27 August 2015

How to get up close to a ringer

Gary Clewley writes:

Another year and another Birdfair at Rutland Water has come and gone. The bird ringing demonstration proved to be very popular again with people (and especially families) regularly able to get up close and see the process of ringing first hand. In total, around 175 birds from over 20 species were ringed or recaptured over the course of the weekend. This gave us the opportunity to show people how ringers are able to identify and age birds in the hand as well as explaining why ringing and nest recording are essential for monitoring how and why populations are changing.
Great way to get close and learn about our 'British' birds - Stephen McAvoy

Some species do tend to steal the show however, and the Lesser Whitethroats were particularly popular and also quite relevant to this year’s theme at Birdfair; protecting species in the Eastern Mediterranean. With their easterly migration route, there could be a good chance the Lesser Whitethroats which were ringed could be passing through the Eastern Mediterranean soon.

Lesser Whitethroat taken by Morris Rendall

There was a promising start to the event, when at 8:55 am on the Friday morning, the very first bird in the nets was actually a Sparrowhawk! Unfortunately in this case the bird proved too quick for the ringers and managed to free itself within seconds. So it was an especially pleasant surprise when another adult male Sparrowhawk found its way into the nets on the Sunday morning and even better it already had a ring on. This bird was originally ringed at Rutland Water in 2012 and we now know it is still going strong. A very lucky crowd were able to watch the ringers process the bird.

Adult male Sparrowhawk - Dawn Balmer
Sparrowhawk getting efficiently processed while a lucky crowd watch on - Dawn Balmer
Perhaps the most unexpected bird of the weekend was a House Sparrow (and perhaps a sign of the times since this species has seen a substantial decline in recent years) which is the first ever caught during the Birdfair ringing demonstrations.

Unfortunately, we also had our fair share of unfavourable weather over the weekend so there were times when we were unable to safely catch birds. But nonetheless there were ringers on hand to answer questions and even ‘ring’ some people with the wristbands we had available (if you were ringed you can find out your story here).

The ringing demonstration stand. You can tell where the bird is by the crowd - Stephen McAvoy

It is always a privilege to be able to ring birds and even more so at an event like this. It requires a lot of planning and I would just like to thank all those ringers who volunteered their time to help with the demonstration again for all their hard work, in particular the Rutland Water Ringing Group, as well as everyone who came along to see us.

Eds - There are ringing demonstrations run at various sites across the UK by individual ringers or groups however the BTO, in collaboration with the RSPB, are running their next event on Sunday 30 August at the BTO headquarters from 10 am until 3 pm (catching weather dependent).

07 August 2015

Owl and raptor mid-season update

That annual Barn Owl breeding success is influenced by peaks and troughs in abundance of field voles, the species' main prey item in many areas, is hardly news to Barn Owl recorders. But after seeing some of the lowest levels of nesting activity in memory in 2013, followed by record productivity in 2014, many might be wondering just when they'll next get an 'average' season. Not in 2015 it seems: anecdotal reports so far suggest Barn Owl productivity has been much lower than expected, though other species seem to have followed on better from last year's bumper season.

Poorer than predicted Barn Owl breeding

Back in February, Barn Owl expert Colin Shawyer predicted that, provided spring conditions remained mild, the exceptional number of 2014 fledglings would mean good recruitment of young breeding birds, but also that though egg-laying could be expected at the usual time in late-April/early-May, a decline in vole numbers from their 2014 peak would result in smaller brood sizes and fewer fledglings this year.

Subsequent early visits to Barn Owl nest boxes revealed much less activity than expected. In late May, Colin visited 25 boxes that had contained 16 active nests in March 2014, only to find just eight with signs of adults present and three clutches of eggs. Non-breeding females were found to be underweight, suggesting that, whether caused by recent wet weather affecting foraging or simply the scarcity of voles, birds were late getting into breeding condition.

By mid-June, reports on the NRS Forum were sounding similar. Alan Ball, Bob Sheppard and Keith Bowden, in Lincolnshire, had checked most of their boxes and found four Barn Owl pairs on eggs or chicks. On the same date in 2014, they had been monitoring 200 nests. Frank Mawby, in Cumbria, Peter Wilkinson, in Cambs, and David Garner, in Cambs, were also reporting low breeding occupancy, and an apparent shortage of prey. Bob Danson, a recorder in Lancashire, commented that food larders had disappeared after the very beginning of the season, in contrast to 2014 when piles of six and seven voles were common.

A single Barn Owl chick at 20-25 days. In 2015 there have been many reports of broods sizes dropping to just one or two chicks. Photo by BTO.

In mid to late July, when Barn Owl chicks are often ready for ringing, there were reports of brood sizes of three and four having reduced to just one—Mike McDowall in East Lothian, David Garner in Cambs and Frank Mawby in Cumbria all ringed single chicks. By the time Bob Danson had ringed his latest brood on 3 August, just eight of the 23 nests he had found so far in his 80 boxes had produced chicks, and his ringing total had reached only 18.

Better Barn Owl news has come in from elsewhere: Nigel Lewis at Salisbury Plain observed a good proportion of boxes with clutches of eggs in May and Judith Smith, in Manchester, has ringed several healthy broods of four and five chicks, including some in new boxes. Geoff Myers, in Lancashire, reported that good numbers of both early and later laying Barn Owl pairs had successfully reared broods and that by 24 June he had ringed a brood of six and several broods of five—very advanced compared to elsewhere.

Tawny Owl, Little Owl and Kestrel fortunes

There have been mixed reports for other box-nesting owl and raptor species that tend to be well-monitored by ringers and nest recorders. Alan Ball, Keith Bowden and Bob Sheppard reported that they had ringed just six Tawny Owl chicks in their boxes in Lincolnshire, compared to 130 in the same boxes in 2014. On the other hand, Bob Danson, in Lancashire, encountered 17 nests in 30 boxes—his second best annual total after last year—from which 26 chicks fledged, including four broods of three. Bob noticed that rats made up a higher proportion of prey in his Tawny Owl boxes, along with baby rabbits.

Several recorders have spoken of Little Owls doing well this year, a species that is obviously less dependent on rodent prey. Alan Ball, Keith Bowden and Bob Sheppard monitored 65 nests and ringed 100 chicks, compared to 80 nests and 188 chicks in 2014. Bob Danson's 70 Little Owl boxes saw occupancy increase to 16 pairs in 2014, from 12 in 2014 and 7 in 2013. He recorded 36 fledged young altogether, including a brood of five and two broods of four.

Two recently fledged Kestrels photographed by Wilf Hockney, who accompanied Steve Baines on several of his Kestrel box rounds this year. 

Kestrel reports have also been positive. Steve Baines monitors 20 boxes in Chelmsford, Essex, and 13 had pairs this year, one of his highest occupancy rates, though he noted that clutch sizes were down relative to 2014: clutches of five and four but no sixes, and that the number of chicks fledged overall (36) was slightly lower than 2014. Bob Danson reported a similarly successful season for Kestrels in Lancashire and noted more bird prey in boxes than usual, including a Swallow. In contrast, Alan Ball, Keith Bowden and Bob Sheppard had monitored only 6 nests by mid-June, compared to 150 at the same time in 2014.

Late season comeback?

Although the breeding season has now finished for Tawny Owl and Little Owl—bar perhaps a few exceptionally late nests—there will still be a proportion of Kestrels tending to chicks, and of course there is the question of whether we will see any Barn Owl second broods or late-season nesting attempts in previously empty boxes. As Dave Leech has pointed out in a recent interview for Radio 4, this might happen if non-breeding females have managed to get into breeding condition, although Colin Shawyer has observed that vole numbers appear to remain very low. Either way, good data on the extent of late and repeat broods is essential for assessing Barn Owl productivity, which is why those late-season box checks are so important...

The BTO Nest Record Scheme is one of the ways in which raptor populations are monitored in Britain & Ireland. These results are complemented by periodic single-species surveys and, in Scotland, by the Scottish Raptor Monitoring Scheme.

Many thanks indeed to: Steve Baines, Alan Ball, Keith Bowden, Bob Danson, Wilf Hockney, Nigel Lewis, Frank Mawby, Mike McDowell, Geoff Myers, Colin Shawyer, Bob Sheppard, Judith Smith, Peter Wilkinson

24 July 2015

Found a ringed bird? You are not alone.

With around one million birds ringed every year it is not surprising that we get quite a few phone calls and lots of emails to the ringing team from non-ringers reporting a ringed bird. We get back to each one a few days later with a report on where and when the bird was ringed, and at the same time let the ringer know that one of 'their' birds has been found.

When you add this to all of the recaptures of ringed birds by our ringers through general ringing, especially structured ringing like Constant Effort Sites and Retrapping Adults for Survival, the value of these reports to conservation is huge. There are many aspects of a bird's life that can be investigated by BTO scientists and academics, particularly when results from other BTO surveys, such as the Nest Record Scheme and BBS, are included in the dataset.

Great example of part of a Dunnock nest record by Christopher Rowe

Most of the non-ringers that report ringed birds just get information on the bird they found and are unaware of the magnitude of records that we process. I have looked into the 40,394 reports that have been sent to us so far this summer (since 29 March 2015) from ringers and non-ringers.

Below is a chart showing the percentage of each species that were found by non-ringers and caught by ringers. Blue and Great Tit are of course the top two, followed by other garden birds. Starling is unusually high due to some great Starling colour ringing projects operating from Essex to Montrose. We have had singles of some unusual species so far this summer including Icterine Warbler, Capercaillie, Ruddy Duck and Great Bustard but these are few and far between.

Finding reports sent in to the BTO so far this summer from ringers and non-ringers. Click chart to enlarge.

The chart below is purely those reported by non-ringers. Considering the recent declines in House Sparrow and Starlings, the reports of them are quite high but this is due to the increased conservation effort and colour ringing projects occurring on these species. Fifteen percent for Black-headed Gull isn't surprising for us as a large percentage of the Recoveries Officers' work is processing colour ring sightings of these birds moving between countries and within our country. There is also a large number of people devoted to gulls and ring reading.

Finding reports from this summer from non-ringers only

Our valued BTO ringers not only ring large numbers of birds, to increase our understanding of our bird populations, but they also recapture large numbers of birds that are already ringed. This accounted for 81% of all the birds 'encountered' and reported since 29 March. These are reported to us using a dedicated computer program and thankfully need less processing than non-ringer reports. Out of the non-ringers reports 78% are colour ring sightings - see below for the top 10 circumstances of the report. Discerning the cause of death can be difficult and these records are represented by the red slice on the chart below.

The top 10 circumstances that led to us getting a report this summer.

13 July 2015

Another Hawfinch season over

With the short Hawfinch season over, it was time for Jerry Lewis to reflect on how it had gone this year.

After his best ever season last year, 2015 had been a "bit slow" with just 94 birds ringed, and 34 recaptured from previous years (but good quality data for the RAS). One bird however was particularly noteworthy and was Jerry's second record of an eight year old bird. The previous bird (see here) could not be individually identified so its age could have ranged from a couple of weeks under eight years, to a few days over. On 2nd June, RSPB researcher, Rob Hughes, was watching one of the feeding sites, and saw a male with a white colour ring (which was unusual as orange rings had been used for the previous two years).

Mystery Hawfinch by Rob Hughes

While doing some routine mist netting with Will Kirby and Andy Stanbury, they caught the bird on 3rd June, and Jerry caught him again on 18th. It turned out to be NW31557, first ringed on 27 April 2007 at the same feeding site. In the intervening years, he had been caught three times in April 2009 (at the same site), and once more on 26 May 2013 (at a feeding site some 15 km to the south). His original single colour ring was missing on this last recapture, and he was fitted with a new inscribed colour ring - white inscribed with ZH. There is no way of knowing where he has spent most of the intervening years, but he had obviously not been regularly visiting any of the feeding sites. The latest capture is probably (see below) a new UK longevity record at 8 years, 1 month, 22 days.

Hawfinch by Rob Hughes

08 July 2015

Nest with the best

Over 250 keen NRS participants have attended BTO nest recording courses since veteran recorder and volunteer tutor Tony Davis ran the pilot in 2008. This year, thanks to BTO Scotland and recorders Colin Davison and Gilian Dinsmore, the regular weekend courses in Norfolk and Surrey were joined by a brand new afternoon workshop at Scotland's Big Nature Festival.

Punchbowl pipits

Five weeks ago nine more keen recorders met Tony at the Devil's Punchbowl in Hindhead, Surrey, to spend a weekend increasing their nest finding knowledge. Saturday was spent learning to find warbler and finch nests in gorse at a nearby heath, and looking for Skylark nests at Butser Hill. Then on Sunday the group descended into the Punchbowl itself and soon found what appeared to be two Tree Pipit territories either side of the main path. The next hour was spent practicing watching nesting activity unobtrusively, which for wary Tree Pipits often means at least 50 metres back! One pair turned out to be feeding fledged chicks and an hour spent on the other territory proved inconclusive—at least for the target species. After standing in the same spot for 20 minutes, attendee Colin became aware of a Robin stealthily taking food into a patch of gorse immediately behind him. The bird was watched carefully for two more visits, the 'hotspot' was searched, and a nest found containing four young. Nest number 15 out of 25 found over the whole weekend—plenty for Tony to follow up!

Top: Colin Wilson searches for a Robin nest after watching an adult carrying food. Bottom: Trainee Teifion Thomas rings a brood of Robins from another nest, while ringer Colin Wilson supervises

Scotland's Big Nature Festival

The weekend before the Surrey course, Scotland's Big Nature Festival played host to its first ever nest recording workshop, thanks in part to a local volunteer who couldn't actually be there on the day. Keen for the workshop to include an outdoor demo where people could be shown nests and how recorders safely monitor them, BTO Scotland realised that one of the country's top nest recorders, Colin Davison, lived near the venue. When they contacting him about helping, Colin said that he was working that day but would try to find a few nests in advanceand then promptly located 12!

Top: veteran nest recorder Colin Davison pointing out the location of a Chiffchaff nest. Bottom: Ben Darvill takes people on a bird song tour as part of BTO Scotland's roster of events at the 2015 Big Nature Festival
The workshop was very well attended and began with talks from Mark Wilson (BTO Scotland) on why Scotland needs more nest recorders and another local recorder (and Reed Warbler expert) Gillian Dinsmore on her experiences getting started. Mark and Gillian then announced the outdoor demo and were delighted when 30 keen members of the public stepped forward. Folk were divided into groups and taken on carefully planned tours of Colin's nests, which included some in cover (Blackcap with eggs, Robin with chicks), some on the ground (Skylark and Meadow Pipit, both with eggs), and a Blue Tit nest in an unbelievably narrow crack on the wall of one of the observation hides. It was great to see so many people interested, especially given the pressing need for more recorders in Scotland, and needless to say plenty of NRS starter packs were given out. Both Colin and Gillian have pledged their support for future workshopshopefully Colin will be able to attend the next one!

Interested in going on a nest recording course? Please see here.

A huge thanks to volunteers Tony Davis, Colin Davison and Gillian Dinsmore for making this years' courses/workshops possible, and a huge thanks to BTO Scotland staff Ben Darvill and Mark Wilson, and BTO Thetford staff Mike Toms, Hazel Evans and Debbie Todd. And of course thank you to all the course and workshop attendees!