17 December 2015

The twelve recoveries for Christmas

Partridge in a Pear Tree
There is no mention of a Pear tree on the BTO BirdFacts pages for Grey Partridge however we do have 127 recoveries for this species. Most of these recoveries are of shot birds, as you would expect, but we do have several that have been radio tagged and the mortalities reported. One of the predators of these is quite surprising. Click here to open this recovery

Two Turtle Doves
We have even fewer recoveries for Turtle Dove (101) on the system, due to a severe decline in numbers since the late-1970s. As a result, they are still on the 'Red List' of 'Birds of Conservation Concern'. These reports are mainly of birds found dead, shot or found after being killed by a predator but it is pleasing to see that 73 of these reports are from ringers re-catching ringed birds; helping to further understand their decline and movements.

Recoveries Of Turtle Dove for Britain & Ireland
You'd have to have good eyes to get this recovery. Click here to open this recovery

Three French Hens
Even though our Ringing Scheme doesn't ring chickens, it does ring the majestic Hen Harrier. There has been some great work in recent years on wing tagging Hen Harriers, increasing the life histories of these birds from their breeding quarters to their wintering areas. One bird getting an amazing 87 sightings compressed into just two years.

For our selected recovery, it has to be a French one though. Click here to open this recovery.

Four Calling Birds
At this time of year the Tawny Owl is starting to think about the up and coming breeding season and on those frosty nights, can be heard calling to each other. One recovery that you haven't seen the report for was a Tawny Owl ring found in Iceland! This caused some confusion here in the Ringing Team, as we have never had a foreign recovery of Tawny Owl. After much investigation we found out that this ring was put on a Tawny Owl chick, which died in the nest. This ring was collected (to avoid subsequent reporting) and put on the ringer's binoculars. After a binocular strap broke on a birding trip to Iceland, this ring was later found and reported to our Ringing Scheme.

Our chosen recovery however is different and is an unusual way to go. Click here to open this recovery.

Tawny Owl. Photograph taken by Lee Barber

Five Gold Rings
One of the highlights for 2015 were the numbers of Goldcrest caught. We posted previously just how good the Goldrush was.

The chosen recovery has links with the three French Hens. Click here to open this recovery to understand how.

Six Geese a-Laying
How can we not look at goose nest records after a title like this!? For 2015, the BTO Nest Record Scheme has received 108 Canada Goose, 49 Greylag Goose and seven Egyptian Goose nest records. This has remained stable but very low over the years. If you have any records please let the Nest Record Scheme know.

An amazing recovery from the Wildfowl & Wetland Trust. Click here to open this recovery.

Seven Swans a-Swimming
One of our highest reported groups of birds are swans. Being large, white and living in populated places they are easily found and reported. Many land on roads thinking they are rivers and being less maneuverable they do crash into wires, walls and bridges.

One of our Thetford, Norfolk colour ringed Mute Swans this morning, showing just how easy it is to get colour ring sightings. Photograph taken by Lee Barber
The Bewick's Swan is famous for it's migration route but this recovery points out they do live a long time. Click here to open this recovery of 28 years!

Eight Maids a-Milking
We were not able to find any maids in the BTO ringing database but there are quite a few cows mentioned. Unfortunately, it seems like they are not too keen on swans which can get trampled. We have a very different recovery involving a Sparrowhawk for our chosen recovery. Click here to open this recovery.

Nine Ladies Dancing
The Great Crested Grebe is famous for it's pair bonding display, where it rises out of the water and dances on the surface. Few grebes are ringed and even fewer are found later, giving a grand total of eight records to choose from. How the finder got this recovery is unknown but it probably took hours. Click here for the recovery.

Great Crested Grebe. Photograph taken by Chris Knights

Ten Lords a-Leaping
This may be a tenuous link but in the movie, 'Lord of the Rings', Gandalf leaps off Saruman's tower onto a Great Eagle. This looks remarkably like a Golden Eagle and we have 35 recoveries of this species. Click here to open this recovery.

Eleven Pipers Piping
Not 11 records of a Purple Sandpiper, but just one. This is the number of records we have of dead Purple Sandpipers. By re-catching 'purps' our valued ringers have increased the information on this species by 928 records. These include the data from a colour-ringing project in Norway which has produced an amazing 51 sightings in Britain & Ireland. Click here to open this recovery.

Twelve Drummers Drumming
The Snipe is famous for its drumming breeding display and we have received quite a few recoveries of this species over the years from 24 other countries. One of these was from one of our Constant Effort Sites (CES). Only one Snipe has been ringed at Cranwich CES to date and so far there is a 100% recovery rate for this species. Click here to open this recovery.

Measuring a Snipe. Photograph taken by Lee Barber
The Demography Team wishes you all a very Merry Christmas and happy New Year

08 December 2015

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

20 November 2015

Choppy times for Manxies

Manx Shearwaters and their migration provide one of the most fascinating bird stories of the British Isles. They breed in inaccessible places and historically have been difficult to observe, let alone study, outside their breeding period. For this reason, the Manx Shearwater has been a mysterious species for ornithologists for many years. Luckily, technology, the Ringing Scheme and the fact that it is a long lived species have combined to provide us with a lot of information on the life history of the Manx Shearwater, including its distribution and behaviour in summer and winter.

The 300,000 breeding pairs of Manx Shearwaters in Britain & Ireland are distributed among about 50 colonies, the largest ones being Skomer in Wales and Rum in Scotland. Several thousand 'Manxies' are ringed by BTO ringers every year; the table below show the last five years from the Online Ringing and Nest Recording Report.

Most 'regular' recoveries of Manx Shearwaters are generated at their breeding sites, when they return to breed at the same colonies year after year. Since the BTO Ringing Scheme started, over 100 years ago, we have received about 1,000 reports of BTO-ringed birds from foreign countries, all except one on the Atlantic coast, most of them in Brazil, Uruguay and Argentina. 

Nowadays, the more exciting and revealings facts about the pelagic life of this species come not from ringing but from satellite and datalogger tracking. When the birds return to breed in their burrows on islands in Britain & Ireland, they can be fitted with special devices that are safe for the birds and give more detailed information about their movements and behaviour.

Researchers studying this species have been able to reveal where most 'Manxies' spend their winters and what routes they take to and from the breeding colonies. One such research project is led by T Guilford - some result from which, below, show the estimated routes and stopovers of 12 birds fitted with geolocators. 

Different colours indicate different birds, the 'lines' are joined dots and do not represent actual trajectories of the birds. 
Migration and stopover in a small pelagic seabird, the Manx shearwater Puffinus puffinus: insights from machine learning
T GuilfordJ MeadeJ WillisR.A PhillipsD BoyleS RobertsM CollettRFreemanC.M Perrins
Most of the South American reports occur between November and January, and the number of dead birds reported along the coasts of the Atlantic varies from year to year. So far this Autumn we have received 10 reports, a few more than we would expect. Many of the finders who kindly let us know about these Manx Shearwaters mentioned the stormy weather they have experienced on the other side of the Atlantic. These intense stormy periods may be linked to a strong 'El Niño' event in the Pacific, bringing unusual weather to many parts of the world including North and South America. 'El Niño' literally translates as 'the child', because this weather anomaly typically manifests around Christmas time when the birth of baby Jesus (the child) is celebrated. The graph below puts the 2015 'El Niño' event in context compared to previous strong 'El Niño' events.

The graph above shows how this year's event ranks in terms of severity compared to other strong 'El Niño' events. More information can be found at: http://www.srh.noaa.gov/tbw/?n=tampabayelninopage

It is also interesting to see how many birds have been reported washed up on the shores of the east Atlantic in the last two decades. 

In North America, Deaborah Kotzebue, who lives Texas, USA, found a Manx Shearwater in Gulf Shores, Alabama, washed up after a stormy period. She sent us some photographs to illustrate what the place is like

The other nine reports of Manx Shearwaters were of birds washed up on beaches in Brazil, South America. One of them was found on Campeche beach, Santa Catarina, by surfer Paulo Vieira. I asked Paulo if the weather had been particularly stormy and he replied "Yes, it has been very stormy  down here in Santa Catarina State, and southen Brazil in general. We are suffering the effects of 'El Niño', which produces a lot of rain during the Spring (above normal range). Since mid-September until early-November it has been raining a lot down here".

At the end of the wintering period we will give an update on Manx Shearwaters on the other side of the pond.

The Manx Shearwater was chosen as the bird of the month in September 2015. See the distribution map in the Atlas Mapstore.

16 November 2015

Out of Africa... and into Norfolk, for a 13 gram bird

Oliver Fox writes:

Monitoring of wintering passerines is one of the main objectives of the Kartong Bird Observatory (KBO), a project run by volunteer ringers in the south of The Gambia, West Africa. Situated on the Atlantic coast close to the Senegalese border, the Kartong wetlands were formed relatively recently as a result of wet-season flooding of disused sand mines and form part of the Allahein to Kartong coast IBA.

Palearctic passerines being processed at Kartong Bird Observatory taken by Colin cross

The wetland reedbeds and surrounding scrub provides an excellent wintering site for many Palearctic passerines, and mist-net surveys have highlighted the importance of the site for Western Olivaceous Warblers, Common Whitethroats, Subalpine Warblers and Common Nightingales in particular. In dry years the area provides refuge for Sahel-dependent species, such as Western Orphean Warblers and Woodchat Shrikes, when conditions further north become unfavourable. Located on a promontory extending into the Atlantic, the site is also well placed to observe passage migration of Blackcaps and Garden Warblers moving south in October and November and Willow Warblers moving north in early Spring.

Wintering Reed Warblers are regularly encountered at Kartong, both in the Typhus reedbeds and the dry coastal and Acacia scrub that surrounds the wetlands. A proportion of those ringed at Kartong seem to be faithful to the wintering site, with five birds recaptured the winter after ringing and one bird returning to Kartong in two successive winters.

Reed Warbler about to be released at Kartong taken by Oliver Fox

News from the BTO has been received that a Reed Warbler ringed on 18/01/14 at Kartong was recaught at Hilgay Wetland Creation, Norfolk on 11/08/2015 BTO's Graham Austin, only 29 km from BTO HQ. There were several BTO staff members on the expedition in 2014, so it seems fitting that the bird was caught in Norfolk a few months later.

This is the sixth Reed Warbler ringed at KBO to be recaptured back in Europe during the summer months, with three having been previously recaptured in Spain, one on Guernsey and one in Surrey. Similarly, the ringing teams at Kartong have recaptured two Spanish and one British & Irish-ringed bird in the last few years, showing the migration pattern of Reed Warblers from Western Europe to the coast of West Africa.

Details of this latest recovery can be found on the Recoveries and Controls page of the KBO website.

29 October 2015

The Goldrush: update

After the big influx that we reported previously on the Demog Blog, and on our very own BTO Bird Migration Blog, things have calmed down somewhat after the initial rush (see BirdTrack chart below). For our ringers however, it's time to start inputting all that data scrupulously collected including age, sex, date, time, location, wing length, weight and fat and muscle scores. 

Goldcrest reporting rate by BirdTrack

Once the BTO receives the data, they will be loaded and the ringer/finder should receive the details about these birds within a few days (as long as the original ringer has submitted the ringing data). If it's a foreign-ringed Goldcrest, the BTO will contact these schemes and exchange information. Just this morning we received a file from Daphne Watson from the Isle of Wight who caught a Belgian ringed Goldcrest and the details arrived with the Belgian Ringing Scheme only 3 hours later (isn't technology brilliant!). They send us the ringing details and we then pass the information onto Daphne.

Unusually pale Goldcrest lacking it's dark pigments taken by Euan Ferguson and Carmen Azahara

Pale Goldcrest compared to a more usual one, taken by Euan Ferguson and Carmen Azahara

Below is a map of the origins of all the Goldcrests ringed abroad that have been caught in Britain & Ireland within the last couple of weeks! There are bound to be a few more and they will arrive in due course, ready for the Online ringing report to be published next year.

Some of the origins of these Goldcrests are very notable, as we have only received a handful of reports from these locations in the last 106 years (it also takes a lot of Goldcrests to get a handful). For example this was the 15th Belgium-ringed, the eighth Polish-ringed and sixth Lithuanian-ringed Goldcrests reported here. Click on the red point to find out how many reports of Goldcrests there have been from each county.

22 October 2015

Getting collared by a goose

Geese are one a special group of birds that can divide people's opinion in the same way that city pigeons or urban gulls can. Many assume that geese stay in the same place year after year, especially the ones that are fed in parks and urban areas. No one really knows for sure however and ringing is uniquely set up to be able to find this out.

Canada Geese taken by John Harding

One particular issue people have is that when geese moult during June or July, they drop all their flight feathers simultaneously and become flightless. Due to the fear of predation they remain very close to bodies of water for the month or so while they regrow their feathers. Geese can cause serious habitat degradation in certain locations like the reed beds at Hickling Board, Norfolk (.pdf) and understanding more about the reasons behind this can improve the situation for geese and people.

On our BTO Nunnery Lakes reserve, Thetford, Norfolk we have several fishing lakes and the geese usually choose the lake that has fencing around it. The downside of this decision is that the geese quickly eat all the accessible food and they have to be moved out onto another lake. During this process the geese are ringed, and in 2012 our ringers started to add uniquely coded plastic neck collars to Greylag and Canada Geese as part of the Hickling Broad project.

Canada Goose AEL - taken by Neil Calbrade

Neck collars are a safe marking method for large geese and have been used widely in previous studies on species such as the migratory Pink-footed Goose and White-fronted Goose, allowing individuals to be identified when on water as well as on land. This is particularly important if you are investigating moulting birds, where seeing their legs are an issue. Due to the size of the goose's head the collars actually have quite a lot of room inside to move around.

Greylag FHA bringing up the next generation - taken by Janet Foster

Since 2012, we have had a fantastic response from BTO staff, volunteers and members of the public who have submitted sightings of any geese with neck collars to www.ring.ac, specifying the species, combination on the colour ring, location (ideally with a grid reference) and the date.

The map below shows the sightings that we received between summer 2012 to summer 2014 away from the reserve itself. As you can see they did indeed go into town but also they explored the surrounding waterways and lakes.

What is amazing however, is after the summer of 2014 the geese were spotted much further away from the BTO reserve, see map below. The reason for this are under investigation and some individuals regularly return to the BTO after making these 'unusual' movements. Being able to identify each individual on the water should help us answer some interesting questions like 'do geese moult in the same place every year', 'do they winter in the same locations' and 'why do they move'.

If you do see a neck collared goose, please report it via www.ring.ac and you will receive information on the movements of that particular goose and at the same time increase our understanding of these birds.

13 October 2015

The Goldrush

With all the excitement of the Yellow-browed Warbler influx at the moment, from Shetland to Cornwall, it could be easy to overlook the fact that Goldcrest is also doing very well (see the reporting rates on BirdTrack below). Weighing about 6g, this tiny bird was thought to ride on the backs of Woodcock to our shores (as they arrived at a similar time to Goldcrest) from Scandinavia and the Continent because they wouldn't be able to make it on their own; hence the old name of 'Woodcock pilot'. We now know this is not the case and they can make these massive migrations all on their own.

Ringers all over the country have been catching large numbers of Goldcrest with 150 ringed at Landguard Bird Observatory and 485 ringed at Spurn Bird Observatory over the last three days. This would be a small fraction of the number of birds actually moving through, as the 1,000+ estimate at Gibraltar Bird Observatory on one day can testify.

We have heard that a few have been caught wearing rings from different countries, for example the Mid Lincs Ringing Group caught a Goldcrest ringed in Denmark and a Polish-ringed bird was caught by Tees Ringing Group and Sandwich Bay Bird Observatory caught a Dutch and Latvian ringed Goldcrest. Mike Marsh and his team from Orfordness Nature Reserve managed to catch 109 Goldcrest last Sunday (11 Oct) and one of them was ringed on 6 October at Falsterbo Ringing Station, Sweden! Amazingly, the ring number was TM3052, which, if you put this as a grid reference on an OS 1km map, is only 15km from where the bird was caught. We don't believe this Goldcrest was pre-programmed to go here!

Goldcrest from Sweden. Image of ring taken by several photos of ring merged. By Dave Crawshaw

There are bound to have been more foreign Goldcrest captures over the past few days so feel free to share your stories below in the comments box.

01 October 2015

Phylosc's, Acro's and lovely lady Sylvia

Adam Homer writes:

The numbers of warblers ringed at Stanford Reservoir, Northants has increased significantly over the last 5 years. An annual habitat management plan allows us to control tall scrub which then allows low scrub and vegetation such as Brambles, Hawthorn, Sedge and Phragmites to regenerate. This as we all know is very important habitat for breeding birds such as warblers.

A site that is as far inland from any coastal observatory that you could get, Stanford Ringing Group prides itself on the numbers of warblers caught annually. Over 3,600 warblers were ringed in 2014 and already this year we have ringed nearly 3,800 and we still have October to catch a few more Blackcap and Chiffchaff.

With all these warblers ringed and eventually setting off on their migration we do receive a few reports of birds controlled (caught by another ringer >5km from ringing site) and we occasionally control birds ringed at other sites. Every spring we also retrap some of our returning warblers and to me that is what bird ringing is all about. That a small bird such as a Garden Warbler or Willow Warbler can fly a round trip of 3,000 miles and return to the site it has been breeding at for 10 years in a row is amazing!

Garden Warbler taken by Lee Barber (tail obscured)

One of these record-breakers was once again retrapped this year. It was a Garden Warbler that was ringed as an adult female on 2 July 2005. She then disappeared for two years, returning in 2008 and retrapped every year since. I was on holiday when she returned this year and was caught during two of our CES sessions. On 8 August she became the longest known BTO-ringed Garden Warbler at 10yrs and 37 days, breaking the longevity record for this species by 7 days*.













Garden Warbler












Lesser Whitethroat












Sedge Warbler






Grasshopper Warbler






Reed Warbler






Willow Warbler













As you can see from the table above, the numbers of warblers, particularly Blackcap and Chiffchaff, have increased significantly with Garden Warbler and Lesser Whitethroat also showing a positive upward trend.

*Eds - The longevity records will be updated when all the 2015 data has been sent to the Ringing Scheme and fully processed. This longevity record will then replace the previous longevity record... unless another ringer catches an older bird or Stanford Ringing Group catch this Garden Warbler again a few days older.

24 September 2015

Exceptional Siskin Surge

The Siskin movement this autumn has been exceptional, for both the early start and vast numbers involved, as indicated by BirdTrack. With the peak movement and arrival of continental birds still to come, numbers in the UK are expected to increase considerably.

BirdTrack Siskin reporting rate

Jeff Kew from Thetford, Norfolk writes:

This has been an exceptional September for Siskins in the UK, with large numbers being reported across southern Britain, due to a major irruption from Northern Britain.

Last autumn Siskins were fairly scare in Southern England with a few being reported on feeders in February and March, the usual peak time to see and ring this species. Reports from Scotland indicate a bumper cone crop last summer and consequently most Siskins stayed at home for the winter, this Autumn with dwindling food supplies the picture is very different.

In the Norfolk / Suffolk Brecks area we have not seen anything like the numbers coming to feeding stations in September since 2005.

In our Thetford garden we have already ringed 611 Siskins this month (in just 4 ringing sessions), with an amazing 368 caught on the 18 September.

One of the hundreds of Siskins recorded taken by Jeff Kew

We have had birds ranging from exceptionally light (10.4g) to exceptionally heavy (17.0g) - which presumably indicates a mix of recently arrived birds and birds with serious intent to travel much further south. The majority are juveniles, which appear to have done less post juvenile moult than our local breeders.

Post juvenile moult strategies are interesting with the amount of post juvenile moult being variable and probably linked to both fledging date and food supply. We believe unmoulted juveniles (3JJ) can reach us from Scotland.

Thinking back to what we saw in 2005 we had high numbers through September, followed by two recoveries in Spain in Navarra and on Mallorca - which could give an indication of where some birds of this years birds may end up this winter.

Greg Conway from Thetford Forest Ringing Group writes:

The extent of post juvenile moult is highly variable, with some typically retaining one, or more, old greater coverts along with juvenile tertials and tail feathers, whereas others replace all coverts, tertials and tail (see below).  However, there are also many in between that replace different numbers of tertials and tail, often symmetrically but not always centrally!

Juvenile Siskin with replaced greater coverts, tail and tertials - Greg Conway

Juvenile Siskin with replaced greater coverts and two inner tertials - Greg Conway
Juvenile Siskin that has replaced outer pair and 2 central pairs of tail feathers contrasting with juvenile feathers (pointed and browner) - Greg Conway

To better understand the mix of different migration and post juvenile moult strategies occurring this autumn, and add to long-term data collected from Thetford Forest, ​any ringers catching Siskins are encouraged to record the following biometrics (in addition to age/sex, wing & weight):

All birds if possible!
1) Number of unmoulted greater coverts (including those with zero)
2) Fat score (0-8 scale)​

And if time allows!
3) Tertial moult (record in IPMR moult card)
4) Tail moult (record in IPMR moult card)
5) Pectoral muscle score (0-3 scale)