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