The Big Biggleswade Starling RAS

Denise Cooper-Kiddle and Derek Gruar write:

The BTO Breeding Bird Survey survey has recorded a 49% decline in Starlings across the UK since 1995. Why numbers have dropped so dramatically is not fully known. Retrapping Adults for Survival (RAS) projects are helping find out whether adult mortality is a possible cause.


Adult Starling. Photo by John Harding



My back garden in Biggleswade, Bedfordshire gets more than its fair share of Starlings (4,446 ringed here since 2010). Three years ago, the BTO suggested I should start a RAS project. As well as a unique metal ring I also add a colour ring to every adult bird caught between 1 April and 31 August each year. Since then I’ve colour ringed 634 adults. My RAS uses red rings with a white letter/number code starting with a P or a K and are unique to each Starling throughout Europe.

Starling roost. Photo by Laura Kuselska

What makes the Biggleswade RAS exceptional is the volume of data it produces. In June 2015, two months after the start of my first RAS season, I was contacted by a retired couple living a few streets away. They had started seeing Starlings with red rings in their garden and a leaflet they picked up in a local shop (1,000 had been distributed around the area) told them about the project. Brian and Viv took on Starling spotting as almost a ‘day job’ and Brian, an ex data manager, decided to set up and manage a complete project database. Every red-ringed bird is added into the database and every day on which that bird is sighted is recorded. This shows that an ‘amateur’ ringer and some absolute hero volunteers can provide a lot of information about a declining species.

So far the database contains 7,382 confirmed day sightings (ring code seen clearly among the mass of Starlings rushing around feeding). Looking at when individual birds were sighted shows that some birds are only seen during the breeding season and some are seen all year round.


Click to enlarge

Staying around or not, can make a lot of difference regarding the number of days on which a bird is sighted. Take two of the ‘regulars’ that have been seen on over 150 days since they were colour ringed. PIF has been seen on 158 days since being colour ringed on 4 May 2015. PVC has been seen 163 times, but wasn’t colour ringed until 14 June 2016. The difference is that PIF disappears for months at a time outside the RAS season and PVC has been seen on at least two days in every month since being colour ringed.

I did consider colour ringing the juveniles I catch as well, but decided against it as so few return as breeding adults the following year: of the 271 adults I have red ringed in 2017 only 52 had been metal ringed here as juveniles in 2016 (about 5% of the total of 980 juveniles ringed here in 2016). A lot will not have survived their first winter, but hopefully quite a few will simply have dispersed and gone elsewhere. It does look as if some birds return at some point because three Starlings metal ringed here in 2011 or 2012, and never seen or retrapped since 2012, suddenly turned up this year to ‘collect’ their red rings.

Juvenile Starling. Photo by Christine Matthews

Where do Starlings ringed in Biggleswade go? A number of recoveries and controls of birds within a 40 km radius suggests they disperse over a reasonable area. Two recoveries have been very noteworthy - a juvenile ringed here in August 2014 was found dead in Capel-Sylen, Carmarthen in March 2015 and an adult ringed here in November 2016 was found dead just outside Bunschoten-Spakenburg in the Netherlands in August 2017. This was especially interesting for me as I lived in Bunschoten-Spakenburg for 11 years; just one of those quirks of fate when investigating these fascinating birds.



With the 2017 RAS season now finished and the data entered into the database, who knows what the results will show us in the next few years. If you do see a red colour ringed Starling starting with the letters P or K, feel free to contact me on Info@denisecooper-kiddle.com.

From the land of ice and Blackcaps

For Hugh Insley, ringing at this time of year means, amongst many other things, trying to catch Siskins in his garden in Drummond, Inverness for his Retrapping Adults for Survival (RAS) project and so far this year he has caught 3,000. Inevitably, he also catches a few other birds which are not part of his RAS project.

On 11 July, he extracted a Blackcap from the net that was already wearing a ring. This wasn't one of the c. 50,000 that are ringed in Britain or Ireland every year though, but the first record of a Blackcap that was ringed in Iceland! Now the BTO has to add a new row to the long list of countries that Blackcaps have come from or have gone to with a connection to our ringing scheme.

Female Blackcap wearing an Icelandic ring. Photo by Hugh Insley.

As we have posted previously, Blackcaps have a very interesting and complex migration, possibly associated with climate change and supplementary feeding, which is currently being studied. Many of our British & Irish breeding birds are known to winter in the south, around Spain and Portugal, whilst those that now winter here are known to come from continental Europe - using a novel northwest migration rather than the typical southwest route to reach Iberia. 

The individual that Hugh caught was ringed on 3 November 2016 as a full grown adult female in the garden of the vicarage at Siglufjordur, N. Iceland (see the blue pin below). It was caught again twice more at the same location (on 20 January and 30 March 2017) before heading south to Inverness.

Blackcaps are a vagrant species in Iceland and only 222 have been ringed there; only five of these have been caught again in the country. Additionally, eight Blackcaps that were ringed abroad (five from Belgium and one each from Denmark, The Netherlands and France) have been caught in Iceland. 

 

So, was this a 'British bird' making a novel northwest instead of southwesterly (mirror-image migration) before returning to breed, or was it part of a wider northward movement now undertaken by central European Blackcaps into northern Europe?  

Ringing, recording and recoveries at Sandwich Bay

Steffan Walton, Assistant Warden at Sandwich Bay Bird Observatory writes:

Life at a south-eastern Bird Observatory is full of surprises throughout the year. Late winter cold snaps on the continent can start the year off with a bang as wildfowl and thrushes burst into the recording area, whilst counts of almost 150 Woodcock in a morning have occurred in recent times. The spring sees thousands of northbound finches flying over, thermalling raptors, and Whimbrels passing through en masse, whilst typically scarce overshoots such as Kentish Plover, Temminck’s Stint, and Serin are reasonably regular. In 2016 an epic Lithuanian Blue Tit recovery set new records in the spring (see Demog Blog story), whilst both Long-billed Dowitcher and Common Crane treated the visiting young Next Generation Birders.



This is what a Lithuanian Blue Tit looks like - photo by Becky Johnson

Summers are typified by the (now increasingly rare in the UK) sound of the Turtle Dove, breeding waders, and of course, the Nest Record Scheme. Co-ordinated efforts to monitor, ring, and assess our breeding populations take priority whilst our recently started Retrapping Adults for Survival (RAS) projects on House Sparrow and Collared Dove are already bearing their first fruits. Bee-eater, Quail, and Honey Buzzard are all possible this time of year but highlights are just as likely to be non-avian being a truly fantastic site for Lepidoptera and Odonata records.

As the summer draws to an end things start to heat up. Autumn is traditionally our busiest time of the year avian-wise. Sandwich Bay Bird Observatory has a long history of ringing unusually large numbers of House Martin, Common Sandpiper, and Lesser Whitethroat during this time, as well as being one of the premier sites in the UK for Pallas’s Warbler. Just under 10,000 birds were eventually ringed in 2016, most of which were caught in autumn. In a typical year 7-8,000 birds may be ringed though a recent high of 11,000 occurred in 2015. Looking back at the most recent autumn, numbers such as 1,350 Blackcaps, 1,200 Chiffchaffs, 585 Robins, and 640 Blackbirds make impressive reading.

Tallies can vary from year to year as weather dictates what arrives and what carries on towards France. Meadow Pipits are usually ringed in excellent numbers, species such as Firecrest, Nightingale, Ring Ouzels, and Redstart frequently show well, as well as being one of the best sites to get to grips with continental Coal Tits. In recent year’s rarities such as Red-flanked Bluetail, Great Grey Shrike, Icterine Warbler, Wryneck, and of course, double-figures of Yellow-browed Warblers have found their way into our mist-nets.



Icterine Warbler - photo by SBBOT

The real highlights though come in the form of some very note-worthy foreign controls including a series of Robin recoveries all arriving in a fantastic three week period in October. One bird from Usquert, Netherlands moved 427 km in 16 days, another 545 km from Helgoland, Germany also in 16 days, but one record stood out from the others, the cream of the crop was an individual that was ringed at Kovda, Kandalakshskiy District, Murmansk Oblast, in RUSSIA! A movement of 2,460 km and believed to be the longest distance and furthest east Robin recovery in BTO history. Further interesting records included a good run of Common Redpolls (one being a Danish ringed bird, a movement of 814 km) as well as another Eastern Lesser Whitethroat (S.c.blythi) confirmed by DNA analysis (below).



Lesser Whitethroat - photo by SBBOT

If you would like to visit or ring, then stop by the Field Centre for more details. The home of Sandwich Bay Bird Observatory offers modern, comfortable, self-catering accommodation, allowing you to be on hand for early morning bird ringing, late night moth trapping, club events or just more time to explore the local area. We offer a self-contained flat, twin, family, and single rooms. All guests have use of shared shower facilities, kitchen, dining room and lounge. What’s more, you just might get a snapshot of all the additional behind the scenes crucial work ongoing at Bird Observatories across the UK. Be it the full digitisation of historic data for Birdtrack, Butterfly Monitoring Scheme Transects, the Kent Moth Group, RSPB Wildlife Explorers and Phoenix clubs, and more.

For more information see our website.

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.

RAS double century

The Retrapping Adults for Survival (RAS) scheme was established in 1998 and uses bird ringing to monitor survival rates of a range of bird species. Coverage is particularly aimed at species which, due to their behaviour or the habitats they occupy, are not often caught by standard mist netting activities in woodland, wetland or scrub, such as Swallows, Dippers, Pied Flycatchers and many seabirds and raptors.

With the RAS season already underway for many species, registrations for new projects have been arriving thick and fast here at BTO HQ. At the time of writing, a fantastic 19 new projects, covering 16 species, have registered to start in 2015. A milestone was reached a few days ago with the registration of a new Tree Sparrow project in Cleveland which became the 200^th active RAS project.

Tree Sparrows are a species of high conservation concern due to a spectacular crash in numbers of breeding birds between the late 1970s and early 1990s. Whilst BBS data suggest a significant increase in numbers since 1994, maps from the latest Bird Atlas show breeding Tree Sparrows as being absent from much of the south and west of the country and also declining in abundance south of the Midlands.

Maps reproduced from Bird Atlas 2007–11, which is a joint project between, BTO, BirdWatch Ireland and the Scottish Ornithologists’ Club. Map reproduced with permission from the British Trust for Ornithology.

Tree Sparrow is one of the RAS target species identified in the demographic targeting strategy. Currently, only one project, a study in Durham, has been running for long enough to contribute to the RAS survival trend, and the results suggest that, on average, about half of all adult Tree Sparrows breeding in 2015 will still be alive in 2016. But is this the case at other sites across Britain & Ireland? With two new RAS projects starting in 2015, the total number of active studies will increase to six, giving a much better idea of the national picture.

One project currently contributes to the national survival rate trend for Tree Sparrow (solid line), which shows that around half of the birds alive in one year currently survive to the next; the quality of the trend is considered to be 'uncertain' as the errors (dotted lines around the solid line) are relatively large – addition of more projects will help to reduce the size of these errors. 

There have been recent increases in the number of projects for Mute Swan (now three active projects), Starling (now 10 active and five historical projects), Swift (now three active and two historical projects) and House Sparrow (now 21 active and 12 historical projects) which is fantastic. It would also be beneficial to have a few more projects on species such as Tawny Owl, Barn Owl and House Martin to allow us to produce more accurate trends for these species.

It is rare for all active projects to run in a given year and there are always a few projects that have to end for one reason or another. That said, with more projects still registering for 2015, it would represent an incredible effort if the number that submit data this year hits the 200 mark for the first time.

A massive thank you to all current, past and soon-to-be RAS ringers for their tremendous efforts. Keep an eye on the website for the 2014 results which will be published soon.

Sand Martin Shenanigans

Richard du Feu is currently taking part in a Retrapping Adults for Survival (RAS) study on Sand Martins at Whittington, Lancashire. Little did he expect that one of the breeding males L334091, ringed at the site on 08/07/2010, would be later re-caught by ringers, whilst wintering in Africa, at Parc National du Djoudj, Senegal on 13/12/2010 (4363km in 158 days).

Amazingly he retrapped this same bird, on Tuesday night, at the original breeding site, just 15 metres from where he ringed it last year.


Richard also had two French ringed Sand Martins so far this year and two British controls with several birds moving up to 15km along the river lune. Higher than average numbers of adults have returned to many colonies this summer so the prospects for a productive breeding season are looking good.

Thanks to Richard for letting us know and to Jez Blackburn for the photo.