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

Bumper Barn Owl breeding season

Barn Owls are one of our most iconic and recognisable birds. Over the past couple of years this species has struggled due to severe weather events, with last year being particularly difficult as reported here and here. It is estimated by Colin Shawyer of the Barn Owl Conservation Network (BOCN) that only one third of the British Barn Owl population attempted to breed in 2013.

Successful Barn Owl breeding seasons are dependent both on favourable weather conditions and food availability. The primary food item for Barn Owls is the Field Vole which demonstrates cyclical population trends. Reports coming in to us here at the BTO suggest that 2014 is a good vole year and as a result, may turn out to be the best Barn Owl breeding season since 2007. Early estimates from the BOCN suggest that an average of 33% of pairs have had second broods this year, although in some areas, this figure could be as high as 65%. Average brood size (first and second broods) is also high although the recent spell of wet and colder weather may have impacted on fledging success for some broods.

Whilst we have not yet had all of the ringing data for 2014, the totals are already up on last year. For example, in 2013, only 20 Barn Owls were ringed in May and 183 were ringed in June. This year to date, we have received the details of 428 Barn Owls ringed in May and 1,814 ringed in June!

Adult Barn Owl (photograph by Ruth Walker)

The following stories have been sent to us by some of our Barn Owl ringers and nest recorders:

Chris Griffiths of the Montgomeryshire Barn Owl Groups writes:

Our record year was in 2005 when we had 73 pairs producing 249 pulli. Following the two hard winters of 2010 and 2011, then deep snow in March 2013, we slumped last year to 14 breeding pairs producing 49 pulli. This year Montgomeryshire had 37 pairs producing 149 pulli. Interestingly a third of this year’s birds have been recorded at “new sites”, either newly erected boxes, or boxes that have been up a while but have never been used. Many of the “traditional” sites remain empty. For the first time since I have been involved with MBOG, thanks to ringing, I can confirm that we have also had a few second broods this year.

One unusual instance this season was that I found a ringed female bird in a box with four young on 12/6/14. This female was ringed by me in 2013 and counting back she must have started breeding at eight months of age.  On 21/7/14 I found her again 4.4 km away on a second brood of six eggs and one freshly hatched chick. A quick chat with Colin Shawyer revealed she must have left her first brood nine days after I had ringed that clutch. Apparently, this is not unusual but the distance of 4.4 km is! She almost certainly took up with another male, probably on the edge of his “territory” and left the first male to bring up the kids alone (this is something BOCN were beginning to suspect at a number of sites in years where double brooding occurs).  The good news is that the first brood of four and the second brood (which had dwindled to five when I ringed them) all fledged successfully. On returning to the first site at the end of August, we found “superdad” (who was caught and ringed in a nearby box earlier in the season) in the box with another male that I had ringed as a pulli last year 11 km away.

Barn Owl chick (photograph by Ruth Walker)

Alan Ball writes:

Barn Owls have done exceptionally well in Lincolnshire this year. Bob Sheppard and I have monitored nearly 400 nesting attempts from at least 340 pairs and have ringed over 1,200 chicks. We have not rechecked every site, so will have missed many second broods as probably around a third will have attempted to breed again. Now, in mid-October, some of the late second broods are struggling as weather and food availability has an effect, but we are still finding a few healthy broods. Of particular note this year was one fen just south of Bourne, which had six pairs, raising four broods of seven and two of five. It's amazing that one fen of approximately eight square kilometres could furnish enough food for 12 adults and 38 young. Prey encountered in nest-boxes suggests that there has been an abundance of field mice as well as voles this year.

As well as Barn Owls, other species have taken advantage of the abundance of prey and Bob and I have also ringed 449 Kestrel chicks out of 150 pairs monitored, 188 Little Owl chicks from 80 pairs and 120 Tawny Owl chicks. I am now part-way through the daunting task of completing all the Nest Record Cards to record the 2,500 birds of prey handled this year.

Peter Wilkinson sent us this wonderful photograph (taken by Chris Chatfield) of five Barn Owl chicks sitting on their box. 

Geoff & Jean Sheppard, who carry out a RAS project on Barn Owls, write:

Our study area is in the SW corner of Scotland where we monitor about 80 sites, the majority of which have a nest box. Although there was not a large increase in occupied sites, few had single birds and most were successful with notably larger brood sizes. The number of pulli ringed almost doubled but the number is still well below the usual 150+ achieved in the previous decade. For the first time in many years, a pair at one site had two broods, a six and a four. Interestingly, in certain areas, many sites remained unoccupied suggesting that vole numbers had not increased uniformly and this may be due to the fragmented habitat in the study area. This year, in three occupied sites the pulli failed to survive due to death of one or both adults. In one case, this was due to Jackdaws completely blocking the nest box entrance and trapping the female with her chicks at the back. On a lighter note, a pair in a derelict cottage forsook their usual loft space and raised their brood on the corner of an old bunk bed!

Colin Shawyer writes:

Perhaps my most well studied Species Recovery Areas is that in the Peterborough District. This work was initiated in the early 1990s and, as a result of concerted conservation effort, has seen an increase in the breeding population from six breeding pairs in 1992 to 60 pairs today. The 80 artificial nest sites which have been installed here, largely on a 1.5 km grid matrix, have been monitored annually during the last 20 years and the study area now represents the highest density of breeding barn owls in the UK. This year has seen 75 of the potential sites available in the study area, occupied by 60 breeding pairs with about 70% of these double brooding. The average first brood size (close to fledging) this year is slightly greater than four with ringed broods of six, seven and occasionally eight at about 50% of sites. Second broods are still being ringed but as is normally the case, although clutch sizes are generally higher than in firsts, brood depletion is almost always greater with some having gone from seven chicks to fledge one, two and three. The average second brood size at ringing is, nevertheless likely to remain above three. At a few sites, fledging success over both broods has exceeded ten!

Nice weather for nesting

Having put up with dampened breeding success in 2012 and a chilled start to the season in 2013, how are breeding birds faring this year following the relatively fine winter and spring? This timely question from BBC Springwatch prompted the Demog team to appeal to BTO nest recorders and ringers for any mid-season information they could pull together. True to form, an amazing 112 responses were received from recorders in just two days, which we've summarised below for seven representative species.

Barn Owl

Last breeding season was a very poor one for Barn Owl because of the adverse spring weather and lack of voles. Many birds did not even attempt to nest. Preliminary reports for 2014 from the nine recorders who contacted us about Barn Owl are much more positive, however: high site occupancy rates, laying 2-3 weeks ahead of schedule in places, large clutch sizes and large broods. There has also been some exceptionally early laying: Peter Rose in Northumberland found a Barn Owl pair on eggs in late February. This season's promising start has no doubt been aided by mild conditions but, as Colin Shawyer anticipated in his forecast for the season, the most important feature has been the incredibly high vole numbers, confirmed by the large food caches being reported in boxes.

A Barn Owl box with young looking out. Barn Owl box occupancy rates are reported to be back up this year after many birds didn't breed in 2013. Photo by Dave Short

Kestrel

Reports form BTO nest recorders in Lancashire, Cheshire and Lincolnshire suggest that laying is 1-2 weeks earlier than average in 2014 and up to three weeks earlier than last year. As with Barn Owls, this may reflect a plentiful food supply in addition to the warm temperatures. Clutch and brood sizes seem to be above average, again due to the large amount of mammalian prey. The reported early start will give young more time to build up strength and learn to hunt before winter, which may increase survival.

A brood of five Kestrel chicks in a box inspected by Essex nest recorder Steve Baines last week. Photo by Steve Baines

Peregrine

Reports from nest recorders in southwest England and Shropshire suggest that laying dates are not significantly different from the average. In contrast to the vole-dependent raptors like Kestrel and Barn Owl, Peregrines seem to be having an average to poor year in terms of numbers of breeding pairs and brood sizes. The wet weather in late spring may have reduced female condition, resulting in suspension of breeding and/or small clutches. Wet summers can adversely affect Peregrines by reducing prey activity levels and therefore hunting efficiency.

Swallow

Reports from 25 recorders suggest that laying is occurring a week or so earlier than last year, which is similar timing to previous warm years, such as 2011, and within typical levels of annual variation. As with Reed Warblers, the odd early attempt was noted: John Lloyd in Carmarthernshire recorded his first April eggs in 40 years of monitoring. A reasonably early start bodes well for repeat broods this year, so long as there isn't prolonged heavy rain, which can prevent birds hunting for airbourne insects. Large clutch sizes have also been reported this season.

Reed Warbler

This long-distance migrant rarely gets going before May - there are only 11 Reed Warbler nest records with April laying dates out of an NRS dataset of 10,000 - but this season several nests with eggs in April have been monitored by recorders in south Wales, Avon and Norfolk. However, it appears that these few early nesting attempts, enabled by warm weather stimulating good, early reed growth, were followed by a delay of 1-2 weeks before the main body of birds began laying at the normal time. This may have been due to delays on passage caused by cold, wet weather in southern France and Spain. BirdTrack data show that the timing of arrival in the UK was similar to recent years, from the second week of April onwards.

The peak breeding period for Reed Warbler, a long-distance migrant, begins in mid-May and finishes at the end of July. A pair will have 1-2 broods a year. Photo by John Harding

Blue Tit

Last season was one of the latest for nesting Blue Tit since the mid-1960s. From early reports this season, however, it appears this is one of the earliest on record, with laying 2-3 weeks earlier than normal. Andy Turner in Oxfordshire recorded a mean first egg date of 9th April, almost a month earlier than 2013 (6th May). Clutch sizes appear to have been average to below average - this could be down to high adult abundance, and therefore competition, following the good survival prospects over the 2013/14 warm winter. However, warmer springs also tend to be poor for productivity as, although birds advance their laying, caterpillars advance emergence by a greater amount, therefore reducing the synchrony between demand from chicks and availability of insect food. Moreover, the recent wet weather appears to have had a negative impact on chick survival - wet summers in general are problematic as they wash much of the insect food from the canopy.

Long-tailed Tit

Despite the warm weather in February and March, reported laying dates this season are close to the average, if towards the early end, with most clutches being built between late March and mid April. The wet weather in late winter may have delayed breeding somewhat if it meant that females struggled to find food and began the season in poor condition. Preliminary reports from ringers suggest that numbers of fledglings are much higher this season compared to 2013, which was particularly poor for Long-tailed Tit, owing to the very low temperatures in late winter and early spring. Warm, dry weather benefits fledgling survival as small birds can chill easily when wet.

Long-tailed Tit is one of our earliest breeders, typically laying from late March until early May. They only have one brood per year, although may relay if the first fails. Photo by Elspeth Rowe

Many thanks indeed to

Alan Ball, Bob Sheppard & Keith Bowden, James Anderson, Steve Baines, Tim Ball, Batty and Bateman, Phil Belman, BIAZA Nest Recording Project, Derek & Mary Bickerton, Rorger Bird, Bristol Naturalists Society, Paul Cammack, Steve Carter, Barry Caudwell, Centre for Ecology and Hydrology, Charnwood Ringing Group, Michael Colquhoun, Brenda Cook, Simon Cox, Ruth Croger, Crombie Country Park, Cwm Clydach RSPB Reserve, Robert Danson, Chris Dee, Richard Denyer, Derek Holman, Karl Ivens and Andy Glover, Thomas Dewdney, Ed Drewitt, David Dutton, East Dales Ringing Group, Chris Evans, Mark Fletcher, Jeremy Gates, Adrian George, Steve Gray, Philip Hanmer, David Harazny, Ian Hartley, John High, Kenneth Hindmarch, Peter Holmes, Mike Hounsome, Michael Hunt, Cynthia Hyde, Iain Inglis, Peter Johnson, Kelvin Jones, Tom Kittle, Lancaster & District Birdwatching Society, John Lawton Roberts, Alan Levitt, Jerry Lewis, John Lloyd, Garth Lowe, John Mark, Frank Mawby, Philip May, Kevin May, Michael McDowall, David Mckee, Merseyside Ringing Group, Minsmere RSPB Reserve, Colin Moody, Gerald Murphy, Mervyn Needham, Ian Nicholson, North Cotswold OS, North-west Norfolk Ringing Group, NT Farne Islands, Parc Natur Penglais Support Group, Keith Parkes, Pinley Abbey Nature Reserve, Pitsford Reservoir, Andrew Ramsay, Derek Robertson, Paul Robinson, Peter Rose, Paul Roughley, RSPB Fowlmere, RSPB Grange Farm, Salisbury Plain MOD Conservation Group, Malcolm Samuels, Robin Scott, Keith Seaton, Dave Short, Shropshire Peregrine Group, Doug Simpson, Judith Smith, Sorby Breck Ringing Group, South Derbyshire (Souder) Ringing Group, South Devon Nestbox Group, South East Cheshire Ornithological Society, South West Lancashire Ringing Group, South West Peregrine Group, Derek Spooner, Ian Standivan, Suffolk Community Barn Owl Project, Tay Ringing Group, Simon Taylor, Roger Taylor, John Thompson, Treswell Wood IPM Group, Andy Turner, Stephanie Tyler, David Warden, Barrie Watson, Waveney Ringing Group, Denise Wawman, West Midland Bird Club, West Midland Bird Club Boddenham, Williams and Tabor, Wirral Barn Owl Trust, Ian Wrisdale

Spring weather bad news for Barn Owls

Over the summer we've been hearing some pretty depressing stories of how badly Barn Owls seem to be doing this year. The poor spring weather appears to have been bad for small rodents, the staple diet of most Barn Owls. Birds in poor condition may choose to skip breeding for the year and others starting breeding may abandon attempts part way through due to lack of food.

Food shortages can severely limit breeding performance
(Jill Pakenham)

Below are a few extracts from emails and Forum posts we've received, giving a flavour of the season from around the country.

Lincolnshire (Alan Ball and Bob Sheppard)

"Only about 60 pairs have been found breeding so far, where we would have normally expected around 200 pairs by now. Only 55 chicks have been ringed compared with 160 by this time last year. Several pairs are just starting to nest, so there's hope that things may improve, though birds remain absent from many traditional sites

Kestrels are also down with nearly 150 chicks ringed against nearly 200 last year. Tawny Owl chicks numbered only a third of last years numbers, but Little Owl site occupancy was good with our best year ever of 70 pairs."

North West Norfolk (Phil Littler and John Middleton)

"I've just got in from checking 30+ boxes, and have got just three on eggs. Three sites had dead owls in or under the boxes, and just five sites held any Owls at all. A thoroughly depressing day. I thought it would be bad when my Tawny Owl totals showed a 75% drop on last year, but not as bad as this."

"Well now I have checked over 200 sites and only 34 pairs are breeding, 14 sites have pairs that are not yet breeding and 25 sites had single adults. So far I have only ringed 34 chicks although I do have to re visit 16 sites because chicks were too small or the female was incubating eggs. I still have a number of sites still to check but don’t expect it will get better. Can’t see the Group this year ringing anything like the 391 chicks we ringed in 2012!"

Wiltshire (Alison Rymell)

"I checked 11 boxes in the Deverill Valley in mid-June: none had either eggs or young. Only one had a pair of owls and one had a single owl. Another had a dead owl [long dead]. Four had Stock Doves, three with eggs. Of the 11 boxes, six normally have successful broods. Last year four of the six lost their first broods, three laid a second clutch and reared the young successfully."

Cornwall (Mark Grantham)

"We still haven't done all our boxes, but so far the season seems to be 5-6 weeks later than previous years:

• 7 sites occupied last year but not this year (and one unoccupied for the first time in 17 years!)
• 3 sites occupied but not breeding
• 6 sites with chicks, but all small broods
• 3 failed at the egg stage
• 7 not occupied this year or last year
• 2 sites occupied but outcome still unknown"

One of the non-breeding pairs from a Cornish nest box (Mark Grantham)

Tawny having a tough time

The nests of Barn and Tawny Owl have been recorded in Lincolnshire and Nottinghamshire intensively since the mid 1980s. This has provided a wealth of information, which is used to look at many aspects of breeding success.

Adult Tawny Owl by Carol Greig

Adrian Blackburn and Jim Lennon, along with help from other ringers, checked 82 Tawny Owl nest boxes on 21-24 April 2013 in East Lincolnshire, and recorded an occupancy rate of just 17% (14 boxes). Squirrel, Jackdaw, Stock Dove and Great Tit were also recorded. In total in 2013, just 17 chicks were ringed from seven broods; half of these were provided by two surprisingly large broods of four chicks, with and one other containing three young while the remainder were the rest consisted of single nestlings or pairs of owlets. This is much lower than the average number of 36 ringed young recorded over the period 1996-2012 and far below the highest annual total ever, an impressive 62 chicks ringed in 2005.

There were still two nests with eggs on the last visit could potentially produce more chicks but are very unlikely too at this stage; the other five had failed either during incubation or soon after the chicks had hatched.  We posted previously about the hard time Barn Owls were having due to the cold spring, so finding that Tawny Owls were also having a hard time was not a great surprise.

Some reasonably healthy Tawny Owl chicks by Carol Greig

There is evidence of a lack of prey from the boxes with fewer voles and mice being found, these being replaced with more unusual items, including the hind leg of a hare, a Carrion Crow’s head and a few shrews. It is notable that the boxes in ‘prime’ deciduous woodland habitat, which usually produce the majority of offspring, fared worst, with those in suburban gardens achieving a much higher output. Could it be that small mammal populations in woods have become depleted during months of cold weather and poor vegetation growth, while garden rodent populations thrive on the artificial food provided for birds?  The situation is probably not helped by the breeding season for song birds being delayed by several weeks, potentially reducing the availability of young birds as prey.

Thanks to Adrian Blackburn and Jim Lennon for letting us know.

Cold spring hits Barn Owls

The past couple of winters have seen some severe cold weather, making life difficult for many bird species. The Barn Owl is one species that can be heavily affected, and we have seen reporting rates of dead ringed birds rise. This usually happens earlier in the year but this year the reporting rate for late March has shown an exceptional increase, just when these birds are supposed to be starting to breed!

Barn Owl - Les Foster

At this time of year we normally receive reports of birds that have been hit by vehicles on the roads but this year a high proportion have been found emaciated close to peoples houses and allotments. This is a sure sign that things are not well in the countryside and food resources are very low.

The graph below shows just how extraordinary late March 2013 has been. The figure is sure to rise for early April this year but we hope it doesn't compare to late March.

Deep snow, wind and flooding has hindered the ability for Barn Owls to find food. This will also be having an effect on other birds of prey that feed on rodents and small mammals.

Kestrel vs Barn Owl - a nesting tale

The Barn Owl is by far the most commonly nest recorded owl species in the UK and Ireland (1,823 nest records in 2011, compared with 476 Tawny Owl and 143 Little Owl). The Barn Owl has benefited from all the hard work volunteers have put into increasing the number of possible nesting sites through Schedule 1 licenced nest box schemes all over the country. With the increase in nesting sites, Jackdaw, Stock Dove and Kestrel also nest in these boxes.

We have just heard from Adrian Blackburn concerning a Barn Owl box that has been used by Barn Owls for the last 3 years. When this box was checked on 05/06/2012 it had 5 white Barn Owl eggs and also 4 Kestrel eggs (below) that were being incubated by a female Barn Owl. This would normally mean that the owl had evicted the female Kestrel and laid her own. However when the next check was done, there were 5 tiny Barn Owl chicks and one tiny Kestrel chick, two warm Kestrel eggs and one addled Kestrel egg. The next box check had 3 Barn Owl chicks and the unhatched Kestrel egg.

As owls usually incubate from when the frst egg is laid, the owl chicks will hatch about a day apart, giving the earlier hatching chicks a better chance of survival during lean times. This is done by eating their siblings and in this case the smaller Kestrel chicks would probably be on the menu.

Adrian and his team have had dual occupation in their boxes before i.e. Barn Owl / Kestrel and Barn Owl / Stock Dove but never with a Barn Owl incubating the other species eggs and hatching them out!

Thanks to Jill Pakenham for the Barn Owl picture and Jim Lennon for the egg picture.

White wonderland

As you may guess, we receive quite a lot of reports in the Demography team regarding swans. So far this month, we've had 26 reports of Mute Swans, 10 of those were reported alive and 9 were ring-read sightings, one  was caught in netting and released.


Of the 16 swans that were reported dead, the stated cause of death was: hit by a car; flew into overhead wires; sick; or oiled. We have also received a remarkable report of one swan that lived for 20 years and we got its whole life history (it was a long report), who it was paired with and what happened to them. This bird managed to raise quite a few cygnets in its time, and even survived being shot in the head twice, but unfortunately it didn't survive the third shooting.


Last year we received a lot of reports regarding the other white bird, the Barn Owl, but this year we have had relatively few. Of the 12 reports received so far this month, seven of them had been found dead (one with its head down a rabbit burrow) and four were hit by vehicles. The last one was reported by a bird of prey centre who report that they are increasingly receiving Barn Owls which have been killed by Buzzards. I'm not sure how common this is or if it is just restricted to the Fife area of Scotland. We'll have to keep an eye on this.

Thanks to Edmund Fellowes for the Mute Swan picture and Neil Calbrade for the Barn Owl.

October oddities and November notables

Grampian Ringing Group definitely got the distance prize for October with a Sandwich Tern turning up in Liberia, West Africa (5679km in 488 days). This chick was ringed at Sands of Forvie Nature Reserve, Aberdeenshire last year and was caught by children playing on the beach in Robertsport but unfortunately died.

We also received 8 reports of Lesser Black-backed Gull wintering in Portugal and all but one were live sightings. Mute Swans were also very evident with lots of sightings but some hitting overhead power cables and one or two in poor condition. Unusually we didn't get many reports of Barn Owls in poor condition but we did get 12 reports of car victims. All of the ones that died were ringed as chicks this year. One bird, strangely, was seen flying straight into a wall and then a parked car before being rescued and taken into care.


There was also a nice Blackcap report "found and released" on 25th October in Tizi-Ouzou, Algiers, Algeria that was ringed near Sleaford, Lincolnshire in May this year (1839km in 174 days). Another notable passerine was a Chiffchaff ringed in Northumberland in August and was found dead after connecting with a vehicle in Candresse, France in October (1257km in 37 days!)

All the above recoveries have been processed and found in either October or November. We are still getting reports of birds found in November so this is not an exhaustive list. Thanks to Dawn Balmer for the photo.

Owl Action on the Nunnery Reserve

During the winter, Paul Taylor and the Nunnery Fisheries team have been hard at work making and erecting nesting boxes, in the hope of attracting owls and Kestrels. This is allows us to complete nest record cards for the Nest Record Scheme and to ring the young birds and possibly their parents too.

Yesterday we completed our first inspection of these boxes, with some interesting results. The first box had a roosting male Barn Owl (we were of course armed with the appropriate schedule 1 licence) and while attempting to sort out the ladder for the second box a Tawny Owl emerged to see what was going on. This bird was sitting on 3 eggs (below) so fingers crossed for 3 lucky ringers when these chicks hatch. Hopefully this nest will follow the progress of the nest the BTO is monitoring.


By this stage we were in a very positive frame of mind but we actually had mixed results. The next Kestrel box had sticks and feathers inside and another owl box was full of sticks, which were probably the work of Jackdaws. Then while also trying to find a Long-tailed Tit nest and failing, the next owl box was empty.

The next two owl boxes produced a Squirrel family and 3 Barn Owls roosting. Hopefully these Barn Owls will start to lay shortly. We were impressed though with the raptor tally for the day, Tawny Owl, Barn Owl, Kestrel fly over and the first Red Kite in Norfolk for Dave Leech.

Black Week for the White Owls

With the number of freezing days now having reached double figures in England and Scotland (read more on our brand new BTO website), the weather is making all the headlines. Similarly, the Ringing Office has received a number of reports from the public of ringed birds affected by the weather; found in gardens, barns, sheds, fields and city centres. Many birds are succumbing to this first wave of severe cold weather and the ringing recoveries reflect this.
For example, this week, we have received 31 reports of dead Barn Owls. In most cases the cold conditions figure as the cause of death. This was a black week for the Barn Owl, a species which probably found it difficult to find any small mammals due to the snow cover and the freezing temperatures.

Other dead birds reported this week which are also likely to be cold weather victims are a Reed Bunting, two Waxwings, a Chaffinch and a Long-tailed Tit.

It will be interesting to find out how many dead birds walkers find washed-up along the coastline this weekend. We will keep you updated on any interesting recoveries!

Thanks to Neil Calbrade for the photo.

Never too late!

The Barn Owl has become one of the most intensively monitored species in the UK. In late summer breeding season would normally be over but this year was a bit unusual as Colin Shawyer recollects...

"In May and early June almost a third of pairs had not attempted to lay and they were unlikely to do so later in the year (due to very low body weights). In mid July gales that lasted three days and nights, prevented adults from hunting and caused entire broods to starve, many of which were only two weeks from fledging.


So far so bleak. But returning to that third of pairs that were on territory but not laying: an interesting observation was noted. At some of those sites the adult females—and even some males—had begun their wing moult, which is a good indication that a pair has ‘given up’ for the season and is unlikely to breed. But at a greater proportion of those nest sites no such moulting was seen. How important these observations turned out to be!

My colleagues and I decided to re-visit many sites in late August and early September and found healthy broods of fours, fives and sixes. The ages of many of these chicks indicated that the eggs had been laid in late June after our earlier visits, when we had weighed the females and surmised they were not to breed. Even some traditionally-used nest sites that were vacant in June contained large and healthy broods.

Had we stuck to our usual plan of only revisiting sites in August where breeding had already been noted, we would have missed a surge of late first-nesting attempts. So it goes to show that there are never two breeding seasons the same for a nest recorder! Overall breeding success in 2010 will not be as quite as bad as we had originally feared."

By Colin Shawyer
BTO - BOMP-Project Development and Monitoring
BOCN - Project Director, UK and Ireland

Follow Colin Shawyer's thoughts on Barn Owl monitoring in his blog or get involved in the Nest Record Scheme next year!

BTO Barn Owl found in Spain

We have just received details from the Spanish Ringing Scheme of a BTO-ringed Barn Owl found dead in northeast Spain. This is an amazing movement, as we have very few records of British-bred Barn Owls going anywhere interesting!

This bird was originally ringed as a nestling in Essex in July 2008. It was then found on 8 November at Pals, in the Girona region of Spain. We're not sure how it died, but it didn't have a head!

We have had a few movements of Barn Owls to Britain from abroad (shown in blue on the map), but fewer reports of birds ringed here and subsequently found abroad (shown in green on the map). Note the rather unusual report from Afghanistan of a bird ringed near an RAF base in Oxfordshire..... Presumably it didn't make it all the way there under its own steam!


View Larger Map

This is a fully functioning Google map, so you can zoom in and out and click on the markers to view the details for each movement.