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

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 Guilford, J Meade, J Willis, R.A Phillips, D Boyle, S Roberts, M Collett, RFreeman, C.M PerrinsProc. R. Soc. B 2009 276 1215-1223; DOI: 10.1098/rspb.2008.1577. Published 24 February 2009

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.

Icky went to Belgium

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

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

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

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

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



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