Thermal tech lightens the darkest nights

Ben Dolan writes:

In Spring 2017, we were privileged enough to be invited by the BTO to write an article for Issue 5, Spring 2017, LifeCycle magazine on the use of thermal imaging to monitor and ring birds ‘Thermal Birding’. This followed a successful trial, using it to find and ring lapwing pulli, and then using it whilst dazzling, which was a game changer in this area of ringing for us.


Woodcock found by the use of the thermal imagining device. Photo by Ben Dolan

At the time we were using the Pulsar XQ50S; we now use the Pulsar Helion XQ38F with streaming and recording facility.

Since the article was published we have been contacted by many BTO ringers, ringers from Europe and a couple further afield and have had some great feedback that using the device has reduced disturbance, made time more productive, made it easier to carry out bird counts, that surveying wildlife has never been easier and that people have had some first records for their sites using this method.




The view through the thermal imager, catching a Woodcock. Photo by Ben Dolan

Many ringers now own these thermal units and we have had the pleasure of hosting a number of ringers at our sites, as well as visiting theirs, and sharing knowledge which has been a great experience and has helped build new friendships and useful contacts.

The thermal imager is a fantastic tool for bird ringing, finding nests and monitoring nest boxes but it is also great for general wildlife surveys, whether it is hares, badgers, bats, moths and more.

Hedgehog. Photo by Ben Dolan

We look forward to continuing to share our experiences with others and hope they have as much success with the equipment as we have had, with some equally surprising records.

To keep up to date with what we do please follow us on twitter @ringerswm or for our thermal technique guide, visit our website www.westmidlandsringinggroup.co.uk

A big jump in Hawfinch Longevity

With the influx of Hawfinch into southern Britain this winter, Jerry Lewis started one of his feeding sites much earlier than usual (in mid January) hoping to try and catch some of the visitors. Despite a decent sized flock of 40+ birds visiting the feeding site, they were mainly coming down to Hornbeam seed, rather than sunflower seeds. After two months, catching had been very slow (just 16 birds caught, at a rate of one every three hours), but after mid March it started to pick up. The largest catches began from mid-April onwards (as happens most years), averaging a 'finger numbing' two birds per hour. 

Despite problems at two of the feeding sites - sunflower seeds being taken by squirrels/wild boar (leaving few for the birds) and a road closure preventing access to a third site, it was Jerry's most successful year to date. By the time his 'catching season' was over he had caught 202 birds, which included 43 that had been ringed in previous years (plus a small number of same-season recaptures). It is unlikely that many (any) would have been continental birds, as migrants had generally left by early April in previous years.

Photo by Vaughan Thomas  Hawfinch NW31779, ringed 1 May 2008 and re-caught 5 May 2018 (10 years, 4 days later)

Five of his recaptures had originally been ringed in 2010, making them comparable with his current British & Irish longevity record of 8 years 1 month 22 days. One female, caught on 5 May 2018, topped these however, having been ringed on 1 May 2008, 10 years and 4 days earlier; a big increase in longevity. This bird was ringed in the northeast of the Forest of Dean - nr Cinderford, was caught twice in April 2010 - near Tintern in the Wye Valley (20 km SSW), before now moving to near Chepstow (7 km further SSW).

What seems to be surprising is how rarely the 2010-ringed birds had been re-caught (three had been caught once since ringing, the other two hadn't been re-caught at all). Jerry's next challenge is to try and understand why these long-lived birds are not re-caught more often.

How long do Red-throated Divers live for?

Dave Okill of Shetland Ringing Group writes:

On  26 April 2018, Mick Mellor was doing a routine Beached Bird Survey for SOTEAG (Shetland Oil Terminal Environmental Advisory Group), when on Urafith beach, North Mainland, Shetland he found a freshly dead Red-throated Diver (RTD) that had a ring on it. He carefully noted the number and emailed me when he got home. 

Not remembering the number, I started to look back through old, almost fading, files and I found that I had ringed it as a large chick on a small remote lochan not far from Nibon, North Mainland, on 27 July 1985. At well over 32 years old, this individual was an old bird. Looking at the BTO longevity records, the oldest-known RTD was a bird ringed in Hoy, Orkney in July 1986 and last caught at the same location in April 2015, 28 years, 9 months and 7 days later; our bird clearly beats that by some margin! Searching through North American and other longevity lists, it seems that our bird is probably the oldest RTD yet recorded anywhere.

Ringed Dead Red-throated Diver, Urafirth Beach, Shetland. Photo by Mick Mellor.

As well as demonstrating essential information on migrations, movements and dispersal, ringing also gives us the ages of different species; both the average age and the maximum age of the oldest individuals. Longevity records usually creep up slowly, so an increase in the maximum age of RTDs by four years is a notable leap. I suspect that divers are long-lived birds and this record will be well beaten in time.

The ringing site and the finding place are only a few kilometers apart and it is likely that this bird was a male returning in spring to nest in its natal area. Male divers return to breed close to the area where they fledged; females disperse widely before they breed and Mainland-ringed females have been found many kilometers from their fledging loch, up to the North Isles and as far as Orkney. Orkney females have also been found breeding in Shetland.

Red-throated Diver. Photo by Manuel Schultz/BTO.

Over the years our bird will have traveled widely but we only know two points in this bird's life. To help us understand divers better, JNCC are promoting a project to discover what divers are doing, especially on their wintering grounds, now especially important with the proliferation of vast off-shore wind farms which displace wintering and moulting birds from their traditional areas. Birds from Orkney, Shetland, Finland and Iceland will be investigated.  

Editor's note: all recoveries of ringed birds help to further our knowledge, so if you find a bird ring, please report the details at www.ring.ac. 

White bred Sandwich Tern

Ewan Weston from the Grampian Ringing Group writes:

On 19 June, Grampian Ringing Group carried out some colour ringing at the Sandwich Tern colony in the Sands of Forvie NNR, Aberdeenshire. The group has a long running study on the species to gather information on survival, recruitment and movements. While rounding up some of the young for ringing, one eagle eyed trainee spotted a pure white chick amongst the regular coloured chicks. This bird was colour ringed, although we were not hugely hopeful of the prospects for a white bird as it would be more noticeable to predators. The photos of the chick were sent to an expert who suggested the bird was probably not an albino, but has the recessive Ino mutation, which results in very poor oxidation of melanin.

White Sandwich Tern and birds in regular plumage. Photo by John Tymon.

Since ringing, we have had several sightings, initially as this distinctive bird migrated down the east coast of Scotland and then over on the west coast of England at Ainsdale beach in Merseyside where it has spent a few weeks. Several people have sent us photographs of it and it has turned into a truly magnificent tern.

Flying alongside a 'normal' Sandwich Tern. Photo by John Tymon.

From this colour ringing project, over the last few years we have found that once birds leave their breeding sites they spend several months on the UK coast (often north of their breeding sites) before heading south to winter predominantly in Africa. Very few Sandwich Terns return to Europe in their second summer, with most only migrating back to Europe in their third or fourth summer. It will be quite a long wait to see if this bird returns to Scotland in a few years time to breed, but if it does I am sure it will be seen.

As this project highlights, sightings of colour marked birds have helped increase our knowledge of the movements and behaviours of many species, not just Sandwich Terns. So, if you see a colour marked bird (or find a bird fitted with just a metal ring), please report it at www.ring.ac.

Too many males?

Cat Morrison is the lead author on a new paper that, using CES data, found biased sex ratios in small migrant populations, as Cat explains:

For many of us the distinctive songs of our migrant birds are a clear sign of the start of spring, however our recent study indicates that these songs may be masking bigger problems for these species.

Using data collected by ringers we explored the spatial variation in sex ratios of Willow Warblers at CE sites. Our analysis revealed that in 1994, the male-female ratio was around 50:50 however, by 2012 males had started to outnumber females, with the male-female ratio increasing to 60:40. Interestingly, it was also clear that male-bias sites were most common in the south-east of England, where populations have recently declined and Willow Warblers are at relatively low abundances. 

Willow Warbler. Photo by Edmund Fellowes.

We wondered if it was possible that male-biased sex ratios could be due to greater female mortality in the smaller populations, where the greater costs of breeding for females may be exacerbated by poorer resources. However, although male mortality rates were lower than females, this difference was not greater in sites with strongly male-bias sex ratios. Instead, it is likely that the increase in the male-female ratio is the result of female choice, with individuals preferentially recruiting into larger populations, leaving males unpaired in the small populations. This could mean that conservation efforts will be most successful by focusing on sites capable of supporting large populations with more equal sex ratios.

Our work also has implications for how we monitor our bird species, as the higher frequency of unpaired males, singing later into the breeding season can lead to an over estimation of the breeding abundance in male-bias populations.

Further reading:

Morrison, C. A., Robinson, R. A., Clark, J. A. & Gill, J. A. (2016) Causes and consequences of spatial variation in sex ratios in a declining bird species. Journal of Animal Ecology. doi:10.1111/1365-2656.12556

East-West Kingfisher Connection

Here in Thetford we are spoilt by sightings of Kingfishers on our daily strolls into the town centre. As we have blogged before, our breeding birds are residents but the birds that we spot in winter may throw a few surprises.

Such was the case of the sixth recovery of a Kingfisher ringed in Germany that has been reported to us. Whilst it may not be the first or the second from Germany, looking at it in more detail we realised that this was a truly remarkable record. The details were brought to our attention by Dr Martin Flade from DDA who ringed the bird on the 23 July 2015 at Lake Brodowin (Brodowinsee) in the Schorfheide-Chorin Biosphere Reserve in Brandenburg, Northeast Germany, only 12 km from the Polish border.

As can be appreciated from the aerial photographs, kindly supplied by Reiner Krause, the area has a very low human population and encompasses about 240 lakes where Kingfishers typically nest on fallen trees.

German adult male Kingfishers are mostly sedentary, but juveniles and females move. Juveniles leave their nesting area a few days after fledging. One German-born juvenile Kingfisher was recovered on Malta only 22 days after it was ringed as a nestling. Another German bird was recovered as far south as Algeria.

The bird that prompted us to write this post was a juvenile female that was found in Market Harborough, Leicestershire, after having hit a window, and it is remarkable for being the furthest east-west movement recorded by any kingfisher ringed in Germany, as shown in the map below.

Landelin (Martin's son) and Yuma ringing Kingfishers in Lake Brodowin

This is an impressive 1,005 km east-west journey that intrigued us and made us look at the Online Ringing & Nest Recording Report to find out how this movement rates against other east-west Kingfisher movements. As shown in the recoveries map below, there is a yellow dot in Poland of a bird that was ringed on the 06/07/2011 in Rz Drawa, Bogdanka, Drawno, Poland and controlled by ringers on the 25/11/2011 in Orfordness; this bird was also a female. Despite coming from further east, the bird ringed in Poland 'only travelled' 972 km in 81 days, so we can say that the bird ringed by Dr Martin Flade is number one on our east-west Kingfisher connection.

The eastern most yellow dot is the bird ringed in Poland and this post's bird is not showing on this map yet.

Many thanks to Dr Martin Flade for highlighting the relevance of this recovery and for supplying the photographs and very interesting information about German ringed Kingfishers. Martin organised the German BBS from 1989 to 2010. He was also a member of the EBCC (European Bird Census Council).

One Tern Turns the Tabloids

Continuing the seabird theme of last week, today's post is about Lesser Crested Terns (Thalasseus bengalensis).

Lesser Crested Terns are widespread. They breed in subtropical coasts in the Mediterranean, the Red Sea, the Indian Ocean and in the Western Pacific in Australia. Outside the breeding period they range roughly in the same areas.

We occasionally receive reports of these birds, as shown on the map below, mainly from West India, Sri Lanka and one from Sumatra. Not too surprising as all these reports are located within the normal distribution range for this species. 

You may be surprised to learn that BTO rings have been used for a species of bird that normally doesn't occur in Britain & Ireland. But this is not the first time we have written about ringing abroad with BTO rings. Our ringers use our rings abroad in countries where there is not an established bird ringing scheme. One of such countries is Bahrain, a small island country in the Persian Gulf, where some of our ringers monitor breeding terns, including Lesser Crested Terns. Other BTO ringers ringing abroad work in Gambia, South Georgia, Falkland Islands and the Seychelles.

The map below shows where the Lesser Crested Terns ringed in the Bahrain have been recovered and reported. The yellow pin is the ringing site in Bahrain and the red pins are the places where they have been found.

What prompted sharing this story was the media craze that one bird generated in Sri Lanka last week because it was wearing a BTO ring. We received multiple reports from different people, including the finder, a wildlife ranger, an environmental journalist and someone who read the story on the paper. Hopefully as more people are aware of bird ringing, this will increase the reporting of birds and aid their conservation.

To our knowledge, the finding of this bird was on the Sri Lankan News website: Ceylon Today (below). Hiru News had an interesting headline and it featured in a nice article in the Sunday Times (from Sri Lanka).

From Ceylon Today (LITE) on the 29/11/2015



Headline from the Hiru News



Image from Rodrigo Malaka's comprehensive article in the Sunday Times

Owl and raptor mid-season update

That annual Barn Owl breeding success is influenced by peaks and troughs in abundance of field voles, the species' main prey item in many areas, is hardly news to Barn Owl recorders. But after seeing some of the lowest levels of nesting activity in memory in 2013, followed by record productivity in 2014, many might be wondering just when they'll next get an 'average' season. Not in 2015 it seems: anecdotal reports so far suggest Barn Owl productivity has been much lower than expected, though other species seem to have followed on better from last year's bumper season.

Poorer than predicted Barn Owl breeding

Back in February, Barn Owl expert Colin Shawyer predicted that, provided spring conditions remained mild, the exceptional number of 2014 fledglings would mean good recruitment of young breeding birds, but also that though egg-laying could be expected at the usual time in late-April/early-May, a decline in vole numbers from their 2014 peak would result in smaller brood sizes and fewer fledglings this year.

Subsequent early visits to Barn Owl nest boxes revealed much less activity than expected. In late May, Colin visited 25 boxes that had contained 16 active nests in March 2014, only to find just eight with signs of adults present and three clutches of eggs. Non-breeding females were found to be underweight, suggesting that, whether caused by recent wet weather affecting foraging or simply the scarcity of voles, birds were late getting into breeding condition.

By mid-June, reports on the NRS Forum were sounding similar. Alan Ball, Bob Sheppard and Keith Bowden, in Lincolnshire, had checked most of their boxes and found four Barn Owl pairs on eggs or chicks. On the same date in 2014, they had been monitoring 200 nests. Frank Mawby, in Cumbria, Peter Wilkinson, in Cambs, and David Garner, in Cambs, were also reporting low breeding occupancy, and an apparent shortage of prey. Bob Danson, a recorder in Lancashire, commented that food larders had disappeared after the very beginning of the season, in contrast to 2014 when piles of six and seven voles were common.

A single Barn Owl chick at 20-25 days. In 2015 there have been many reports of broods sizes dropping to just one or two chicks. Photo by BTO.

In mid to late July, when Barn Owl chicks are often ready for ringing, there were reports of brood sizes of three and four having reduced to just one—Mike McDowall in East Lothian, David Garner in Cambs and Frank Mawby in Cumbria all ringed single chicks. By the time Bob Danson had ringed his latest brood on 3 August, just eight of the 23 nests he had found so far in his 80 boxes had produced chicks, and his ringing total had reached only 18.

Better Barn Owl news has come in from elsewhere: Nigel Lewis at Salisbury Plain observed a good proportion of boxes with clutches of eggs in May and Judith Smith, in Manchester, has ringed several healthy broods of four and five chicks, including some in new boxes. Geoff Myers, in Lancashire, reported that good numbers of both early and later laying Barn Owl pairs had successfully reared broods and that by 24 June he had ringed a brood of six and several broods of five—very advanced compared to elsewhere.

Tawny Owl, Little Owl and Kestrel fortunes

There have been mixed reports for other box-nesting owl and raptor species that tend to be well-monitored by ringers and nest recorders. Alan Ball, Keith Bowden and Bob Sheppard reported that they had ringed just six Tawny Owl chicks in their boxes in Lincolnshire, compared to 130 in the same boxes in 2014. On the other hand, Bob Danson, in Lancashire, encountered 17 nests in 30 boxes—his second best annual total after last year—from which 26 chicks fledged, including four broods of three. Bob noticed that rats made up a higher proportion of prey in his Tawny Owl boxes, along with baby rabbits.

Several recorders have spoken of Little Owls doing well this year, a species that is obviously less dependent on rodent prey. Alan Ball, Keith Bowden and Bob Sheppard monitored 65 nests and ringed 100 chicks, compared to 80 nests and 188 chicks in 2014. Bob Danson's 70 Little Owl boxes saw occupancy increase to 16 pairs in 2014, from 12 in 2014 and 7 in 2013. He recorded 36 fledged young altogether, including a brood of five and two broods of four.

Two recently fledged Kestrels photographed by Wilf Hockney, who accompanied Steve Baines on several of his Kestrel box rounds this year. 

Kestrel reports have also been positive. Steve Baines monitors 20 boxes in Chelmsford, Essex, and 13 had pairs this year, one of his highest occupancy rates, though he noted that clutch sizes were down relative to 2014: clutches of five and four but no sixes, and that the number of chicks fledged overall (36) was slightly lower than 2014. Bob Danson reported a similarly successful season for Kestrels in Lancashire and noted more bird prey in boxes than usual, including a Swallow. In contrast, Alan Ball, Keith Bowden and Bob Sheppard had monitored only 6 nests by mid-June, compared to 150 at the same time in 2014.

Late season comeback?

Although the breeding season has now finished for Tawny Owl and Little Owl—bar perhaps a few exceptionally late nests—there will still be a proportion of Kestrels tending to chicks, and of course there is the question of whether we will see any Barn Owl second broods or late-season nesting attempts in previously empty boxes. As Dave Leech has pointed out in a recent interview for Radio 4, this might happen if non-breeding females have managed to get into breeding condition, although Colin Shawyer has observed that vole numbers appear to remain very low. Either way, good data on the extent of late and repeat broods is essential for assessing Barn Owl productivity, which is why those late-season box checks are so important...

The BTO Nest Record Scheme is one of the ways in which raptor populations are monitored in Britain & Ireland. These results are complemented by periodic single-species surveys and, in Scotland, by the Scottish Raptor Monitoring Scheme.

Many thanks indeed to: Steve Baines, Alan Ball, Keith Bowden, Bob Danson, Wilf Hockney, Nigel Lewis, Frank Mawby, Mike McDowell, Geoff Myers, Colin Shawyer, Bob Sheppard, Judith Smith, Peter Wilkinson

A Knot eggstravaganza

Delaware Bay, on the east coast of America, is positioned on the West Atlantic Flyway and is the final staging area for many thousands of waders on their migration from their South American wintering grounds to their Arctic breeding grounds. In spring, the Bay is also home to Horseshoe Crabs. These prehistoric-looking creatures spawn on the beaches in their thousands and their tiny eggs are full of protein – just what hungry waders need to replenish their body fat and to provide them with enough energy to complete their journey north.

The Horseshoe Crab eggs that the birds rely on. Photo by Ruth Walker

Unfortunately, for a number of complex reasons, the shorebird populations have diminished in recent years. As a result, in the mid-1990’s, Wash Wader Ringing Group members helped American scientists to establish the Delaware Shorebird Project. The project aims to research and monitor the health of the wader populations on the Delaware side of the Bay in order to better understand the connection between the birds, Delaware Bay and the Horseshoe Crabs. A sister project runs concurrently on the New Jersey side of the Bay. The birds use both sides of the Bay to feed, often swapping shores to avoid inclement weather. The data gathered are helping to identify and protect the resources that are so critical to the success of the wader migration. In part due to the work of the project, the key target species for the project, Red Knot, has recently been officially recognised as ‘threatened’ by the US Fish & Wildlife Service.

Red Knot. Photo by Ruth Walker

Location of Delaware Bay on the Red Knot's spring migration route

A number of BTO ringers, including BTO staff, still travel out to Delaware each May using their holiday time to volunteer alongside other researchers from around the world on this important project. The study aims to catch and fit individually coded colour flags to 350 individuals of each target species each year: Red Knot, Ruddy Turnstone, Sanderling (all of which are colour flagged) and Semi-palmated Sandpiper (though these are not flagged on the Delaware side of the Bay). Samples of Dunlin and Short-billed Dowitcher are also ringed and measured if caught. During their time in the Bay, birds can double their body weight and therefore catching birds throughout the season is vital to ascertain their fitness levels. In order to survive their migration, it is thought that Red Knot need to weigh at least 180g when they depart (having arrived a couple of weeks earlier weighing 110-120g).

The very similar looking Semi-palmated Sandpiper (left) and Sanderling (right). Photo by Ruth Walker

We aim to ensure that approximately 10% of the Red Knot population passing through the Bay are flagged, along with smaller percentages of Ruddy Turnstone, Sanderling and Semi-palmated Sandpipers. Because waders are global travellers, flagging projects are undertaken in a number of different countries. The flag colour indicates the country the bird was flagged in, so birds caught in Delaware have a green flag, but we also see birds with red (Chile), orange (Argentina), blue (Brazil) and white (Arctic) flags . We attempt to catch approximately every three days so that we have weight samples throughout the stopover period, with the rest of the time spent counting the numbers of birds using each of the beaches each day, re-sighting the colour-flagged birds as well as the seemingly endless task of entering and checking all of the data. Re-sighting colour-flagged birds not only gives information on arrival and leaving dates and movements of individual birds within the Bay, but also information on survival and the total number of birds using the Bay.

An American-ringed Ruddy Turnstone foraging. Photo by Ruth Walker 

This year, 362 Red Knot were caught, along with 284 Ruddy Turnstone, 75 Sanderling, 407 Semi-palmated Sandpipers, 472 Dunlin and 78 Short-billed Dowitchers. It was very pleasing to see that of the Red Knot ringed during the final catch of the season, 74% weighed more than 180g, 23% were over 200g with the heaviest bird weighing in at a whopping 228.6g! Thankfully, only 4% weighed less than 150g and would need to remain for longer in the Bay.

As the birds departed the Bay, so did the BTO staff and other volunteers. We look forward to catching up with the birds again next year! 

Buzzard nest with a difference

We were contacted recently by Sam Bayley with the following fascinating story:

Early June marks the time when I check out a few of the many raptor nests that are present in my local area. After discovering three active Buzzard nests and a Kestrel nest I got a small team together including the invaluable help of tree climbers Max Varney and Sam Baker. The first two Buzzard nests and the Kestrel nest were very straightforward with broods of one and two Buzzards and a good brood of five Kestrels, but the third Buzzard nest at South Holmwood was something entirely different!

I had ringed this nest in 2014 when it contained three chicks and it was very typical with lots of evidence of rabbit unsurprisingly being the main food supply. It was very evident even from the base of the tree that this year was different, with a scattering of feathers on the ground below the nest. On reaching the nest Max and Sam found two Buzzard chicks and an unhatched egg surrounded by the remains of various species of bird. Buzzards will take birds, but only occasionally as they aren’t particularly adept at catching them and when they do it is usually limited to chicks or newly fledged birds. The species identifiable were Stock Dove (adult), Jackdaw (adult and nestling), Jay (newly fledged), Moorhen (adult), Great-spotted Woodpecker (adult) and a single Rabbit bone! It looked more like the contents of a Goshawk nest rather than a Buzzard’s, but obviously this pair had become incredibly proficient at catching these birds.

The two Buzzard chicks. Photo by Max Varney

If that wasn’t unusual enough, Max and Sam could hear another bird calling from the nest and eventually realised that it was a Jackdaw chick which was in its own nest within the structure of the Buzzard nest! The adult Jackdaws had created a tunnel into the side of the nest with a chamber at the end, less than 30cm below the cup of the nest! The Jackdaw chick was much younger than its Buzzard counterparts, so I can only assume that the Jackdaws started nesting after the Buzzards were already in residence. 

The entrance to the Jackdaw nest. The two Buzzard chicks
are just visible in the top of the nest. Photo by Max Varney

The Jackdaw chick. Photo by Sam Bayley

Only an end of nesting visit will tell whether they all survive!

2014 proves a good vintage for breeding birds

Throughout the year, ringers and nest recorders have been sending us their impressions of the breeding season. A post in June discussed how the weather in spring made for good nesting whilst one in July considered whether it was nearly time for nesters to hang up their mirrors for the year. On to September and we were reporting on the huge numbers of Blackcaps moving through the country and suggesting that this might be indicative of a good breeding season. Finally, in October, we pulled together stories suggesting that it might be one of the best years yet for Barn Owls. So, do these stories match what the results from the Nest Record Scheme (NRS) and the Constant Effort Sites (CES) scheme tell us? The 2014 preliminary results have just been published and can be found on both the NRS and CES pages of the website.

Barn Owl (photo by Jill Pakenham)

We are very happy to report that the NRS and CES results show that 2014 was indeed a bumper breeding season for both Barn Owl (best ever) and Blackcap, as well as many other species, with the large number of young fledged and high levels of repeat nesting keeping volunteers busy throughout the summer. Reed Warbler, Blackbird and Bullfinch all exhibited the highest levels of productivity since CES began in 1983; interestingly, the two previous best years for Bullfinch were 2011 and 2013.

Less positive were the abundance results which showed that many of our migrants, particularly long-distance visitors, were notable by their absence this year. Only Chiffchaff broke the mould and exhibited a significant increase in abundance. News wasn't great for our resident birds either with only Robin and Wren managing to take advantage of the mild winter and exhibit a significant increase in numbers.

Chiffchaff abundance trend

Those who went to the annual BTO Conference at Swanwick this weekend would have seen the poster showing the regional CES results. While breeding success was generally high across Britain & Ireland, some species displayed regional variation - Sedge Warblers produced more young in the north than in the east or west for example. We would love to hear how your own experiences compared to the results presented so please feel free to leave a comment below. 

CES results poster showing national and regional results (click to enlarge)

We would like to thank all the ringers and nesters who contributed to the CES and NRS schemes this year and to those who provided blog stories in 2014. We hope you enjoyed the season and we look forward to reporting on your 2015 exploits.

Bumper Barn Owl breeding season

Barn Owls are one of our most iconic and recognisable birds. Over the past couple of years this species has struggled due to severe weather events, with last year being particularly difficult as reported here and here. It is estimated by Colin Shawyer of the Barn Owl Conservation Network (BOCN) that only one third of the British Barn Owl population attempted to breed in 2013.

Successful Barn Owl breeding seasons are dependent both on favourable weather conditions and food availability. The primary food item for Barn Owls is the Field Vole which demonstrates cyclical population trends. Reports coming in to us here at the BTO suggest that 2014 is a good vole year and as a result, may turn out to be the best Barn Owl breeding season since 2007. Early estimates from the BOCN suggest that an average of 33% of pairs have had second broods this year, although in some areas, this figure could be as high as 65%. Average brood size (first and second broods) is also high although the recent spell of wet and colder weather may have impacted on fledging success for some broods.

Whilst we have not yet had all of the ringing data for 2014, the totals are already up on last year. For example, in 2013, only 20 Barn Owls were ringed in May and 183 were ringed in June. This year to date, we have received the details of 428 Barn Owls ringed in May and 1,814 ringed in June!

Adult Barn Owl (photograph by Ruth Walker)

The following stories have been sent to us by some of our Barn Owl ringers and nest recorders:

Chris Griffiths of the Montgomeryshire Barn Owl Groups writes:

Our record year was in 2005 when we had 73 pairs producing 249 pulli. Following the two hard winters of 2010 and 2011, then deep snow in March 2013, we slumped last year to 14 breeding pairs producing 49 pulli. This year Montgomeryshire had 37 pairs producing 149 pulli. Interestingly a third of this year’s birds have been recorded at “new sites”, either newly erected boxes, or boxes that have been up a while but have never been used. Many of the “traditional” sites remain empty. For the first time since I have been involved with MBOG, thanks to ringing, I can confirm that we have also had a few second broods this year.

One unusual instance this season was that I found a ringed female bird in a box with four young on 12/6/14. This female was ringed by me in 2013 and counting back she must have started breeding at eight months of age.  On 21/7/14 I found her again 4.4 km away on a second brood of six eggs and one freshly hatched chick. A quick chat with Colin Shawyer revealed she must have left her first brood nine days after I had ringed that clutch. Apparently, this is not unusual but the distance of 4.4 km is! She almost certainly took up with another male, probably on the edge of his “territory” and left the first male to bring up the kids alone (this is something BOCN were beginning to suspect at a number of sites in years where double brooding occurs).  The good news is that the first brood of four and the second brood (which had dwindled to five when I ringed them) all fledged successfully. On returning to the first site at the end of August, we found “superdad” (who was caught and ringed in a nearby box earlier in the season) in the box with another male that I had ringed as a pulli last year 11 km away.

Barn Owl chick (photograph by Ruth Walker)

Alan Ball writes:

Barn Owls have done exceptionally well in Lincolnshire this year. Bob Sheppard and I have monitored nearly 400 nesting attempts from at least 340 pairs and have ringed over 1,200 chicks. We have not rechecked every site, so will have missed many second broods as probably around a third will have attempted to breed again. Now, in mid-October, some of the late second broods are struggling as weather and food availability has an effect, but we are still finding a few healthy broods. Of particular note this year was one fen just south of Bourne, which had six pairs, raising four broods of seven and two of five. It's amazing that one fen of approximately eight square kilometres could furnish enough food for 12 adults and 38 young. Prey encountered in nest-boxes suggests that there has been an abundance of field mice as well as voles this year.

As well as Barn Owls, other species have taken advantage of the abundance of prey and Bob and I have also ringed 449 Kestrel chicks out of 150 pairs monitored, 188 Little Owl chicks from 80 pairs and 120 Tawny Owl chicks. I am now part-way through the daunting task of completing all the Nest Record Cards to record the 2,500 birds of prey handled this year.

Peter Wilkinson sent us this wonderful photograph (taken by Chris Chatfield) of five Barn Owl chicks sitting on their box. 

Geoff & Jean Sheppard, who carry out a RAS project on Barn Owls, write:

Our study area is in the SW corner of Scotland where we monitor about 80 sites, the majority of which have a nest box. Although there was not a large increase in occupied sites, few had single birds and most were successful with notably larger brood sizes. The number of pulli ringed almost doubled but the number is still well below the usual 150+ achieved in the previous decade. For the first time in many years, a pair at one site had two broods, a six and a four. Interestingly, in certain areas, many sites remained unoccupied suggesting that vole numbers had not increased uniformly and this may be due to the fragmented habitat in the study area. This year, in three occupied sites the pulli failed to survive due to death of one or both adults. In one case, this was due to Jackdaws completely blocking the nest box entrance and trapping the female with her chicks at the back. On a lighter note, a pair in a derelict cottage forsook their usual loft space and raised their brood on the corner of an old bunk bed!

Colin Shawyer writes:

Perhaps my most well studied Species Recovery Areas is that in the Peterborough District. This work was initiated in the early 1990s and, as a result of concerted conservation effort, has seen an increase in the breeding population from six breeding pairs in 1992 to 60 pairs today. The 80 artificial nest sites which have been installed here, largely on a 1.5 km grid matrix, have been monitored annually during the last 20 years and the study area now represents the highest density of breeding barn owls in the UK. This year has seen 75 of the potential sites available in the study area, occupied by 60 breeding pairs with about 70% of these double brooding. The average first brood size (close to fledging) this year is slightly greater than four with ringed broods of six, seven and occasionally eight at about 50% of sites. Second broods are still being ringed but as is normally the case, although clutch sizes are generally higher than in firsts, brood depletion is almost always greater with some having gone from seven chicks to fledge one, two and three. The average second brood size at ringing is, nevertheless likely to remain above three. At a few sites, fledging success over both broods has exceeded ten!

Looking out for Twite

As a breeding bird, Twite Linaria flavirostris has undergone a 19% range contraction in Britain since the 1968-72 Breeding Atlas (Balmer et al 2013). The stronghold for breeding Twite in England is the southern Pennines where the population has undergone declines possibly due to reduced availability of seed later in the breeding season (restricting second broods), reduced availability of suitable nesting habitat and moorland fires (RSPB England Twite Recovery Project). 

Steve Christmas and Jamie Dunning started a new project to monitor this population in 2014 and are seeking help looking for colour ring re-sightings. Birds will be on their breeding grounds between April and September but previous monitoring projects and information from ring recoveries suggest that the birds from the Pennines population winter (October to March) on the North Sea coasts between the Wash and the Thames (Wernham et al 2002). In total, there have been six UK based Twite colour ringing projects registered with the European colour-ring birding website although not all of these are still operating. Details of the colour ring combinations used for this project are described by Jamie below.

Jamie Dunning writes:

The South Pennines are the last bastion for resident breeding Twite (Linaria flavirostris) in England and are therefore home to a very important population of these birds (which belong to the endemic ssp. pipilans). Following on from historic research done by Andy Brown, David Sowter, André Raine, Sean Gray et al, Steve Christmas and I have started a colour ringing project on this species this year. As with the previous research, we will monitor movements as well as population dynamics and productivity over the coming years.

Female Twite. Photograph by Edmund Fellowes.

As with all colour ringing projects, publicity is key to getting data back in the form of re-sightings! The Twite we are ringing in the Pennines are being fitted with plain colour rings. We are fitting a single colour ring on the left leg over the standard BTO metal ring and two colour rings on the right leg. The colours used in our project are as follows:

Black (N)

White (W)

Pale Blue (P)

Blue (B)

Green (G)

Orange (O)

Yellow (Y)

Red (R)

Metal (M)

We have ringed approximately 100 birds in 2014 so far. Any birds seen with a combination of the above should be reported to Steve Christmas at: se.christmas@ntlworld.com or myself at: jamiedunning8@googlemail.com. Either of us would be more than happy to give any further information or answer any questions you may have. We would be very grateful if any sightings of birds that are not part of our project could be reported to the appropriate research group (www.cr-birding.org). [As well as replying to you they will inform their ringing scheme of the sighting, adding to the knowledge of this species' movements.] - Eds

For further information on Twite in the South Pennines see the RSPB’s project pages on what they are doing in the way of conserving upland habitat for birds.

Thanks for reading!

Balmer, D.E., Gillings, S., Caffrey, B.J., Swann, R.L., Downie, I.S. & Fuller, R.J. (2013) Bird Atlas 2007-11: the breeding and wintering birds of Britain & Ireland. BTO Books, Thetford.

Wernham, C.V., Toms, M.P., Marchant, J.H., Clark, J.A., Siriwardena, G.M. & Baillie, S.R. (eds) (2002) The Migration Atlas: Movements of the birds of Britain and Ireland. T. & A.D. Poyser, London.

A Chaffinch from Lithuania

Chaffinch by Jill Pakenham

Here at the BTO we know a lot about the common species. We are excellent at monitoring their numbers during the breeding and wintering seasons through several of our schemes. The information gathered by thousand of dedicated volunteers is used to help answer the key conservation questions of our time.
The Chaffinch is undoubtedly one of our commonest species, and as is often the case with such species, (take the Dunnock for example), it is easy to overlook them.

BTO ringers ring more than 30,000 Chaffinches each year. 1,402,733 were ringed during the period 1909-2013, and more than 10,000 have been recovered and reported to us in that period.
Many Chaffinches travel to and from the Continent, and even to the Faroes and Iceland! In the winter we are more likely to encounter Chaffinches that have originally been ringed abroad, as they visit UK & Ireland avoiding the harsh continental cold. In the BTO's recovery database there are 15 Chaffinches that covered a distance greater than 2000km, the furthest recorded distance in our scheme is 2362km, as shown in the map below.

T848360 was ringed a Female in 22-01-2006, coordinates 51°35'N 1°43'W (Wiltshire), later Caught by ringer in 31-07-2006, coordinates 60°41'N 32°57'E (Leningrad) Russia. Greatest distance recorded in the BTO database for a Chaffinch: 2,362km 

In the map of recoveries below you can see that the movements of Chaffinches to other countries are most likely to be between the UK and the Scandinavian countries, Belgium, The Netherlands and Germany, with a few going further east to Latvia, Russia and Lithuania.

Chaffinch: Ringed in Britain & Ireland, Found Here; Ringed Here, Found in Britain & Ireland

This week, we received a recovery of a Chaffinch ringed in Lithuania. This bird was ringed at Ventes Ragas on 30/09/2012 and killed by a cat in Gurteen, Galway on 25/11/2013. It travelled a respectable distance of 1926km and is the first ever Chaffinch ringed in Lithuania reported to the BTO. Before this bird, we have only one other record of a Chaffinch travelling between UK and Lithuania; that was ringed in Kilnsea, England, and later found in the same ringing station in Ventes Ragas, Lithuania.

Vast information on ringing and recoveries of all species in the UK & Ireland and associated maps can be found in the Online Ringing Reports - if you haven't visited yet, take a look!

We have also talked about Chaffinches here.

Icky went to Belgium

I hope you were able to celebrate World Migratory Bird Day over the weekend and that your field notebooks are now full of goodies to talk about. I thought I should tell you about a little migration story I found out about a few weeks ago.

Since the beginning of the Ringing Scheme a grand total of 1,091 Icterine Warblers have been ringed in the UK & Ireland. To my surprise only 5 of them have ever been recovered and reported to us, which meant that the report of an Icterine warbler with a BTO ring from Brussels was good enough to please the ringer (and the recoveries officer!)

Icterine warblers are normally passage visitors, with only a few confirmed breeding records in the UK. It is not surprising that practically all records of this species species are from the east coast. The graph below from sightings reported through BirdTrack shows that there is a small number of reports at the end of May-beginning of June during the spring migration, however, the majority of birds are reported in the fall migration from mid August.

On the 8th of June 2012 an Icterine Warbler (age 4) was trapped and ringed in the Isle of May. Presumably, this bird arrived at its breeding grounds somewhere in Continental Europe or Scandinavia, attempted breeding, succeed or failed, returned to its wintering grounds in Tropical and Southern Africa, and then returned to Europe in summer 2013 to breed again. And it was then, in July 2013, that this bird was re-trapped in a ringing session in Koksidje, Belgium.

Although according to the recovery report that we sent to both the ringers in the UK and Belgium says this bird travelled 661 km, obviously a few thousands kilometres more have been covered by this bird in reality!
Of the 5 recoveries of Icterine warblers in the BTO's ringing database, this is only the second found abroad, the other one having been found in France.



To find out more about the Isle of May please visit their web here.

Nunnery nesting in 2014: off the mark!

We’re fast approaching the time of year where I grab my trusty nesting stick, Carl Barimore reaches for his mirror on a pole and Mike Toms straps on his endoscope as we head down to The Nunnery reserve to start looking for nests to monitor. We generally begin searching in late February, when the Long-tailed Tits begin to pair up and hang suspiciously around likely nesting sites (here typically gorse or bramble) and the first grebes, Mute Swan and Coot start gathering material. However, we’re always on the lookout for opportunities before that, and one was provided on the 15^th January by our colleague, Neil Calbrade, who spotted a sitting Collared Dove in the Nunnery garden, the nest wedged between the branches of a  yew about 3m off the ground. This morning was the first chance I had to check it and the bird flew on my approach to reveal a single white egg; the ‘standard’ clutch size is two, but clutch sizes of early attempts made by multi-brooded species are often smaller (single-brooded species show the opposite pattern).

The typical view of a Collared Dove nest is the underside of a twiggy platform, several metres off the ground in a tree or shrub. It is almost always possible to see the adult sitting from the ground. Photo by  B Besley

It may be tempting to blame the unseasonably warm weather for this apparently early attempt, but Collared Dove is actually the only species in the BTO Nest Record Scheme (NRS) dataset that has been recorded as breeding in every month of the year (Fig 1), although if as many recorders focused on Mallard, it may well reveal the same pattern.

Number of NRS Collared Dove records for which an accurate laying date can be calculated by month in which first egg was laid

That said, fewer than 30 January attempts are logged in the NRS database, dating back to the mid-1960s, and this is the fifth nesting Collared Dove nest we’ve been informed of in the past fortnight (the third in Thetford alone), which suggests they may have made an early start.  It is impossible to compare years without first collecting the data, however; analyses are orders of magnitude more powerful than anecdote when it comes to influencing Government policy on climate change, so it is vital your records are submitted to a national nest-recording scheme.

So, why not make 2014 the year that you register with the Nest Record Scheme and get involved in nest recording – it’s great fun, you’ll learn a huge amount about the birds around you and, vitally, it provides information to support conservation efforts that can’t be gathered any other way.

Information about any species, no matter how common, in any habitat, be it your garden or a remote island, are of value as long as you can see inside to count the eggs and chicks. Looking in nests is perfectly legal as long as you don’t handle the contents, although a licence is need to monitor nests of Schedule 1 species and be sure to follow the NRS Code of Conduct

We’ll be monitoring the progress of our Collared Dove and about 400 other nests across The Nunnery over the course of this season, from Wrens to Mute Swans; we’ll keep you posted on our progress and we look forward to hearing about yours.

Dave Leech, Head of the Nest Record Scheme

http://www.bto.org/sites/default/files/u15/downloads/publications/legislation_and_good_practice.pdf