Ringing and nest recording; the dream 'info team'

Monitoring nests for the BTO Nest Record Scheme gives us a really good estimate of the number of fledglings produced from the average nest each year, but this is obviously only the first part of the story - for breeding success to have an impact on the future population size, these young birds have to make it through autumn and winter to the following spring. By fitting rings to chicks in the nest and recapturing them as free-flying individuals, volunteers are able to follow their progress over this period. Calculating post-fledging survival rates from these data is actually very challenging as many young will move from the site in which they were raised and settle to breed in areas where there is a lower chance of them being re-encountered. However, those that are observed subsequently provide vital information on dispersal and settlement, key processes by which birds are able to change their ranges over time in response to changing climate and habitat quality.   

Brood of Blue Tit chicks. Photo by Mainwaring

Another big advantage of ringing nestlings is that the exact age of re-encountered individuals is known. Most songbirds have replaced all their juvenile feathers by the end of their first breeding season and, from this point onwards, it is impossible to determine how old they are. As age can have significant impacts on behaviour and breeding success, precise information is very valuable. Another certainty established by ringing chicks is the breeding population from which they originated, allowing researchers to determine which areas are net producers of young birds, and which may be population sinks.

Dave Leech studying Reed Warbler nests. Photo taken by Lee Barber

The totals presented in the Ringing Report show that in 2015 alone, over 167,000 nestlings (termed 'pulli') were ringed across Britain and Ireland. In almost all cases, the chicks ringed in each brood would have belonged to the same species, but there are exceptions, as Ian Wrisdale explains:

On a relatively large site of former gravel pits, I run nest box monitoring scheme, a Constant Effort Site (CES) and conduct autumn/winter ringing between October and December. To avoid the possibility of winter flooding, the ringing activities move from the reedbed of the CES, to an area of scrub/young woodland on the opposite side of the site for the winter. Due to the site being a Site of Special Scientific Interest (SSSI), all of the ringing activities are in accordance with agreements with Natural England. The agreed purpose of the winter ringing is to catch winter thrushes; however, it usually entails catching many tits. Whilst the outcome of the nest boxes is usually recorded as, “Nest Empty”, the winter ringing serves to confirm this outcome, monitor the movement of the birds around the site and allows some comparison of breeding productivity with post-fledgling survival.


The reedbed and wet willow scrub of the CES. Photo by Ian Wrisdale

During the last two seasons I have had two mixed broods of tits sharing the same nest box. In both cases, the brood comprised several Great Tits and a single Blue Tit. It is usual to assume that a single Blue Tit would struggle to survive with such competition but, in both of these cases, there was no sign of a dead Blue Tit in the nest box and the outcome was recorded as, “Nest Empty”, assuming at least a partial success. The Blue Tit in question this year was ringed on the 28 May, at the same time as the seven Great Tits with which it shared the nest. But its survival was not confirmed until it was recaptured during the first of the winter ringing sessions, on the  02 October 2016. Whilst I was pleased and surprised to be able to confirm its survival, it was a small, possibly female, individual (wing 60mm, mass 9.8g), making its successful competition against the Great Tits seem all the more remarkable.

Winter ringing in woodland scrub. Photo by Ian Wrisdale

It is unlikely that I will be able to catch it during the breeding season, unless I can agree, with Natural England, to conduct some summer ringing sessions at the winter site or catch it on the nest, but it would be interesting to see if it goes on to breed successfully, or will it think it's a Great Tit.

Eds - If you are a ringer and regularly ring resident species at a site during the winter, it would be worth considering if you are able to find and record the nests of these species. Even getting in touch with your local nest recorder could be beneficial. As this post demonstrates, the quality of the data can be dramatically increased.

Fire with red and yellow

It has been an exciting time in the Demography team over the past month, with data and news arriving in earnest. In terms of bird migration, the winds were coming from the east, bringing rare birds with them to our shores, as described in the BTO Bird Migration Blog.

Yellow-browed Warbler featured very highly last month, with another bumper year, see BirdTrack reporting rate graph below. At the beginning of October, Fair Isle Bird Observatory counted 72 and Cape Clear Bird Observatory managed to ring its 60th Yellow-brow of the autumn. West Cornwall Ringing Group have also been doing very well for this species with 56 ringed so far this autumn.

The Online Ringing and Nest Recording Report shows recoveries for Yellow-browed Warbler are few and far between, with exchanges only occurring between Britain and Ireland and the Channel Islands, Norway and the Netherlands. This year however, we have heard that one was caught at Brownstown Head, Ireland wearing a Russian ring! Hopefully we will get all the data soon.



Yellow-browed Warbler, taken by Lee Barber

Another autumn visitor is the Firecrest and we have just received the ringing details of a Firecrest recaptured a few years ago by the Teifi Ringing Group wearing a Belgium ring. This bird had travelled 566 km in two months and 10 days.

Whilst migration of small passerines is starting to reduce, thoughts now move to the influx of winter birds such as thrushes and Waxwings. Redwing in particular have been arriving in large numbers, and some ringers are getting close to 1,000 birds ringed this autumn. We will have to wait and see if our 2016 ringing total for Redwing beats the 11,743 ringed in 2015, but it is looking good so far.

DemOn in DM out

Dorian Moss is retiring from the BTO as Ringing Database Officer today.


It is best to smile when you are at work!

He joined the team in May 2008, particularly so as to draw up the specifications for the new ringing database, and was one of the team bringing this to fruition in 2014. He has been one of the five staff managing ringing data and recoveries for the past 8 years. From 2008 to 2014 he had the main responsibility for final checks on recoveries and moving them to the permanent database and sending them out to ringers and finders. Then in June 2014 the new database went live, and Dorian started to concentrate on managing the vast resource of ringing data input by our volunteer John Bonell.

Dorian in his favourite habitat, the ringing schedules store at The Nunnery

Since we have been using the new database, Dorian has taken a special interest in checking out new ringing sites, making sure that the grid references and coordinates are correct by checking on maps and Google Earth. Ringers may well have received enquiries from him when things didn’t look correct.

We wish him well in his retirement and look forward to seeing him out collecting valuable ringing data in due course, now he has all this time on his hands. However he is a glutton for punishment, and he has agreed to take over the (unpaid) role of EURING Databank Manager from Chris du Feu in 2017. So he will keep his brain working and we will still have contact with him.

A splash of gold

Back in March BTO Ringer Roy Pearson ringed a Goldcrest in his garden and has recently received some exciting news about his Goldcrest.

At 09:00 on 25/03/2016, I ringed a female Goldcrest in my garden in Boston, Lincolnshire. The bird weighed 6.9g.


Female Goldcrest. Photo taken by Anne Carrington-Cotton

This was subsequently caught by a ringer at 08:00 on 02/04/2016 at Griefswalder Oie, Mecklenburg-Vorpommern, Germany.  This is close to the Baltic Sea and the Polish border, a distance of 931 km from where it was ringed (see map below). The duration was an amazing 8 days.

This is all the more remarkable as I ring very few Goldcrests in the Fens and is only the second recovery of this species in nearly fifty years of ringing.  The other recovery was also this year, but on this occasion the distance covered was merely a few hundred metres.

 

Eds write:

 

A ringer is nearly twice as likely to catch a foreign ringed Goldcrest in this country than to have a BTO ringed one found abroad. Around 22% of BTO-ringed foreign recoveries are found in The Netherlands followed by France (19%), then Belgium (16%). The bird in Roy's report is also one of the most-travelled BTO-ringed Goldcrests.

 

In a month's time we should reach the peak in Goldcrest sightings, as shown by BirdTrack (below); the sightings are currently following a similar reporting rate to last year (however there was an unusually high number of birds reported last October as previously posted). So if you see a ringed Goldcrest and are up for a challenge, have a go at reading the ring (usually 6 digits). It might have words like 'Norway or 'Sweden' as well.

 

Who ringed the Plover?

The BTO Online Reports map for Ringed Plover shows a very broad distribution of recoveries of birds that visited Britain or Ireland at some stage during the year. By looking in detail at the time of year they were ringed and subsequently found, we can start to tease apart what is going on. Thanks to the Gulf stream making our shores relatively warmer than those further north, thousands of small waders winter here and some birds that have bred here move south to winter in France, Spain and even Africa.

Ringed Plover recoveries. Purple: ringed in Britain & Ireland, Orange: found in Britain & Ireland

At this time of year there will be a mix of birds moving south and birds that have just arrived. Telling the difference between these is where ringing comes into its own. As we have posted previously, Lee Collins spends hours throughout the year looking at birds' legs at Dawlish Warren. One of his recent finds included this colour-ringed Ringed Plover (below).

Ringed Plover - photo by Lee Collins

After a little searching it became clear that this bird was ringed 42 days previously at Dufour River, Byulot Island, Canada! This is currently the second report on our system of a Ringed Plover from Canada. This bird was ringed while 'he' had an active nest with eggs (which hatched two days later), so assuming they were not predated, he must have made a very quick trip to Dawlish Warren from Canada. He was one of 73 birds fitted with a geolocator. When these birds arrive back in Canada, and Don-Jean Leandri-Breton resumes his nest study, hopefully the retrieved geolocators will provide information on when and where these birds have been since the geolocator was added.

To get the full effect of how remote the ringing location is, just zoom out of the map below.

Photo taken by Don-Jean Léandri-Breton

Photo taken by Don-Jean Léandri-Breton

For more information see the Dawlish Warren blog.