked.

red over grey in May 2013

The same bird a year later

In 2014, 12 out of the 26 marked in 2013 returned (46%), and so far in 2015, 12 out of 30 have been confirmed, though not all territories have been checked so the figure will almost certainly rise.

Dipper boxes 100% occupied

-Well almost! This winter we extended our dipper box scheme on the Eastern Cleddau catchment from 9 to 20 and we have just completed the first round of nest checks. Amazingly there were signs of occupancy in all bar 1 box, but even this site had a dipper nest on an existing ledge under the bridge so we are still counting it. Not all were used by dippers, three had grey wagtail nests and another had an unlined wren's nest - which resembled a miniature dipper's. Only three of the bridges where the boxes were placed previously had any potential crevices or ledges for dippers to nest, which presumably explains the remarkably high take up.

A total of 17 dipper nestlings were ringed from four broods that were ready including a brood of five. All the complete clutches were of either four or five eggs.

A healthy brood of four dippers at perfect ringing age

At one of the sites two clutches each of four dipper eggs were found in either side of a single box. Neither clutch felt warm, so it wasn't clear what was going on. Maybe the next visit will provide the answer?

You don't need to bother taking a ladder if you take Paul

Grey wagtail sat tight on a clutch of five eggs

A cliff hanging diversion during the day produced these raven chicks which were off the weighing scales - over 1Kg each.

All in all, a very productive and entertaining day.

Paul, Karen, Mike, Theresa and Paddy.

Last woodcock of the winter?

While out last night on what will probably turn out to be the final lamping session of this winter, three woodcock were ringed out of five seen, together with a redwing and a meadow pipit. Numbers of woodcock in February were noticeably lower than in the same month in 2013 which had followed a snowy January, but catching conditions have been better so a personal total of 84 captures is not too dissimilar to the average of 99 over 5 previous winters. Other species have also been encountered in lower numbers than usual including redwing with just 4 ringed. Perhaps they prefer to roost in more sheltered sites than open fields during wet and windy conditions, or maybe there are fewer birds this far west than usual. The total for snipe (18) is the highest ever though this is more down to the cloudy, windy nights making them (slightly) easier to catch.

Poised and ready to fly to Russia, maybe the final woodcock to be ringed this winter

Hardly any redwings have been seen in the Pembs fields this winter and this was only the 4th to be ringed

 

Waders and owls

Eight members of the group made another trip to our main wader site at the weekend during a brief spell of calm conditions which resulted in a catch of 47 individuals. Not only is this the highest so far at this site but it was also the bulkiest with 21 curlews, 13 oystercatchers and 11 redshank, all of which are target species for our new colour-ringing project. Unfortunately this project is not yet underway as it is still awaiting approval to use the intended combinations, so no birds were fitted with rings, but at least it gives confidence that sufficient numbers of individuals will be caught to establish a viable project.

Adult curlew

Most of us are unfamiliar with seeing curlew in the hand at this time of year so there was a good deal of deliberation over how to correctly age them: the above bird was aged as adult based on the even age of the feathers, though some birds appeared ambiguous.

Three curlews and a teal being processed 

The adult oystercatchers (age code  = 10, or 4 years +) were startlingly bright

This adult male barn owl was first ringed by John as a nestling 12km away in 2013. It was quite a surprise to find it in a wader net.

This tawny owl was caught last week visiting a garden on the Pembs/Carms border

Waders and wrens

Pembrokeshire is an important county for wintering waders with a combination of coastal and estuarine tidal habitats together with abundant damp pasture inland. Its mild climate means that it sometimes attracts nationally important numbers of waders, especially when the weather is freezing to the east.  Many of the species involved are well monitored by volunteers participating in the BTO's WeBS scheme, but in order to understand the reasons behind any population changes it is vital to mark individuals to help measure longevity, adult/juv survival, site fidelity and many other useful things. 

The plan this year is to considerably expand the wader ringing effort by starting colour-ringing schemes for four common species that are known to be declining - oystercatcher, curlew, whimbrel and redshank. A colour-ringing scheme for whimbrel has already been initiated by Tony Cross and the Mid-Wales team  with good numbers being caught so far and some interesting movements recorded and hopefully by adding some ringing data from Pembs a lot more will be discovered about this spring migrant.

During a recent evening of netting waders with Paul, Mike and Theresa, 36 birds were caught, 32 of which were oystercatchers, including 4 retraps ringed at the same site during the past two years and 4 BTO controls from elsewhere. In addition, 3 redshank and a greenshank were ringed.

Oystercatchers are one of the few species for which the age code of "10" can be used, though this is only a "7" 

The difference in leg colour between adult (right) and 1stW redshank is still obvious at this time of year

  

greenshank are always a joy to see in the hand, this is the second so far this year

This kingfisher added a bit of sparkle at Paul's wader ringing site on the estuary

On a completely different note, it is not very often that ringing wrens would be worthy of a mention on a blog but during the past few nights there has been a steady trickle of them into my house! They must be getting in under the eaves and then deciding that it would be even warmer if they came and sat by the log burner, so by about 9o'clock  there might be 2 or 3 flitting about. They are quite difficult to catch by hand, seemingly able to vanish just as you are about to touch them. Altogether 15 individuals have so far been involved, with 8 of them being adult and probably male.

The barring on the wing of an adult wren is much finer than on 1stW

Monitoring winter woodcock and snipe

Positions of woodcock encountered during nocturnal ringing activities and plotted using hand-held gps

Over the past few years counts of woodcock and snipe have been made whilst out in the fields trying to catch and ring these species, and sometimes their positions plotted as shown above. On some (most!) nights the birds are very jumpy and many of the birds seen are not possible to get close to, so it can be consoling to redefine the purpose of the visit to making counts rather than ringing the birds!. Nevertheless, over 800 woodcock have now been ringed within Pembrokeshire since Dec 2008 (this total includes Teifi RG's birds from the north of the county) and these have generated some interesting recoveries, with at least 10 from abroad, mostly Russia, and perhaps 30 or more local movements. It is hoped to summarise these at some point in near future.

It seemed this year that there were fewer woodcock and snipe being encountered than usual and so all the counts made over the last few winters were compared with those made so far this winter and then divided by the area of fields covered to give a density/Ha. After removing biases that appear as a result of a tendency to choose visiting the most productive fields, the figures are;

 

Data collected from 80 different fields with a total of 400 visits are used to produce the figures above and it appears that counting birds per field at night, if done systematically on a wide enough scale, is a simple way of monitoring change of wintering numbers in these species which both have declining breeding populations in Britain and Ireland, and are not covered well by existing schemes such as WeBS.

The variations in numbers are not necessarily due to population decline as they may simply reflect distribution changes that are weather related, and the mild autumn may mean many birds have not traveled this far west and other areas may have more birds than usual. A cold snap may change that.

Plenty of other research can be done off the back of these counts, especially if bird positions are plotted with gps which is also a simple and accurate way of recording counts. It seems that field size, slope and use, are all important factors affecting density of feeding birds.