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.

video

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.

Note:
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.