Monthly Archives: September 2012

Chough reports: July and August 2012

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Reports from Liz Corry

JULY 2012

Captive breeding at DurrellChoughs in display aviary. Photo by Liz Corry

All of the choughs have started to moult: juveniles around the 11th whilst the breeding pairs started a few days later.

Captive breeding at Paradise Park

The sexes of the three chicks bred this year have been confirmed as 1 male and 2 female.

AUGUST 2012

Captive breeding at Durrell

Chough at food bowl. Photo by Liz CorryAll the choughs are now being given their non-breeding/winter diet whereby the protein levels are reduced, i.e. the ox heart has been removed and less insects are given. In past years we have given mixed corn in winter as wild choughs are known to forage in cereal fields when insect numbers are low. However, the choughs in captivity at Paradise Park and at Durrell rarely touch the corn so it has been removed from the diet completely.

The breeding pairs have now finished for the season. Normally they would be integrated back into the display flock; however, due to the release planned for this autumn/winter we will keep the breeding birds separated from the potential release birds for now.

Display flock

Liz trains the choughs. Photo by Fiona MarchantThe low productivity of chough chicks this year means that the trial release cohort will consist of the three chicks hatched at Paradise Park this year and another three selected from the older juveniles in the display aviary at Durrell. In preparation for their release these birds will be trained to fly to target boards for food as this will help with the supplementary feeding once in the wild and allow the keepers to call the birds back if they need to be shut away in the release aviary.

Chough target board. Photo by Liz CorryTraining began at the end of July and looked promising at the start of August. The birds are accustomed to flying down for food, but they need to learn to respond to their cue for food. Working with a large group rather than training on an individual basis has proved challenging. We increased the number of target boards so that each bird has a chance of getting to food which in turn strengthens the learned behaviour. However, there are still a couple of individuals who hang back whilst the dominant birds fly down first and take all the food. We will continue with the training and looking at ways to improve the birds’ success.

Notes 

All the juvenile choughs have somehow managed to lose an ID ring. Five have lost their metal rings and the sixth has lost its plastic ring. One metal ring has been recovered and it looks as if it has been prised open. All six birds can still be identified but new (and improved) rings will be added before any release.

 

Turtle dove: the UK’s most threatened farmland bird

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News from the RSPBTurtle dove in St Ouen's Bay. Photo by Miranda Collett

Since Operation Turtle Dove was launched by the RSPB, Conservation Grade, Pensthorpe Conservation Trust and Natural England in May, the reporting hotline has had 429 calls reporting the elusive bird.

Norfolk came top as the county with the most reported turtle dove sightings (112), second was Suffolk (69), closely followed by Cambridgeshire (61), with Essex (32), Kent (29), and Lincolnshire (20) coming fourth, fifth and sixth. In Jersey we may have had only one breeding pair this year and it is unclear whether these were successful in rearing any young.

Alison Gardner from the RSPB’s Operation Turtle Dove, said: ‘It’s great that we’ve already had so many people supporting Operation Turtle Dove and looking out for these birds.

‘At this time of year, just before turtle doves Streptopelia turtur head off on migration, juveniles and family groups are easier to spot so we’re hoping for some more reports before the season’s out and are appealing to anyone who spots a turtle dove to call and give us as much information as possible.’

Turtle dove numbers have fallen dramatically since the 1970s with just nine birds now for every 100 there were 40 years ago. Once widespread across much of England and Wales, the species has been lost from many areas and are now primarily restricted to areas of East Anglia and southern England. Not so long ago, turtle doves were widespread in Jersey in summer but are now close to disappearing.

Reasons for the turtle dove’s population crash are not fully understood. However, since the 1960s the diet has changed from mainly the small seeds of wild plants to one dominated mainly by crop seeds, which are scarce early in the breeding season and may provide a poorer quality diet for turtle doves.

Simon Tonkin, the RSPB’s senior farmland advisor, said: ‘turtle doves feed almost exclusively on seeds. Many of the traditional wild foods are now scarce on farmland and it is uncertain whether crop seeds are providing an adequate substitute. Additionally, turtle doves prefer to nest in hedgerows or areas of scrub over 4m tall, habitats that are less common than in the past.’

Operation Turtle Dove’s hotline has also received a number of calls from people with large gardens, often backing onto agricultural land, who’ve spotted turtle doves taking food from their bird feeders and using the garden pond to drink from and bathe in.

RSPB researchers have also found nests in gardens and amenity areas bordering farmland, which may reflect a shortage of resources on agricultural land, meaning the birds are forced to find alternatives to survive.

Simon added: ‘This means farmers and householders in rural areas have a huge role to play in the conservation of this beautiful bird. While there are some great advocates out there doing all they can, it still needs more support.’

To report your turtle dove sightings, call the Operation Turtle Dove Hotline 01603 697527 or you can submit your sightings to turtledove@rspb.org.uk Please also send in your records to the Jersey Bird Recorder at the Société Jersiaise ornithology@societe-jersiaise.org or through Jerseybirds.

The RSPB has two advice sheets on how to help turtle doves, one for farmers and one for people with large gardens or outside spaces that back onto arable fields and are available free by emailing turtledove@rspb.org.uk

The emergence and spread of finch trichomonosis in the British Isles

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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.

Greenfinch in winter. Photo by Mick DrydenConsequent 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.

 

Woodpigeons hit record high in UK gardens

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From BTO press release

Woodpigeon. Photo by Mick DrydenWoodpigeons are fast becoming the UK’s most recorded garden bird. Recent results from the year-round BTO Garden BirdWatch survey show that 87% of gardens have been visited during a typical week this year – more than by robins, great tits or house sparrows.

The march of woodpigeons into UK gardens appears to be unstoppable. Nationally, only blue tit (90%) and blackbird (95%) now stand in their way from taking top spot. In some areas, including Hertfordshire, Nottinghamshire, Warwickshire, The West Midlands and West Sussex, it appears that woodpigeons are already top of the podium. In Jersey, these pigeons are in the Top 10 species recorded in gardens but still face competition from old favourites like robins, house sparrows and blackbirds.

Their growing success in gardens is likely to have been caused by several factors. In the UK countryside, increased production of oil seed rape has provided fresh ‘greens’ to eat throughout the winter. Increased numbers appear to have spilt over into gardens, where plentiful food and nesting opportunities are being utilised. 

BTO can also reveal that woodpigeons are reaching deep into towns and cities, now being seen more often in suburban than in rural gardens. Despite bringing a welcome sense of the countryside with them, their large appetites make woodpigeons divisive garden guests. Woodpigeons. Photo by Mick DrydenWe see the same picture here in Jersey where woodpigeon numbers are going up and the birds themselves seeming to become more confiding each year.  Not only is this bird very common all through the year but in autumn we see remarkable numbers overflying the Island as some populations escape the colder northern winters. These migrants don’t seem to join our residents and often huge flocks can be seen heading out to sea from Noirmont. See updates during the migration

Back in the gardens, there are steps that householders can take, however, to ensure that there is enough food left over for smaller birds. Feeder sanctuaries, for example, which are metal cages through which smaller but not larger species can pass to access food contained inside, are a useful tool. Smaller perches might also dissuade woodpigeons from trying to act like a blue tit on hanging feeders.

There is, however, also much to love about this quirky species. Did you know, for example, that woodpigeons are one of very few bird species that produce crop milk – which is similar to mammalian milk – to help them rear their young? They are also true breeding champions, having been recorded nesting in every month of the year!