We're stuck in 2016

Since the end of 2016, the Demography Team has been hard at work loading all the ringing data received from our ringers. Data are still coming in by the 'file load', but here is a sneak peek at a few highlights of 2016.

The big question is always, "how many birds were ringed in 2016?". I don't think we will reach a million birds ringed this year, possibly due to Blue and Great Tit not having a great year. We are currently on 990,808 birds ringed and there is a corresponding 281,880 records of birds already wearing rings (either caught again by ringers or found dead by anyone).

The graph below shows the 20 most ringed species in 2016. Despite them having a poor year, Blue Tit is still by far the most ringed species but perhaps more interestingly, Goldfinch is in second place. BirdTrends records show that Goldfinch numbers have increased substantially in recent years; however it is only the 10th most recaught species.




Top 20 species of birds ringed in 2016. Click to enlarge.

Unlike Willow Warbler, Chiffchaff has been doing very well recently, and as you can see from the graph, was the fourth most ringed bird in 2016. The preliminary results from the CES scheme show that Chiffchaff had the highest adult abundance in the history of the scheme last year. Unfortunately, productivity was significantly down in 2016 and the Nest Record Scheme results show that the mean laying date was eight days later than average. Chiffchaff that had originally been ringed in the Channel Islands, Germany, Spain, France, The Netherlands and Portugal were found in Britain and Ireland in 2016. All, apart from three birds were caught by our BTO ringers, one was found dead and two hit a window (one survived and one didn't).



A young Chiffchaff. Photo taken by Lee Barber

Coming in at number five of the most ringed bird for 2016 was Blackcap. This bird also had a high adult abundance and an even lower productivity than Chiffchaff  in the preliminary CES results. The North Wilts RG ringed an impressive 2,209 Blackcap in 2016, and their ringing session on 11 September, where they caught 257 Blackcap (most of which would have been on autumn passage), will always be remembered by the team on that day.

Male Blackcap. Photo taken by John Dunn.

Some of the more unusual recoveries we received in 2016 include a Blackcap which was found in a 'Horse water bucket', ringed by the West Wilts RG in 2011. We occasionally get birds being hit by vehicles, however I have never heard before of one which was 'trapped inside locked vehicle (entered through partly open window), fresh dead'. We also received a report of the fourth Slovenian ringed Blackcap found by a non-ringer. There are still a few records to be processed of BTO-ringed Blackcap that were found abroad and we look forward to processing those and letting the ringers know if it is one of theirs.

All of the recoveries of fresh dead birds and recaptures of live birds, feed into the longevity records for Britain and Ireland. It will be a little while until the 2016 records are added, but there are a couple of records that look to update the current longevities. The Bisham Barn Owl Group look to have just pipped the current record by a few days, originally set in 2012 (of 15 years 3 months). Click here for more information. The Mediterranean Gull record currently stand at 15 years 3 months as well, and Allan Hale has reported two colour ringed Med Gulls at Great Yarmouth beach, which were ringed just two days apart breaking the current record by over three months.

This post covers just covers the tip of a very big 'data' iceburg, so as we have more time to look into this data, we will undoubtably uncover more exciting information.

Ringing and nest recording; the dream 'info team'

Monitoring nests for the BTO Nest Record Scheme gives us a really good estimate of the number of fledglings produced from the average nest each year, but this is obviously only the first part of the story - for breeding success to have an impact on the future population size, these young birds have to make it through autumn and winter to the following spring. By fitting rings to chicks in the nest and recapturing them as free-flying individuals, volunteers are able to follow their progress over this period. Calculating post-fledging survival rates from these data is actually very challenging as many young will move from the site in which they were raised and settle to breed in areas where there is a lower chance of them being re-encountered. However, those that are observed subsequently provide vital information on dispersal and settlement, key processes by which birds are able to change their ranges over time in response to changing climate and habitat quality.   

Brood of Blue Tit chicks. Photo by Mainwaring

Another big advantage of ringing nestlings is that the exact age of re-encountered individuals is known. Most songbirds have replaced all their juvenile feathers by the end of their first breeding season and, from this point onwards, it is impossible to determine how old they are. As age can have significant impacts on behaviour and breeding success, precise information is very valuable. Another certainty established by ringing chicks is the breeding population from which they originated, allowing researchers to determine which areas are net producers of young birds, and which may be population sinks.

Dave Leech studying Reed Warbler nests. Photo taken by Lee Barber

The totals presented in the Ringing Report show that in 2015 alone, over 167,000 nestlings (termed 'pulli') were ringed across Britain and Ireland. In almost all cases, the chicks ringed in each brood would have belonged to the same species, but there are exceptions, as Ian Wrisdale explains:

On a relatively large site of former gravel pits, I run nest box monitoring scheme, a Constant Effort Site (CES) and conduct autumn/winter ringing between October and December. To avoid the possibility of winter flooding, the ringing activities move from the reedbed of the CES, to an area of scrub/young woodland on the opposite side of the site for the winter. Due to the site being a Site of Special Scientific Interest (SSSI), all of the ringing activities are in accordance with agreements with Natural England. The agreed purpose of the winter ringing is to catch winter thrushes; however, it usually entails catching many tits. Whilst the outcome of the nest boxes is usually recorded as, “Nest Empty”, the winter ringing serves to confirm this outcome, monitor the movement of the birds around the site and allows some comparison of breeding productivity with post-fledgling survival.


The reedbed and wet willow scrub of the CES. Photo by Ian Wrisdale

During the last two seasons I have had two mixed broods of tits sharing the same nest box. In both cases, the brood comprised several Great Tits and a single Blue Tit. It is usual to assume that a single Blue Tit would struggle to survive with such competition but, in both of these cases, there was no sign of a dead Blue Tit in the nest box and the outcome was recorded as, “Nest Empty”, assuming at least a partial success. The Blue Tit in question this year was ringed on the 28 May, at the same time as the seven Great Tits with which it shared the nest. But its survival was not confirmed until it was recaptured during the first of the winter ringing sessions, on the  02 October 2016. Whilst I was pleased and surprised to be able to confirm its survival, it was a small, possibly female, individual (wing 60mm, mass 9.8g), making its successful competition against the Great Tits seem all the more remarkable.

Winter ringing in woodland scrub. Photo by Ian Wrisdale

It is unlikely that I will be able to catch it during the breeding season, unless I can agree, with Natural England, to conduct some summer ringing sessions at the winter site or catch it on the nest, but it would be interesting to see if it goes on to breed successfully, or will it think it's a Great Tit.

Eds - If you are a ringer and regularly ring resident species at a site during the winter, it would be worth considering if you are able to find and record the nests of these species. Even getting in touch with your local nest recorder could be beneficial. As this post demonstrates, the quality of the data can be dramatically increased.

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

RAS: Renewing Acquaintances in Spring

For almost 20 years, the Retrapping Adults for Survival (RAS) scheme has used standardised bird ringing as a tool to monitor adult survival rates of species not frequently caught at Constant Effort Sites. The results are used to generate annual survival estimates which help us to understand more about the contribution changes in the probability of mortality make to population trends recorded by surveys such as the BTO/JNCC/RSPB Breeding Bird Survey (BBS). Birds are generally faithful to breeding sites between years, so RAS methodology aims to re-encounter as high a proportion of returning adults as possible each year; for some species, this task can be made significantly easier by fitting colour-marks, allowing birds to be individually identified without capture. 

The initial uptake for RAS was fantastic, with 75 datasets received in 1998. Since then, the number of projects has risen steadily and in 2015, a tremendous 190 datasets were received. We now have over 200 active projects studying 59 different species. 60% of projects focus on one of the 24 target species, as outlined in the Demographic Targeting Strategy, with a further 11% of projects targeting seabirds (which don’t yet feature in the target species list).

The most frequently studied species are still House Sparrow and Pied Flycatcher, which are the focus of 23 projects each. In third place is Sand Martin, which is studied by 15 RAS ringers, often at artificial banks such as the one at Rutland Water which enable breeding success to be monitored concurrently. Following closely behind is Starling (14 projects), a species that has become increasingly popular in recent years. Prior to 2013, there were only two RAS projects on this red-listed species so the additional data now being produced are very welcome! Not quite making double figures are Dipper and Reed Warbler, which are the species of choice for nine RAS ringers each. Perhaps surprisingly, there are still fewer RAS projects than we might expect on some generally well-ringed species, such as Swallow and Tree Sparrow (six projects each) – we would love to hear from anyone interested in taking up the challenge of a RAS on these species.

This colour-ringed Starling is part of a RAS population in Lancashire. Photo by Peter Alker.

The fruits of RAS ringers’ labours have just been published. The full suite of national RAS results for 2015 is now available and includes a trend for Tawny Owl, which we have been able to produce for the first time following the submission of some valuable historical data. RAS works particularly well for longer-lived species, such as owls and seabirds. A number of ringers with existing, long-term ringing projects have recently registered for RAS, instantly enabling us to produce survival trends for their studies.

A trend for Tawny Owl is available for the first time. Photo by Ruth Walker.

 

RAS survival trends for 12 species (Little Owl, Jackdaw, Sand Martin, Swallow, House Martin, Dipper, Pied Flycatcher, Stonechat, Wheatear, House Sparrow, Linnet and Siskin) are also included in the annually produced BirdTrends report, which provides a range of information about population trends and their potential drivers for over 100 breeding bird species.

We are very grateful to all our fabulous RAS ringers who put so much time and effort into generating this incredibly valuable data. Anybody considering starting a RAS or wondering whether a current project could be suitable for RAS is encouraged to contact the RAS organiser.

Old friends welcome in the new CES season

We recently received the following fascinating account of the first CES visit of the year at Foxglove Covert, Catterick, Yorkshire. The first CES visit period of 2015 is now over and we are already hearing stories of how long-term ringing projects can help us learn more about the productivity, abundance and survival of birds in Britain & Ireland.

Tony Crease writes:

The weather plays a major part in any CES day and the start of the season this year was looking as ominous as ever, so much so that juggling the days of the Bank Holiday became an inevitability. With a CES of ten and a half hours, a day of virtual calm is essential.

Monday provided the window of opportunity and 12 ringers from the Swaledale Group turned out for visit 1 of our 23rd CES season. With trees still without leaves after the recent very cold weather, the usually lush habitat was less than ideal for hiding the nets. Nevertheless, we had an interesting day catching 204 birds of 25 species. The first Blackcap and Garden Warbler of the year were processed as well as 29 Bullfinches, 23 Willow Warblers and many of our routinely resident species. What was entirely unexpected was the age structure of the birds, some of which we find are surprisingly long lived.

An incredible 29 Bullfinches were ringed during the session! Photo: John Harding

Among the more common species we processed was a four year old Chiffchaff, Chaffinches that were four and six years old respectively and six Blue Tits from four to eight years old. Even more fascinating was a pair of Willow Tits; the female, who had a large brood patch, had been ringed on the reserve as a juvenile on 9 August 2007 and had been caught every year since – a total of 37 times in all!

As if that wasn't compensation enough for our very early start, to our complete amazement there then followed R084872, a Marsh Tit which had been ringed as a juvenile in the reserve on 10 July 2004. This bird, we believe, must now hold the British & Irish longevity record for that species*; it has been re-trapped 42 times and has been recorded at Foxglove Covert every year since except 2010 and 2013.

The red-listed Marsh Tit is a regular visitor to Foxglove Covert CE site.
Photo by Tom Wallis

Increasingly, we are finding more results like these with several passerines, including Blackbirds, quite often living five years or more. It is a compelling aspect of our ringing activities and one that has improved so much with the introduction of IPMR. We load the birds as we ring them so information on original ringing data is readily available.

While visiting our Tawny Owl boxes recently we found one bird that had been breeding in the same next box for 16 years. It is an intriguing subject and one that continually delivers surprises. Life is full of the unexpected and our feathered friends in and around Catterick provide many thought-provoking examples.

* Note from the editors - the online longevity records will be updated in June / July to include data from 2014. Until then, we are unable to confirm whether this is a new record for this species. Watch this space...

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.

Half time update for CES

Andrew Harris & Roger Kiddie write:

After a trial year in 2012, we started two dry scrub Constant Effort Sites (CES) last year at the RSPB Northward Hill reserve. In 2012 we did the full 12 visits at one of the sites and seven visits at the other. The results from 2013 showed that adult survival was 37% down, but productivity was 23% up from 2012.

This year we speculated that with the mild winter, adult survival for resident birds would be up but we had no idea what the numbers of returning migrants, mostly Sylvia warblers, would be. We hoped that with a better breeding season than the last two years, productivity would also increase.



We have now completed the first six visits at each site. We have had 244 adults compared with 202 in 2013, showing a 20% increase. Residents have increased from 100 to 112 and migrants from 102 to 132. The species showing the largest increases are Dunnock (20 to 30), Blackcap (26 to 47), Wren (9 to 17), Lesser Whitethroat (10 to 19) and Chiffchaff (15 to 19). Whitethroat are the only species whose numbers have decreased (37 to 34).

Male Blackcap - Adrian Dancy

With the mild spring / early summer, juvenile numbers have been significantly up on last year (115 to 297) showing a near 160% increase. The most obvious increases have been in Blackcap (16 to 87), Wren (1 to 19), Robin (9 to 23), Dunnock (17 to 31), Blackbird (4 to 25), Blue Tit (25 to 48), Great Tit (6 to 19) and Long-tailed Tit (3 to 8). The only species obviously down at this stage of the season is Chiffchaff (19 to 16).

We are aware that our data aren’t representative of all the CES projects nationally, but we are encouraged by what appears to be happening on our site. We have 98 years’ worth of ringing experience between us but until 2012 we had never been involved in CES ringing. We have thoroughly enjoyed the experience and we feel it is good discipline both for us and our trainees and are happy to contribute to one of the BTO’s target ringing projects.

CES Starts in 2013

Today, Thursday 2 May, is the start of the Constant Effort Site (CES) season.  Over the next 10 days hundreds of volunteer ringers across Britain and Ireland will be carrying out the first ringing visit of the CES year.  They will set their nets in exactly the same place and spend the same amount of time catching birds as they did last year.  At the end of the summer, after 12 visits, data will be submitted to the BTO. 

At the end of last year, CES data confirmed that 2012 had been the worst breeding season since CES began in 1983.  The number of birds present at the start of the season was very similar to recent years and adult survival, as indicated by the proportion of birds returning from 2011, was around average.  However, productivity, measured as the ratio of juveniles to adults caught, was significantly lower than average for the majority of species.  All eight migrant warblers covered by CES demonstrated significant declines with Blackcap dropping by 62%. Many resident species didn’t fare much better with Blue and Great Tits dropping by 31 and 34% respectively.

Current CES sites - blue dots were new in 2012.

What will 2013 bring? Most of our ringers are hoping for better weather if nothing else. It was
tough finding enough dry, not too windy, days to do CES last year. More importantly there are two
important questions to answer:

* How did the weather in 2012 affect the adults?  There were anecdotal reports of underweight adults last year as they worked hard to feed their young in difficult conditions.  Some also extended their breeding season in an attempt to successfully produce young, which means they may have ended up migrating or moulting later than normal or in poorer condition.  We suspect that this will affect adult survival, but we need this year’s data to prove it.

* How many birds will return in 2013?  Given that relatively few juveniles were produced in 2012, we might expect numbers to drop this year.  However, it’s possible that the drop in juvenile numbers reduced competition during autumn and winter, resulting in a higher than average proportion surviving to breed in 2013.

CES in 2013 should give us an insight into the answers to these questions.

Allison Kew
CES & RAS Organiser

Late brood

Time is ticking

For many birds, this years nesting season has been hampered with wet weather and low temperatures. As a result, some have been recorded nesting later than they would normally.

On 2 October we received an email from Linda Adam in Devon, who still had a pair of Swallows feeding a brood of chicks! The nest records database shows that of the 45,000 Swallow nest records collected since 1939, only 16 have still had chicks in the nest in October. So this is indeed a very late brood!

Luckily a local ringer Nick Ward was on hand to inspect and ring these chicks, which have now fledged. They will have to gain weight and refine their flying skills quickly before heading south with the other Swallows that are now migrating to South Africa.

Northumbria Swallow roost

Richard Barnes writes:

Northumbria Ringing Group have attempted to catch Swallows at a roost in reedbeds at Birtley Sewage Works in Gateshead since 2006, and up to 2011 have caught almost 5500 birds.

This year, a combination of an easily netted roost site and suitable weather conditions have allowed 9 visits to be made to the roost, resulting in catches of between 205 to 637 birds, giving a total of almost 3500.

In 2010 a Swallow turned up in a mist net on the adjacent CES site bearing a South African ring,  having been ringed in Zambia on 23 Nov 2009. Only 25 Swallows have been caught in Britain or Ireland wearing a South African ring, and on 22 September 2012 we caught another one!

A selection of recoveries of Swallows that were ringed by Northumbria Ringing Group are mapped below (double click to zoom in) but not those recovered by Northumbria Ringing Group and ringed elsewhere.


View Swallow recoveries for Northumbria Ringing Group in a full screen map

Thanks to Linda Adam and Richard Barnes for letting us know and to John Harding for the photo.

Migrant Movement Magic

With migrants starting to move south, we have received reports of a few interesting recoveries.

David Coker writes:
“We managed to slot in our 12th and final visit to our Constant Effort Site at Much Marcle, Herefordshire yesterday morning.  The highlight was arguably a juvenile Redstart; one ‘already ringed’ juvenile Redstart, with a ring number beginning Y190. This seemed familiar to the team members who were ringing, because we used a few of my rings last week after the usual stock ran out; and those rings started Y190. Yes, I had ringed the Redstart, as a chick, on 9 June, in a nestbox at one of my Pied Flycatcher ringing sites SW of Hereford (31 km W of Much Marcle). The trainee who helped me ring the brood was with us again this morning.”

Redstart - Derek Belsey

More news came from Wilf Norman (South Cleveland Ringing Group) who was catching breeding Nightjar in a local forest. Amazingly he caught a male wearing a foreign ring! We have had very few recoveries abroad: BTO birds being found in Algeria (1), France (10), Morocco (2), The Netherlands (1) and Spain (1). Nightjar with foreign rings found in this country are much fewer in number, with the total being … Spain (1).  Now this has been doubled, Spain stand at two. The first Spanish ringed Nightjar was caught only 20 miles from this Nightjar capture, so the North York Moors have 'cornered the market' for Spanish ringed birds.

Nightjar- Derek Belsey

Thanks to David Coker and Wilf Norman for letting us know.

Eggstremely long season

The breeding season starts in earnest in March, you might expect that by the beginning of August, most species would have finished nesting, giving both parents and their offspring time to grow or replace feathers and accumulate fat reserves in preparation for long migratory journeys or harsh winter conditions in the UK. However, volunteers taking part in the Nest Record Scheme are still reporting active nests of many species. It has been a terrible breeding season, with ringers catching very few young birds at Constant Effort Sites and migration hotspots, so these late broods could provide a vital boost to juvenile numbers at the eleventh hour.

After recent flooding destroyed the majority of breeding attempts, we thought that the Reed Warblers at our CES site in Norfolk would give up and move south, but 50 pairs were able lay one more clutch of eggs in a last ditch attempt to make their 9,000km round trip to Africa more worthwhile. The latest chicks will not be leaving the nest until the 26th August.

Yellowhammer

Many nest recorders still have Swallow and House Martin chicks to ring, with young broods reported this week by observers in North Yorkshire, Cumbria and Suffolk and birds sitting on eggs in East Lothian, Dorset and Devon, the latter close to a pair of Spotted Flycatchers with young still in the nest. Some resident species are still nesting too, including an incubating Yellowhammer found in Cambridgeshire on Tuesday, Reed Bunting and Tree Sparrow broods soon to be ringed in Suffolk and Meadow Pipit, Stonechat, Dartford Warbler and Linnet with large chicks this week in Devon.

 

Reed Warbler

Add to this the traditional late nesters such as Woodpigeon, for which the peak of the nesting season occurs in August and September, Collared Dove, Stock Dove, Barn Owl, Moorhen and Coot, and there are still many more nest recording opportunities to be had in 2012! Contact the Nest Records Organiser for more information.

Thanks to Dave Leech for the photos

CES ringers finally get a lie-in

Greg Conway writes:

As the breeding season draws to a close, so the hundreds of dedicated ringers who run the 120 Constant Effort Sites (CES) scattered across Britain and Ireland can start to relax and recuperate after a summer of early morning starts. As they use the same mist nets in the same places each year to catch the birds, the information they collect tells us about changes in numbers of adults and juveniles over time, so abundance, breeding success and survival can all be measured, making this one of the most valuable ringing projects.

Target species include many of our long-distance migrants (e.g. Reed Warbler, Sedge Warbler, Garden Warbler, Whitethroat, Willow Warbler) plus resident scrub species such as Wren, Dunnock, Blackbird and Robin.

The CES scheme started in 1983, so ringers have just completed the 29th season and will soon be focussing their attention on getting all their data to BTO HQ ready for analysis. The results of the most recent CES analysis can be found on the species pages here and the preliminary results from 2011 will be available later in the autumn. These will provide the first indications of abundance and breeding success of birds nesting this summer, helping to assess the potential impact of yet another harsh winter.

Early indications suggest that a number of migrant species have returned in greater than usual numbers. However, despite an early start to the breeding for many species, prolonged periods of cool and wet weather, particularly in the north and west of Britain and Ireland, were associated reduced breeding productivity levels.

A big thank you to everyone whole has help with CES this year and those ringers who have already submitted their data.

Thanks to Dorian Moss for the above picture of Lucy Yates and Kate Risely for the top picture of Nick Moran.

Freezing feathered friends

As the cold weather continues we are finding that birds are still having a tough time trying to cope with the temperature. We are currently on day 6 for England and Wales of cold weather and Scotland has a statutory suspension of wildfowling. The current cold weather situation can be found at our new website.

As we reported previously, birds of prey, especially Barn Owls are being found in poor condition or dead due to the lack of food. Last week we had 39 reports of dead Barn Owls, 3 Buzzard (one of which was 24 years old) and Kestrel, ET51185 which is in care at the moment due to "snow and ice" and is 12 years old. With many water bodies now frozen, wildfowl are finding it particularly difficult and recoveries included 4 Mute Swans and a Grey Heron.


We haven't seen a big increase in reports of small passerines yet, but this could be because their bodies are covered in snow. The reporting rate might increase when things defrost but we'll see. Next summers Breeding Bird Survey and CES will be interesting to analyse for sure.

Note that these are reports and cold weather might not be the exact cause of death.
Thanks to Neil Calbrade for the photo of the ringed Snow Bunting in the snow.

CES completed for another year

We have just had our last CES (Constant Effort Site) session of the season and are looking forward to seeing how this year compares to previous years.

Each year, on our last CES session we organise a 'CES breakfast', where members of the Nunnery Ringing Group and BTO staff who are not ringers get together and celebrate the completion of 12 visits. As an added incentive Susan and Paul Waghorn provide us with a fabulous breakfast after the nets have been taken down.

On this last CES session no less than 50% of the catch were Bullfinches (although this was actually 3 birds). Whitethroat, Reed Warbler and Wren were also caught and a September Swift was seen flying over one of the lakes.

Once all the data has been submitted from all of our CES projects from around the country we will be able to see if it has been a good breeding season or if this was a localised phenomenon (Rye Bay Ringing Group post).

Thanks to Susan Waghorn for the photo.

A good breeding season?

It is a wee bit early for any definitive results relating to this year's breeding season, but we always love to hear about good news stories. Earlier this week we heard from Rye Bay Ringing Group about their captures for July. Even by Rye Bay’s standards, their captures so far this year, for species such as Reed Warbler and Grasshopper Warbler, are quite spectacular (see the graphs below).


Similarly, according to CES ringers Ian Dillon and Alan Bull, the story from Paxton Pits in Cambridgeshire shows that migrants appear to have had a better season than residents. Has last winter’s cold winter had a big effect on this? Future CES results will shed light on this...

CES with a difference

As you would expect, here at the BTO we take part in our own ringing Constant Effort Site (CES). This is a nationally standardised ringing project where we put the same nets in the same place at the same time of year. This means that the numbers of birds caught are comparable between years and fluctuations in the numbers of adults and young can be monitored.

This morning was session number 4 for the Nunnery Ringing Group and the weather was set to give us some good ringing and we were hoping for a large catch. It turned out that the weather was fabulous but as usual we didn't get great numbers of birds, but we did get some unusual species.

As you might have seen from Springwatch last year, we have Cuckoo on the reserve laying their eggs into Reed Warbler nests, but we have never caught one. This is not surprising, as in 2009 for example only 34 Cuckoo were ringed (13 of which were ringed as chicks) over the whole country. This morning though we caught a female that hatched last year (aged on plumage charateristics)!


Out of the 31 birds we caught this was the highlight but we also caught some great birds including Reed Warbler, Blackcap, Garden Warbler, Jay and also some recently fledged Dunnock. It is also nice to know that all these birds were caught on a CES session and the results are even more valuable than normal ringing. For more information on CES check out http://www.bto.org/ringing/ringinfo/ces/index.htm

Thanks to all of the ringers that have helped with our CES sessions over the years, Paul Stancliffe for the photo and to Kate Risely for kindly 'volunteering' to ring the Cuckoo.

Amazing productivity in 2009!

We have just released the preliminary results of the CES (Constant Effort Sites) Scheme for 2009. A quick summary of the results are now online on the CES pages or can be downloaded as a pdf here.



It really was an amazing year, with lots of sites catching their highest ever number of juvenile birds. Of the core 25 species we monitor, 15 had productivity higher than the long-term average which is great news! The only species perhaps not doing so well were Blackbird (lack of access to food during a dry summer?) and Sedge Warbler. Full details are all online now, so do have a look!

Ringing on Springwatch!

Just a very quick post so people can keep an eye out for a piece on ringing which will be on Springwatch either tomorrow (Thursday) or Friday.

We filmed a Constant Effort ringing session at Pensthorpe this morning with Chris Packham and two young helpers, and actually managed to catch a good variety of birds. So tune in to see Sedge Warblers, Chaffinches and maybe even my ugly mug!