23 December 2016

It's not just the bells ringing at Christmas!

With only a few days to go until Christmas Day, many people will be doing some last minute shopping and travelling to see family. There will be some however that try and make the most of the national holiday by going ringing. Partridges in pear trees are unlikely to be the primary target, but many garden birds are likely to be gathering for their own Christmas dinners.

Total number of birds ringed on Christmas Day each year

The total number of birds ringed on Christmas Day is usually around 400-700 birds, so are there any little gems in the recoveries in the BTO ringing scheme database? Of course there are!

In 2015, 59 different ringing groups or individual ringers encountered a total of 659 birds. Eight birds ringed on Christmas day have subsequently been found or recaptured on the same or subsequent Christmas days. For example, a juvenile male Blackbird ringed at Wolverton, near Stratford, Warwickshire on 25 Dec 2013 was caught in the same place on 25 Dec 2014. An adult Blue Tit from Thorpe Street, Hinderclay, Suffolk ringed on 25 Dec 2013, was caught exactly two years later at the same location by the Little Ouse RG. 

A male Blackbird, colour ringed in the same Holt garden

A juvenile female Blackbird, ringed by BTO's own Dave Leech on 25 Dec 2007 was seen two years later in the same garden in Holt, Norfolk. This bird is part of a more intensive colour ringing project on Blackbirds in Holt. Dave’s mum, Barbara, amassed 108 sightings of this bird in total, helping us understand the way in which these birds use gardens throughout the year.

What will Christmas day 2016 hold? We will know soon enough, but until then, we wish you a very happy Christmas and New Year! A special thanks to our wonderful ringers, supporters and reporters for their valuable help during 2016, helping us to shed ever more light on the wonderful research field of avian demography.

24 November 2016

Migratory Moorhen?

BTO volunteer, Lawrence Potter writes:

"Whilst doing our monthly BTO WeBS count at Woodbridge, Suffolk, I noticed a moorhen feeding on the river alongside a pontoon as it looked to have a coloured ring. I asked my colleague (Robert Johnson) to have a look with his telescope and after about 10 mins of observation we got details on the ring; AE32. We were both intrigued with who was colour ringing Moorhen, wondering where it had been ringed, so we submitted it and the results were amazing!

The ringer, Carsten Lome writes:

We started colour ringing Moorhen and Coot in Norway in spring 2013. So far 104 moorhens have been ringed, 54 of them ringed this year. Nearly all have been caught in three cities; Oslo, Bergen and Stavanger. All of the birds in Oslo migrate, so are ringed during the summer only. The majority of the Moorhen in the other two locations are mostly caught during the winter. There have been a few movements between Bergen and Oslo, although how they tackle the mountains in between is unknown. We've also had one bird ringed in Bergen and found in Stockholm.

AE32 was ringed as a breeding bird in Oslo in July this year. Interestingly its partner was ringed last winter in the city centre of Bergen (300 km from Oslo)! Unfortuately they have exactly the same wing length, so sexing them is currently not possible. This pair had three young in their first brood and only two in the second brood, which had not fledged by the last time we visited this pond on 11 October but hopefully did so soon after.

For a species that is thought to be fairly resident, we have had three BTO ringed Moorhen found in Norway but this was the first Norway ringed Moorhen to be reported in Britain or Ireland. This is a distance of 1042 km in 120 days.

Colour of location: Purple - Originally ringed in Britain & Ireland; Orange - Found in Britain & Ireland

For more information on the WeBS counts for Moorhen click here.

There are colour ringing projects all over the country that need your sightings. In Suffolk alone there are Redshank, Black-tailed Godwit, House Sparrow, Herring and Lesser Black-backed Gull, Kittiwake, Peregrine and Mute Swan to name a few. A list of projects can be viewed at European Colour-ring Birding.

16 November 2016

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.

04 November 2016

Fire with red and yellow

It has been an exciting time in the Demography team over the past month, with data and news arriving in earnest. In terms of bird migration, the winds were coming from the east, bringing rare birds with them to our shores, as described in the BTO Bird Migration Blog.

Yellow-browed Warbler featured very highly last month, with another bumper year, see BirdTrack reporting rate graph below. At the beginning of October, Fair Isle Bird Observatory counted 72 and Cape Clear Bird Observatory managed to ring its 60th Yellow-brow of the autumn. West Cornwall Ringing Group have also been doing very well for this species with 56 ringed so far this autumn.

The Online Ringing and Nest Recording Report shows recoveries for Yellow-browed Warbler are few and far between, with exchanges only occurring between Britain and Ireland and the Channel Islands, Norway and the Netherlands. This year however, we have heard that one was caught at Brownstown Head, Ireland wearing a Russian ring! Hopefully we will get all the data soon.

Yellow-browed Warbler, taken by Lee Barber

Another autumn visitor is the Firecrest and we have just received the ringing details of a Firecrest recaptured a few years ago by the Teifi Ringing Group wearing a Belgium ring. This bird had travelled 566 km in two months and 10 days.

Whilst migration of small passerines is starting to reduce, thoughts now move to the influx of winter birds such as thrushes and Waxwings. Redwing in particular have been arriving in large numbers, and some ringers are getting close to 1,000 birds ringed this autumn. We will have to wait and see if our 2016 ringing total for Redwing beats the 11,743 ringed in 2015, but it is looking good so far.

28 October 2016

DemOn in DM out

Dorian Moss is retiring from the BTO as Ringing Database Officer today.

It is best to smile when you are at work!

He joined the team in May 2008, particularly so as to draw up the specifications for the new ringing database, and was one of the team bringing this to fruition in 2014. He has been one of the five staff managing ringing data and recoveries for the past 8 years. From 2008 to 2014 he had the main responsibility for final checks on recoveries and moving them to the permanent database and sending them out to ringers and finders. Then in June 2014 the new database went live, and Dorian started to concentrate on managing the vast resource of ringing data input by our volunteer John Bonell.

Dorian in his favourite habitat, the ringing schedules store at The Nunnery

Since we have been using the new database, Dorian has taken a special interest in checking out new ringing sites, making sure that the grid references and coordinates are correct by checking on maps and Google Earth. Ringers may well have received enquiries from him when things didn’t look correct.

We wish him well in his retirement and look forward to seeing him out collecting valuable ringing data in due course, now he has all this time on his hands. However he is a glutton for punishment, and he has agreed to take over the (unpaid) role of EURING Databank Manager from Chris du Feu in 2017. So he will keep his brain working and we will still have contact with him.

23 September 2016

A splash of gold

Back in March BTO Ringer Roy Pearson ringed a Goldcrest in his garden and has recently received some exciting news about his Goldcrest.

At 09:00 on 25/03/2016, I ringed a female Goldcrest in my garden in Boston, Lincolnshire. The bird weighed 6.9g.

Female Goldcrest. Photo taken by Anne Carrington-Cotton

This was subsequently caught by a ringer at 08:00 on 02/04/2016 at Griefswalder Oie, Mecklenburg-Vorpommern, Germany.  This is close to the Baltic Sea and the Polish border, a distance of 931 km from where it was ringed (see map below). The duration was an amazing 8 days.

This is all the more remarkable as I ring very few Goldcrests in the Fens and is only the second recovery of this species in nearly fifty years of ringing.  The other recovery was also this year, but on this occasion the distance covered was merely a few hundred metres.
Eds write:
A ringer is nearly twice as likely to catch a foreign ringed Goldcrest in this country than to have a BTO ringed one found abroad. Around 22% of BTO-ringed foreign recoveries are found in The Netherlands followed by France (19%), then Belgium (16%). The bird in Roy's report is also one of the most-travelled BTO-ringed Goldcrests.
In a month's time we should reach the peak in Goldcrest sightings, as shown by BirdTrack (below); the sightings are currently following a similar reporting rate to last year (however there was an unusually high number of birds reported last October as previously posted). So if you see a ringed Goldcrest and are up for a challenge, have a go at reading the ring (usually 6 digits). It might have words like 'Norway or 'Sweden' as well.

13 September 2016

Who ringed the Plover?

The BTO Online Reports map for Ringed Plover shows a very broad distribution of recoveries of birds that visited Britain or Ireland at some stage during the year. By looking in detail at the time of year they were ringed and subsequently found, we can start to tease apart what is going on. Thanks to the Gulf stream making our shores relatively warmer than those further north, thousands of small waders winter here and some birds that have bred here move south to winter in France, Spain and even Africa.

Ringed Plover recoveries. Purple: ringed in Britain & Ireland, Orange: found in Britain & Ireland

At this time of year there will be a mix of birds moving south and birds that have just arrived. Telling the difference between these is where ringing comes into its own. As we have posted previously, Lee Collins spends hours throughout the year looking at birds' legs at Dawlish Warren. One of his recent finds included this colour-ringed Ringed Plover (below).

Ringed Plover - photo by Lee Collins
After a little searching it became clear that this bird was ringed 42 days previously at Dufour River, Byulot Island, Canada! This is currently the second report on our system of a Ringed Plover from Canada. This bird was ringed while 'he' had an active nest with eggs (which hatched two days later), so assuming they were not predated, he must have made a very quick trip to Dawlish Warren from Canada. He was one of 73 birds fitted with a geolocator. When these birds arrive back in Canada, and Don-Jean Leandri-Breton resumes his nest study, hopefully the retrieved geolocators will provide information on when and where these birds have been since the geolocator was added.

To get the full effect of how remote the ringing location is, just zoom out of the map below.

Photo taken by Don-Jean LĂ©andri-Breton

Photo taken by Don-Jean LĂ©andri-Breton

For more information see the Dawlish Warren blog.

30 August 2016

Ringing on Fair Isle

Ciaran Hatsell, Senior Assistant Warden for Fair Isle Bird Observatory (FIBO) writes:

Fair Isle has been a hallowed ground for ornithological studies for over 60 years. It's unique location and isolation coupled with its small size make it a nigh on perfect place to study both bird migration and seabird populations. With the old pioneers such as ‘Fieldy’ Stout paving the way for the modern day observatory staff (who rely more on optical equipment than firearms!), the art of daily observations and recording still holds a very relevant place in the ornithological world.

Fair Isle is famous for attracting rare and scarce migrants from all over the world and the daily ringing activities often provide opportunities to study some unusual species. With over 378,000 birds ringed at FIBO, there have been some remarkable movements logged, with ringed birds recovered as far away as Brazil, Canada, Russia and South Africa amongst others.

It would be easy to assume that the majority of the ‘vagrants’ that reach the isle will never make it back and that they have simply made a grave error on their migration route. However, down the years recoveries have shown that birds can re-orientate and get back on track. A Rustic Bunting ringed on 12th June 1963 on Fair Isle was shot in Greece on 15 October of the same year, demonstrating the ability of these birds breeding hundreds of miles from here to find their way again (albeit to meet an unfortunate end!)

American Wigeon photo taken by Edmund Fellowes

Another phenomenal tale was of a young male American Wigeon, ringed as a duckling in New Brunswick, Canada on 13 August 1986 and found on Fair Isle 21 September of the same year! In a recurring theme, the bird was then shot two months later in Ireland, presumably as it attempted to re-orientate. 

Fair Isle has been fortunate enough to host many first records for Britain over the years and birding here really can produce anything at any time: from a Rufous-tailed Robin (the first British record) being found on a family stroll, to a Magnolia Warbler found on the cavernous expanses of the west cliffs of the island on a Sunday afternoon off. It really is a magical place to observe migration. For those islanders and Bird Obs staff that value their ‘Fair Isle lists’, it can be the most unusual bird that gets people running. Several observers famously abandoned a search for a Siberian Rubythroat to go and see a Blue Tit that had turned up!

A super rare Blue Tit photo taken by Dawn Balmer

The other major aspect of work at FIBO is the monitoring of seabirds. The fortunes of Fair Isle’s seabirds play out a rather sinister tale and in recent years, the island have been a crucial biological indicator site of our changing climate. Several species have declined in number and the demise of the Kittiwake is perhaps the most evocative story. They have gone from 19,340 breeding pairs in 1988 down to just 880 breeding pairs in 2015.  The islanders who have been here since then are saddened by the lack of noise and atmosphere the Kittiwake once created, with the voice of the Kittiwake fast disappearing from our seabird choir.

Kittiwake photo taken by John Harding

There has been a great amount of work recently done on designating the waters around Fair Isle as a Marine Protected Area (MPA), which could potentially go some way to safeguarding the future of Fair Isle's seabird and marine life.

As part of the seabird monitoring work here we also get a chance to ring a good number of seabirds. One of the aspects visitors to Fair Isle often enjoy the most is the Storm Petrel ringing sessions. The opportunity for guests to get involved with releasing the birds is something people rarely forget and makes a trip to Fair Isle even more memorable. It never ceases to amaze how these dainty, Starling sized birds spend years out on the open oceans, covering great distances in the search of food and potential breeding colonies. The BTO website lists the oldest Storm Petrel at 37 years, 11 days old, remarkable for such a diminutive seabird! Fair Isle a great site for catching, with 2,453 birds ringed in 2014 alone. We have caught birds from the Faroes, Norway, Portugal as well as many hundreds from other sites in Britain.

The standardised daily recording and ringing of migrants provides a fantastic and unique data set. The data is currently being analysed with some fascinating results involving the arrival and departure dates for migrants. There is a vast wealth of data and it may take many years to analyse it all.

Over anything else, it is a great honour and privilege to get to work in such an incredible place, with the changing of the seasons bringing something new at every turn. From migrants, to seabirds to taking in the awe inspiring scenery, the work here at the Bird Obs is both scientifically relevant and hugely enjoyable.

Eds - It is great to see a report of the first ringed Hen Harrier being recorded moving to/from Fair Isle! Ringed as a chick on Orkney on 7 July. See more on their Twitter page.

15 August 2016

An unexpected but timely recovery

Gary Clewely (BTO) writes:

Nightingales are one of the best-known species in the UK for their impressive vocalisations, yet will be increasingly unfamiliar to many of us due to a marked range contraction and population decline in recent decades.

The motivation behind the BTO Nightingale tracking study is to identify key migratory routes and wintering areas to inform conservation. Fieldwork during the 2016 Spring was particularly exciting, because in addition to retrieving geolocators from previous years, this was the first time GPS loggers weighing less than 1 g were fitted to Nightingales in the UK, which if recovered the following year would give us unparalleled data on their migration.

Nightingale. Photo taken by John Spaull

During a mist-netting session at Alton Water (blue pin on map), in Suffolk (managed by Anglian Water, one of the tracking study partners) where we were catching males for tagging, one of the birds caught was already carrying a BTO metal ring – NA82699. This was initially not too unusual, especially as ringing was taking place on the site. The bird was swiftly processed and fitted with a GPS tag before being released safely back into its territory. Later, it came to light that NA82699 had in fact been ringed in January 2016 during an expedition to the Kartong Bird Observatory in The Gambia (orange pin on map). This is the first case of a Nightingale ringed in sub-Saharan Africa being found in the UK but remarkably, it is not the first exchange of Nightingales between East Anglia and the Kartong survey area. In 2011 and 2012, Nightingales ringed in East Anglia were recorded in Kartong, including a bird originally from a site near Ipswich, just 10 km from Alton Water.

Of course, recoveries in and from Africa are hugely dependent on effort and are biased depending on where ringing activities take place. Nonetheless, it is extremely encouraging that the ongoing monitoring at places such as the Kartong Bird Observatory is valuable and well placed to help inform us about migrant bird populations.

Olly Fox, who was on the January trip to The Gambia, reports that the Kartong ringing survey has a relatively high retrap rate for Nightingales with four birds encountered in multiple winters (in addition to the three exchanges between Kartong and the UK) from only 17 birds ringed between 201115. Olly goes on to tell me that wintering Nightingales in the coastal part of The Gambia are generally found in patches of dense vegetation but can also occupy secondary habitat, such as disused farmland. For males at least, these territories are defended throughout the winter months. However, increasingly these habitats are under pressure from development of agriculture and clearance of woodland and scrub to satisfy a rise in demand for firewood and charcoal. These are perfect examples of land-use changes occurring across the range of many migrant species that are important to identify and understand when considering their conservation.

Nightingale singing. Photo taken by Amy Lewis

Far from jumping the gun on the tracking study results, recoveries such as this complement tracking well, providing useful context and help to focus winter ringing efforts and inform local conservation, in this case by the Gambian Department of Parks and Wildlife Management and other NGOs. We will still need the detailed tracking information to understand the precise routes taken and the timing of their movements. The combination of continued tracking work and further ringing in The Gambia will help us understand how typical the apparent connectivity of Nightingales between East Anglia and coastal Gambia is.

02 August 2016

Want to see a Whimbrel? Den mark it with a colour ring

It's always a pleasure to hear the Whimbrel's distinctive call when flying over and it's very special when one is caught (see online reports). Relatively few are ringed in Britain & Ireland and with the addition of colour rings the reporting rate has increased substantially. The pie chart below shows how few dead birds are found in relation to the number of reports received of colour rings.

The Mid Wales Ringing Group started a colour ringing project in 2010 to try to answer some basic questions regarding Welsh birds in particular, like movements, staging areas, survival and site faithfulness. Some of these birds have been reported (dead and alive) in quite a few areas including Scotland, France and North Africa.

A Whimbrel wearing a Mid Wales colour-ring combination was recently reported in Denmark. The BTO online reports show this to be only the fourth BTO-ringed Whimbrel to be reported in Denmark. Yellow D74 was ringed on 30 April 2016 at 2:50 am and 72 days later it had travelled a minimum distance of 1,059 km to Storevorde, Denmark.

If you were hoping to see a BTO-ringed Whimbrel outside Britain & Ireland, there is a much greater chance of seeing one in Guinea (195 reports), Guinea Bissau (224 reports) and Iceland (366 reports).

Colour-ringed Whimbrel photo taken by Jens Veilgaard Vendelbo
Whimbrel photo taken by Jens Veilgaard Vendelbo

So if you ever see a Whimbrel, or any other wild bird for that matter, report it at www.ring.ac. The information will be very useful and could hint towards a new movement or behaviour.

For more information on this and other Mid Wales goings on, click here.

18 July 2016

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

12 July 2016

Turtles migrating north

For many, the song of the Turtle Dove is synonymous with warm summer days in our countryside. Thetford Forest, Norfolk has traditionally been a great place to hear them purring; however over recent years it has become increasingly more difficult to find them. The 2015 Breeding Bird Survey (BBS) report, published recently, puts the decline into perspective "Turtle Dove down by 93% in the UK from 1995 to 2014!". The full BBS report highlights other declines, but also some big increases.

The decline in Turtle Dove is also noted in the ringing totals, with an average of c. 40 birds ringed in the whole country since 2010 (and only 12 in 2015) compared to an average of almost 140 in the 1980s. With so few birds ringed, the re-encounter rate of a Turtle Dove is very low, but however slim, there is always a chance to provide useful data.

Colour of location: Ringed in Britain & Ireland, Found HereRinged Here, Found in Britain & Ireland
The majority of the recoveries of Turtle Dove have been in Portugal, Spain and France with just four sub-Saharan records. Soon the map above will need to be updated to show the 2016 records of a BTO-ringed Turtle Dove being found on the Faeroes! This second year Turtle Dove (below) was ringed on 23 May 2016 on Fair Isle only to be seen alive and the ring read on 30 June 2016 at Vidarlundin Park, Torshavn.

Turtle Dove on Fair Isle about to make another epic journey North. Photo taken by Lee Gregory.
Not only is this an exciting report for Fair Isle (the only other previous recoveries of this species were of a bird caught on 5th May 1982, which was shot in Spain on 01 September 1982, and another ringed on 6th June 1974, which was shot in France on 4th September 1977) but it is also a great report for the whole of Britain & Ireland. It is great to hear that this bird wasn't shot or found dead either.

Thanks to David Parnaby and the rest of the Fair Isle Bird observatory team for highlighting this.

07 June 2016

Two broods are better than one

Hazel Evans, NRS secretary writes:

Studies in Europe demonstrate that Great Tits have the potential to produce two broods per season; a recent study of populations in The Netherlands showed that over 50% of birds were double-brooded in the 1960s, though this number has been declining as the climate warms. Despite this observation, records of double-brooded Great Tits are still relatively scarce in the UK – is this because it is truly a rare behaviour or because we’re so used to thinking of them as single-brooded that we don’t often check our boxes after the first chicks have left?

Robin and Moya Myerscough from Norfolk have been keeping a very detailed log of the comings and goings at their garden in nest box during 2016. A female Great Tit began laying on 6th April and completed a clutch of nine, which hatched on the 27th. Unfortunately two chicks died but the remaining seven fledged successfully at 08.15 on 17th May.

Female Great Tit collecting nesting material. Photo taken by Jill Packenham

These observations constitute a great record for the BTO’s Nest Record Scheme but nothing seemed particularly out of the ordinary. However, by 2 pm an adult was bringing in fresh nesting material and it laid the first egg of a second clutch the very next day.  This in itself is unusual, but a gap of less than 24 hours between attempts seems amazing. Great Tit fledglings are heavily dependent on their parents for about a week after leaving the nest but it is possible the female was able to juggle these responsibilities with laying of the second clutch, given incubation does not commence until the penultimate egg is laid.

Great Tit removing a fecal sac. Photo taken by David Waistell

In truth, while it seems rapid, we don’t really know just how this observation compares to the typical interval between broods, but the widespread use of nest box cameras has the potential to significantly increase the amount of information we are able to collect. Whether you own a camera or not, it’s worth keeping a close eye on your nest boxes over the next couple of weeks to check for second broods – remember to submit records of any attempts you find  to  the Nest Record Scheme or Nest Box Challenge.

27 May 2016

Elderly Shag strengthens our position in Europe!

Jim Lennon from the Shiants Auk Ringing Group writes:

Ringing seabirds can be mucky and challenging work, especially when you’re ducking under a rock to reach a Shag chick, while keeping an eye out for its protective parents (often the croaking male). However, this is soon forgotten when you receive news of one of them nearly 31 years later!

Shag chick 1227282 was one of a brood of three ringed on the Shiants Isles, Western Isles, on 30 June 1985 by Ms Sam Powell, a trainee ringer from South Wales working with the Shiants Auk Ringing Group. A total of 725 pulli from 377 broods was ringed on the Shiants that year.  Most of the subsequent recoveries were of birds that perished within the first 12 months, a few survived for four or five years and an exceptional bird was found dead after nine years.

But 1227282 outlived them all by a country mile.  For the next 30 years following ringing, it most likely spent its life breeding on the Shiants and in the waters of West Scotland, but we’ll never know for sure as it was never heard of again until John Taynton, a RSPB worker on the Shiants, found it freshly dead on 26 April 2016 i.e. a life span of 30 years 302 days.

According to the BTO’s latest longevity list (2014), this makes the Shiants bird the oldest ringed Shag in Britain & Ireland, and also in Europe (see Euring), raising the record by nearly a year.

The Euring information is not updated as regularly as the BTOs longevity lists because it needs to access all the data from all the Euring ringing schemes and this can take some time.  It currently indicates that a 34 yr old bird from the Shiants is Europe's oldest  Puffin but two just shy of 36 years old and one almost 37 years old, are listed on the BTO longevity records site.

16 May 2016

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.

12 April 2016

Do Blue Tits move very far?... Generally no.

Ian and Sally Hunter from the Sandwich Bay Bird Observatory write:

Small groups of Blue or Great Tits, with the occasional Coal Tit, moving southwards along the seafront are not uncommon during visible migration observation at Sandwich Bay.

Despite 10,381 Blue Tits having being ringed by the observatory, we have not really discovered much about their movements. Until 23rd March 2016 the observatory only had one foreign control (ringed abroad), from the Netherlands, and one foreign recovery (found abroad), to the Pas de Calais region of France. Other movements were usually within Kent (19 birds), mostly to/from coastal sites, with six to/from other southern counties. The BTO ringing scheme as a whole has only had an extremely small number crossing the channel.

Blue Tit recoveries involving Britain & Ireland
Colour of location: Ringed in Britain & Ireland, Found Here; Ringed Here, Found in Britain & Ireland
So when a Blue Tit wearing a Lithuanian ring was captured, there was plenty of excitement. The bird was noticeably brighter blue than local birds. Its wing was a big 70 mm and it weighed 11 grams (average for British Blue Tit is 63mm wing and 10 grams). Interestingly the previous day a white headed northern race Long-tailed Tit had been observed and two days later a continental Coal Tit was ringed.

Lithuanian Blue Tit. Photo by Becky Johnson
The map below shows just how far this bird has travelled from Ventes Ragas, Silute distr. It was ringed as an adult Blue Tit at 13:00 on 15 Sept 2015 (nearly 1,400 km in about 6 months).

08 April 2016

First British-ringed Stonechat for Norway - rubicolus?

John Secker from Thetford Forest Ringing Group writes:

Since 2003, Stonechat breeding in the Forestry Commission’s Thetford forest on the Norfolk/Suffolk border have been surveyed. The population has been as high as 56 pairs (2008, after a run of mild winters), and down to just four pairs (2014 after a run of relatively cold winters). In 2006 a project to find nests, and colour-ring both chicks and adults was begun by Thetford Forest Ringing Group.  In total, 750 birds have since been fitted with combinations of three colour rings and a metal BTO ring; 673 have been nestlings, 37 adults and 20 fledglings.

There have been many re-sightings within the forest area and Breckland generally, but also eight from further afield, mostly within East Anglia. The furthest travelled bird being seen near Chingford, East London. But certainly, nothing prepared us for what was to come.

Stonechat - photo taken by Odd Kindburg in Norway

On 27 March 2016 two birders (Odd Kindberg and Fredrik Tjessem) photographed, and reported to the BTO, a colour-ringed female Stonechat, near Tangvall, Sogne, in Southern Norway. The bird had a pink ring above a pale blue on the left leg and metal above pale blue on the right. The combination certainly matched one used in Thetford Forest but all the same, although we could not find any other studies that might have used this combination, we had to wonder whether or not someone closer to Norway may have colour ringing this bird. But from what we could make out from the photos, the metal ring did look tantalisingly like a BTO ring. We got back in touch with the photographers and in no time at all Odd was back on the case and we soon received a new batch of excellent photographs that enabled the entire ring number to be pieced together and therefore rule out any confusion with other studies – BINGO!.

Records showed that this bird was from a nest found by Gavin Chambers in May 2015 near Grimes Graves in Thetford Forest, Norfolk. The chicks were ringed by Ron Hoblyn and me, and the nest fledged successfully. Tangvall is approximately 750 kms North-east of Grimes Graves.
None of the other birds recorded away from Breckland has moved in a north-east or easterly direction.

This is the first ever British-ringed Stonechat to have been reported from Norway. Stonechat was not found breeding in Norway until the 1970’s, when a population of the British race, Saxicola rubicola hibernans established itself. It was speculated that those birds were of Scottish origin, Scotland being the closest part of Britain to southern Norway. But maybe this new record suggests an alternative.

Stonechat showing the three coloured rings - photo by Odd Kindburg

It is possible that the bird became caught up in one of the powerful south-westerly storms that have swept Britain this winter, but perhaps more likely that it made the shorter crossing to the Netherlands and then moved north into Norway. Either way it is a fantastic record and demonstrates the possible rewards to be had from colour-ringing birds.

It will be interesting to find out whether or not this individual stays to breed in Norway.

23 March 2016

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).

07 March 2016

Getting more from your birding

Here at the BTO we engage with countless local birders as well as ringers and nest recorders. A lot of important work is undertaken by birders across the length and breadth of Britain & Ireland. One such birder is Lee Collins who writes:

My local patch at Dawlish Warren NNR in South Devon has, over the last three years, achieved some amazing success in generating large numbers of field reads of gulls, terns and waders; my efforts over 2014 were summarized on the Demog blog in May 2015. I am not a ringer, in fact no ringing is currently done on the site (although some ringing was done previously), yet with a positive mind-set, high on-site attendance accompanied with bundles of enthusiasm, anyone can achieve amazing results with ring reading.

Dawlish Warren NNR is a coastal reserve with a  long and rich history in birding terms and I'm proud to have called this my local patch since 1984. On-site breeding of gulls, terns and waders is non-existent and thus ring reads are generally confined to the winter months, although the months of July and August do also provide a bumper opportunity with the onset of post breeding dispersal.

I have just finished writing a detailed 38 page article on my efforts over 2015. In total I've record 429 field reads, comprising 16 species and involving 219 different individuals. Here’s a brief resume of the highlights.

Dawlish Warren. Taken by Lee Collins

The standout single read was in securing my second ever Roseate Tern ring. This bird was ringed at Rockabill, Ireland in 2013 and the read may be the only recovery of this species in the Britain & Ireland during 2015 away from their breeding colonies. Terns are of particular interest to me and although no breeding occurs, I see good numbers of 200+ Sandwich Terns present during July and August. During this periods it is a hive of activity, with birds coming and going as they feed offshore and drop back in to roost or to feed their fledged young in front of the hide.

I made 61 reads during this nine week period, securing positive reads on 35 different individuals (30 adults and five juveniles). The reads were a combination of colour rings (15) and the more difficult to read metal ringed birds (20).

Frustratingly, not a single bird recorded on the site was to provide information on where they bred during 2015, although most probably nested several hundred kilometres away. Importantly, there is a good rate of multi-year observations of several individual birds recorded on-site during 2013 and 2014. The results suggest the Warren plays an important role as a staging and feeding area during post breeding dispersal.

Sandwich Tern taken by Lee Collins

The majority of Sandwich Tern ringing locations were in Scotland (750+ km away) and the Netherlands (600 km away), although others also range from Poland to Ireland. The Polish-ringed Sandwich Tern is particularly noteworthy as it looks to be the first recorded in Britain & Ireland.

Sanderling taken by Lee Collins

Waders are of particular importance and are abundant on the reserve. Sanderling in particular are of interest due to their long-distance migratory pattern and I found ten different colour ringed individuals during 2015. Most birds were seen during the month of May as they headed north to breeding grounds in Greenland. These birds were ringed in Greenland, Iceland or Mauritania.

Ringed Plover taken by Lee Collins

Ringed Plover is an abundant species in Devon, yet with a poor recovery history. I recorded seven in 2015, which is almost double the entire recovery history for the county. These were found during the autumn, presumably passage migrants dropping in to refuel. Unsurprisingly, a few were from Iceland, but several were from Norway and a one was from Germany.

Despite these impressive recoveries, my most important work is in fact dedicated to a species that receives little attention from practically all the birders that visit the site, the Oystercatcher. Over a three year period I have made almost 270 positive metal ring reads involving 116 different individuals, with 77 different birds recorded during 2015 alone.

The vast majority (91%) of these were ringed on-site, as part of a study programme undertaken between 1976 and 2004. The movements recorded may not be very far but this provides invaluable data on longevity and survival of this species, especially as it is now amber listed. I have recorded over a dozen individuals that were at least 25 years old, plus another that was ringed in 1983, making it at least 32 years old!

If you wish to read more, you can read Lee's full article on the Dawlish Warren blog.

26 February 2016

What happened to all the Jays?

Around the UK, Jays haven’t needed to dip into their large cache of acorns much this winter, with the weather being so mild. They will top up their diet with invertebrates and any other meaty treats they can get. This search can lead them to gardens during cold periods and some of these gardens are occupied by BTO ringers.

Jay taken by John Flowerday

Last year our BTO ringers ringed 506 Jays in the Britain & Ireland (c700 is the five year average) and as Jays can live to a maximum of 16 years old, there are a good number of ringed Jays in the wild population. Being very clever birds, they can provide a challenge to ringers to catch them but once caught they deserve respect as they are incredibly powerful birds with very sharp claws and beaks. Once in the ringers hands the birds are ringed, aged, and several measurements taken to record the condition the bird and if any moult or breeding is occurring.

Jay taken by Lee Barber

Thankfully 89% of the reports of ringed Jays come from our ringers by re-catching them, months or even years later. This information is vital to understanding the movements, behaviour and survival of this beautiful bird. Ringed Jays are also found by non-ringers, which usually report them through www.ring.ac website.

Most of these birds are just found dead with no cause of death given, however a large proportion are legally shot/trapped with the aim of reducing their impact on other species nesting attempts. The Jay is not without its own predators however, as 6% of ringed birds reported to the BTO have been taken by a predator. Even the Peregrine is a little partial to the odd Jay as a recent BTO Demog Blog post can testify.