2012 preliminary UK Nest Record Scheme (NRS) results from BTO

Full news report and tables from BTO here

The BTO publishes preliminary results each Autumn to provide an initial assessment on the UK’s bird breeding season prior to the publication of the annual BirdTrends Report the following year. Producing results so soon after the breeding season is only possible thanks to NRS participants’ speedy submission of data.

Record-breaking rainfall

To say it was a wet spring and summer this year is an understatement. UK Met Office rainfall totals for England & Wales in two months were the highest on record, with four times the average falling in April and twice the average falling in June. If the adverse weather affected nesting birds, it also made life difficult for volunteers, resulting in many cancelled field sessions and missed nest visits. However, thanks to the dedication of the nest recorders, over 25,000 records were submitted in time for the preliminary report and 2012 breeding performance figures have been produced for 25 species.

Early breeders advance, late breeders delay

Conditions in February and March were actually warmer and drier than average, and many of the early resident breeders, including tawny owl, song thrush and long-tailed tit, commenced nesting significantly earlier than the five-year average. In contrast, long-distance migrants travelling northwards from their African wintering quarters the following month had to contend with a succession of severe weather systems across Europe and were greeted by cold, wet weather when they finally returned to their breeding grounds. As a result, laying dates of all six species for which preliminary results are produced were significantly delayed relative to the average for the preceding five years. Laying dates of short-distance migrants, blackcap and chiffchaff, which winter in the Mediterranean and therefore return to breed earlier, were no later than average.

Caterpillar-dependent residents struggle

Feedback from lepidopterists suggest that 2012 was a very poor year for moths and species that rely heavily on caterpillars as a source of food for their nestlings experienced a sharp drop in productivity. The average number of fledglings produced per breeding attempt for both blue and great tit was significantly below average, the latter experiencing the second worst season on record. This poor performance was influenced by small clutches and high failure rates during incubation, as well as by a reduction in brood sizes, suggesting that adults were in poor condition when breeding commenced. The number of chaffinch fledglings per nest was at its lowest level since records began in 1966, by some margin. Losses during incubation were high and heavy rainfall may have had a direct impact, wetting the eggs when the female left the nest to feed.

A poor vole year

Many of the lowland owls and raptors feed primarily on volves, which anecdotal evidence suggests were in short supply during 2012, although the extent to which this paucity was influenced by the adverse weather conditions is not yet clear. However, heavy rainfall almost certainly affects the accessibility of these prey items, making it difficult for birds to hunt. Fledgling numbers of all three species for which preliminary trends are produced (kestrel, tawny owl and barn owl) were below average, although this difference was significant only for kestrel.

Flooding and water-logging

Exceptionally high levels of rainfall directly impacted on those species whose nests are vulnerable to flooding. Reed warbler is the most obvious example, demonstrating a significant reduction in every aspect of its breeding success as a result of rising water levels in ponds and lakes, leading to a fall in fledgling production of almost 36%. Increased river flow may also have contributed to the increase in failure rates of dipper nests during incubation.

Poor prospects for fledglings?

The results of the preliminary NRS analyses are broadly consistent with those of the BTO’s Constant Effort Scheme (CES), which calculates breeding success by comparing the numbers of adult and juvenile birds ringed each year at 120 sites across Britain & Ireland. However, there are some species (long-tailed tit, willow warbler) for which CES records a much more marked reduction in productivity during 2012. This difference suggests that young birds may have continued to struggle after leaving the nest, their lack of experience and relatively poor quality plumage making it much harder for them to cope with extreme weather conditions, leading to a drop in survival rates post-fledging.

Long-term impacts

Many of the species for which preliminary trends have been calculated are capable of producing large numbers of offspring each year, and so have the potential to bounce back rapidly following a poor breeding season provided conditions improve. However, the extreme conditions in 2012 resulted from a shift in the jet stream and it is difficult to predict how its position may be influenced by future climatic warming and the melting of the Arctic icecaps. If wet summers become more frequent, then we may witness long-term changes in the numbers of some bird species.

– including an average of 50 house sparrows every hour…

Report from British Birds

Since 1966, the UK has lost breeding birds from the countryside at an average rate of a nesting pair every minute, say conservationists in The State of the UK’s Birds 2012, published on Monday 19^th November.

The report estimates that there are 166 million nesting birds in the UK, compared with 210 million nesting birds in 1966. The house sparrow has seen one of the greatest losses of any bird in the UK. Although since 2000 house sparrow numbers have started to increase, the UK still has 20 million fewer sparrows than it did in 1966. The current population is estimated at around 10 million.

One of the report’s authors, Dr Mark Eaton of the RSPB said: “It is shocking to think that we’ve lost one in five of the individual birds that we had in the 1960s, especially when you think that the 44 million birds we have lost since 1966 is equivalent to the current adult human population of England and Wales.”

There have been many changes in the UK which have affected birds, most notably changes in the land use and the management of the countryside and seas – these can change the amount or quality of key resources needed by birds, such as suitable places to nest or a shortage of food in summer or winter. However, for some species, including the house sparrow, the precise reasons behind these declines aren’t fully understood.

The changing fortunes of two, related species further highlight the changes to the UK’s birds: the turtle dove and the collared dove. In 1966, the turtle dove was still a widespread bird with about 140,000 breeding pairs, whilst numbers of the collared dove were very low, as the species only began nesting in the UK in 1955. Today there are only thought be around 14,000 pairs of turtle dove nesting in the UK, whereas the collared dove had exploded to around one million pairs.

Cold weather is thought to have had a startling effect on bird numbers too. The wren, for example – still the UK’s most numerous bird – has lost an average of 835 individuals a day since 2000. But another garden bird, the chaffinch, has increased at a rate of 150 individuals per day.

Dr Andy Musgrove of the BTO, who worked on compiling these figures, said “We have learnt a great deal about bird numbers in the UK and, particularly, how they have changed through time. Amongst individual species, whilst there have been some winners, the number of losers is greater and the long-term picture is sobering. There is still more to learn though, and we need the continuing support of ever greater numbers of volunteer birdwatchers, on whose efforts all of these numbers are based”.

The State of the UK’s Birds report is a great example of ‘citizen science’ in action. Most of the information upon which the report is based is derived from the efforts of a network of skilled, volunteer ornithologists who contribute to national monitoring schemes like the UK’s Breeding Bird Survey and Wetland Bird Survey. Such schemes provide a high quality evidence base underpinning the work of government, conservation organisations and land managers in their joint efforts to conserve the natural environment and its wildlife. Here in Jersey we too rely on volunteer observers sending in their sightings to the Bird Recorder at the Société Jersiaise Ornithology Section. We in turn compile an annual Bird Report each year (copies are available from The Museum in St Helier and from the Durrell Visitor Centre). The Ornithology Section also takes part in most of the UK’s bird monitoring schemes such as the Breeding Bird Survey and BIRDS ON THE EDGE includes a bird monitoring project. Channel Islands bird numbers are not included in The State of the UK’s Birds 2012 but the current status of Jersey’s bird populations can be seen in our own report Conservation Status of Jersey’s Birds: Jersey’s bird populations in the 21^st Century.

The State of the UK’s Birds 2012 is produced by RSPB, British Trust for Ornithology and the Wildfowl & Wetlands Trust – and the UK Government’s statutory nature conservation. The report also includes the latest information on the number of ducks, geese, swans and wading birds spending the winter in the UK and an update on the internationally-important birds, including albatrosses and penguins, on the UK’s overseas territories.

The State of the UK’s Birds 2012 can be downloaded from the British Trust for Ornithology.

Report by Marc Woodhall and Glyn Young

On 11^th October all parties involved in trying to help secure the cirl bunting’s tenuous grip in Jersey and encourage it to spread met at Howard Davis Farm to discuss a strategy for the coming winter and next breeding season. Representatives of the Société Jersiaise Ornithology Section, National Trust for Jersey, Durrell, Grouville Tenants, Royal Jersey Golf Club in Grouville and Department of the Environment were present. Cirl bunting expert, Cath Jeffs from the RSPB, supplied advice via e-mail in advance of the meeting.

Summary of issues discussed

A brief summary of the history of the cirl bunting in Jersey was given including surveys from as far back as 1992 undertaken by the RSPB and Mick Dryden on behalf of the Société Jersiaise. In 1992, 21 singing males had been recorded primarily in three areas: Grouville Golf Course (GGC); La Moye Golf Course; St Brelade area (including St Brelade Bay and Pont Marquet). A steady decline continued from the 1992 survey until 2000 when no birds were seen. There were occasional sightings and reports until 2011 when cirl buntings were found on GGC on the bird monitoring transect that runs across it. Speculation as to why there has been a reduction in cirl bunting numbers has focussed on a combination of factors: they have never exhibited a strong breeding success in Jersey; there have been continued changes in agricultural practices resulting in a loss of winter habitat and feed availability; predation from sparrowhawks, cats and rats.

Discussions at the meeting were essentially focussed on four main areas:

1. The existing breeding habitat of the cirl buntings on GGC;
2. The monitoring and supplementary feeding of the birds on the GGC;
3. The winter feeding habitat of the birds;
4. The possibilities for cirl bunting conservation across other localities in Jersey.

1.   The existing breeding habitat of the cirl buntings on GGC

Current and proposed management of the non playing areas at GGC was outlined including the holm oak removal and gorse coppicing regime. Currently the Royal Jersey are working to a six year rotational plan to cover the whole course and are employing a combination of cutting smaller pockets and larger areas as well as replanting gorse where appropriate. There has also been a general reduction in the cutting regime of the rough across the course which was even more strictly applied around the current bird feeder sites. Grassland management regimes that are in place are designed to reduce the nitrogen load and promote finer fescue grasses. A consequence, however, of not managing the rough as intensively and also the rotational gorse coppicing and holm oak clearance has been an increase in the bracken stand which needs to be addressed.

In discussing the management currently being undertaken a number of initiatives being implemented to further enhance the marginal areas of the course and, hopefully, opportunities for cirl bunting and other birds were outlined. These ranged from keeping golf buggies out of the rough across the course and managing access for public and dog walkers in areas. It was also decided to relocate one of the existing bird feeders and to install a number of additional feeders in an area where forthcoming habitat management work is programmed.

2.   The monitoring and supplementary feeding of the birds on the GGC

The discussion about existing feeders focused on:

• Whether supplementary feeding should continue;
• Should there be a change in feed according to season, breeding and conditions;
• Should existing feeders be retained in place or moved.

Significant thanks were extended to Richard Perchard who has been monitoring the use of feeding stations, sterilising trays and topping up the food through 2011-2012. Birds have been fed the same seed mix throughout. The poor early season (in 2012) weather conditions meant that there was limited availability of grasshoppers (particularly) and there was discussion over the use of mealworms. It was decided that mealworms would be used at the start of the next (2013) breeding season if weather conditions were poor. It was further noted that the availability of grasshoppers would play an important role in the success of rearing young and it may be more beneficial not to leave grass uncut throughout the whole growing season as grasshoppers tended to become less abundant as vegetation became too long or rough. It was decided that supplementary feeding would continue year round for the time being and also to include a couple of extra feeders to be put out on the course.

Discussion about changing the location of feeding stations was prompted by the current use patterns, the threat posed by disturbance and the possibility of predation of the birds. The risk from predation is ever present and sparrowhawks undoubtedly pose a threat and feeders may need to be placed in suitably protective habitat like hedgerows to provide maximum cover when the birds are at their most vulnerable. Cats are also present at the GGC site and may be a serious threat as they undoubtedly are to green lizards and slow worms at the site. Rats and their control were also discussed.

3.   The over wintering feeding habitat of the birds

The discussion at the meeting echoed the comments by Cath Jeffs on the importance in providing suitable winter feeding habitat if the programme to increase cirl bunting numbers was to be successful (there would obviously be additional benefit for other farmland bird species). Evidence suggests that cirl buntings favour good hedgerow habitat and associated stubble fields resulting particularly from growing cereals. Suggestions for increasing opportunities of this kind of habitat included looking at Grouville Marsh and surrounding land as well as a more in-depth study to identify marginal / low intensity arable farmland within a 2km radius of the cirl bunting nesting site (2km thought to be the average foraging extent for cirl buntings).

It was confirmed that the golf course cirls cross the road to the hay meadow and beyond on Grouville Marsh. This meadow is cut annually Oct/Nov and that this will remain the case thus providing an undoubted seed source. There is also an amount of spring barley currently down in arable land (subsequently used for potatoes) within 2km of the GGC and it will be useful to identify these landowners/tenant farmers to understand their rotational plan and how it could be of benefit as potential food sources for farmland birds.

It may be possible for these landowners/tenants to receive financial support, in the form of grant aid through the Countryside Enhancement Scheme (CES), to cultivate cereal crops and provide overwintering feed sources. In addition the targeted improvement of hedgerows could also be supported through financial support from the CES.

4.  The possibilities for cirl bunting conservation across other localities in Jersey.

The historic locations of cirl bunting sightings suggest that a more targeted assessment for creating potential winter habitat, that includes feed availability, is undoubtedly worthwhile. At the very least it will provide benefit to a number of farmland birds and raise the profile of this area of conservation.

This could include influencing management at Pont Marquet, continuing ongoing discussions with La Moye Golf Course and identifying opportunities on land owned by the States of Jersey.

From Surfbirds

A new paper published this week reports that the rate of bird extinctions is accelerating at an alarming rate. Global patterns and drivers of avian extinctions at the species and subspecies level, published in PLoS One is free to download and reveals that 279 bird species and subspecies from across the globe have become extinct in the last 500 years. The study shows that species extinctions peaked in the early 20th century, then fell until the mid-20th century, and have subsequently accelerated.

“Until this study it had been hoped the rate of extinction was slowing”, said lead author Dr Judit Szabo. “Historically most extinctions have occurred on islands, particularly those in the Pacific, but most of the really susceptible species are long gone.”

The study shows that the destruction of native habitat for agriculture is currently the main cause of extinctions. Unsustainable hunting and the introduction of alien species, such as cats and rats, have been the main causes of extinctions in the past.

“Humans are directly or indirectly responsible for this loss”, Dr Szabo said.

The world’s nations had agreed through the Convention on Biological Diversity (CBD) to slow biodiversity loss by 2010, and having failed to reach this goal, the target has now been adjusted to 2020.

Report co-author Dr Stuart Butchart, BirdLife International’s Global Research Coordinator, said many species survive only because of conservation interventions. “This list would have been much longer were it not for the work being done around the world to stop extinctions. But we need to scale up our efforts substantially to avoid further human-induced extinctions”, said Dr Butchart. “Our analysis provides the most detailed picture to date of recent extinctions and will help us identify strategies to tackle the loss of biodiversity and halt future human-induced extinctions. The Conference of the Parties of the CBD in Hyderabad, India will need some firm action to achieve its target of achieving this by 2020.”

In Jersey we have seen the loss from our island of several bird species over the last 20-30 years. While none of these birds are in imminent threat of global extinction, each loss represents the slow but steady crumbling away of their ranges and populations. BIRDS ON THE EDGE hopes to help prevent the disappearance of further birds and return some to our Island.

News from BTO

Finch trichomonosis, caused by the protozoal parasite Trichomonas gallinae, was first recognized as an emerging infectious disease of British passerines in 2005 and is detailed in a new paper published this week. The first year of seasonal epidemic mortality occurred in 2006 with significant declines of greenfinch Carduelis chloris and chaffinch Fringilla coelebs populations. In the newly published paper it is demonstrated that large-scale mortality, principally of greenfinch, continued in subsequent years, 2007–2009, with a shifting geographical distribution across the British Isles over time.

Consequent to the emergence of finch trichomonosis, the breeding greenfinch population in Great Britain has declined from c. 4.3 million to c. 2.8 million birds and the maximum mean number of greenfinches (a proxy for flock size) visiting gardens has declined by 50 per cent. The annual rate of decline of the breeding greenfinch population within England has exceeded 7% since the initial epidemic. Although initially chaffinch populations were regionally diminished by the disease, this has not continued.

Retrospective analyses of disease surveillance data showed a rapid, widespread emergence of finch trichomonosis across Great Britain in 2005 and the paper’s authors  hypothesize that the disease emerged by T. gallinae jumping from columbiforms (Pigeons and Doves) to passeriforms (Songbirds). Further investigation is required to determine the continuing impact of finch trichomonosis and to develop our understanding of how protozoal diseases jump host species.