24 December 2014

Merry Christmas from the Demography Team

As we move closer to Christmas, many bird ringers will still be out collecting valuable data on our bird populations across a range of habitats, from gardens, woods and farms to salt marshes and estuaries. Winter ringing tells us a lot about the survival and movements of birds in response to weather and can also be used to assess the breeding success of birds that nest outside the UK, such as wildfowl and waders. We've received information about just over 763,000 ringed in Britain & Ireland during 2014, which is 55,000 more than this time last year, and expect many more records to arrive over the next few weeks.

Coal Tit - Lee Barber

This period of the year is a little quieter for nest recorders, although those out monitoring Barn Owl second broods will have only just laid their ladders down after an incredibly prolific season. With temperatures above average for the time of year, however, it's always a good idea to keep an eye out for signs of opportunistic nesting behaviour, particularly in gardens and around towns where the climate tends to be warmer and many homeowners are providing extra food. Data from this summer are still flooding into the Nest Record Scheme thanks to the amazing efforts of our volunteers, and we've received over 36,000 nest histories so far, over 2,000 more than at this stage last year. As with the results generated by ringers, this information will be used to improve our understanding of the role that survival and breeding success play in driving population trends.

BTO Blue Tits - Sue Lawrence

On behalf of the birds and the BTO, we would like to thank all our ringers and nest recorders for their support and hard work during the year, and all readers of this blog for your interest in, and support of, these vital surveys. If you're not yet involved and fancy making bird surveying one of your resolutions for 2015, why not have a look on our survey pages to find an option that suits you?

Merry Christmas and a Happy New Year from all of us at BTO HQ!

18 December 2014

Yellow legs and Black heads in Switzerland

We recently received a partial ring-read of a Black-headed Gull in Switzerland which did look to be a BTO-ringed bird, so definitely one worth chasing up! A few emails later and a week after first seeing the bird at Morges, Franck Lehmans was able to read the ring again and get the full number (EX70855); a bird ringed as an adult at Pitsea Landfill Site in October 2012.

This is only the second report of a British-ringed Black-headed Gull in Switzerland, following a bird ringed as a chick in Essex in 1999 and seen in December that year. The map below shows all movements of Black-headed Gulls to/from Britain & Ireland, from the Online Ringing Report.

Franck has a bit of a track record finding North Thames Gull Group birds: in April/May 2014 he reported a Yellow-legged Gull (Orange YY5T) originally ringed at Rainham Tip in February 2014. This bird also has an interesting history, being seen just five days after ringing in France, before moving on to Switzerland.

Wanderings of Orange YY5T
To top the story, in the same week that Franck was watching the Pitsea Black-headed Gull in Switzerland, the Yellow-legged Gull he'd seen in the spring was back at Pitsea, photographed by Richard Bonser (check out his excellent blog here)!

Orange YY5T at Pitsea Landfill on 29th November (c) Richard Bonser
Many thanks to North Thames Gull Group for sending on the details of these birds and for letting us use the map from their excellent website.

15 December 2014

Migration Mapping Tool

There has been a lot of discussion recently around the value of bird ringing. Ringing collects data on survival, productivity and abundance and this information helps scientists understand species declines, allowing them to prioritise conservation efforts. While the scientific benefits of ringing are relatively easy to see, the more practical applications of ringing are sometimes less obvious.

In November 2014, Highly Pathogenic Avian Influenza (HPAI) H5N8 was confirmed on a farm in Yorkshire. Guidance was updated on the BTO website and includes information about how to report any unusual mortality in wild bird populations.

Common Teal, one of the species analysed by the Migration Mapping Tool.
Photograph by Edmund Fellowes
During the previous outbreak in 2007, movement data collected over the last 100 years from birds ringed across Europe were collated by EURING to produce the Migration Mapping Tool. This maps migration routes in time and space for 21 species of water-bird. The tool was developed to assess the potential risk of AI being moved by wild birds; of course, other possible mechanisms of movement also have to be considered. It provides a summary of bird movements between different areas in Europe and at different times and demonstrates how useful data from bird ringing can be in a wider context. As well as being a valuable tool in the assessment of possible risk from the movement of AI, the Migration Mapping Tool is a fascinating resource for learning more about migration in general.

08 December 2014

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.