GBW

Scientists from the Zoological Society of London (ZSL), University of Oxford, the British Trust for Ornithology (BTO) and RSPB report on the impact avian pox is having on great tit populations.

Avian pox has been recorded in British bird species such as house sparrows and wood pigeons for a number of years. However, the emergence of a new strain of this viral disease in great tits is causing concern amongst vets and ornithologists.

Wildlife vet Dr Becki Lawson from ZSL says: “Infection leads to warty, tumour-like growths on different parts of a bird’s body, particularly on the head around the eyes and beak."

“Although the disease can be relatively mild in some species, great tits suffer severe growths that can prevent them from feeding and increase their susceptibility to predation,”

Dr Lawson added.  "Whilst a range of tit species are susceptible to this novel form of the disease, detailed monitoring of birds in Wytham Woods by scientists at the University of Oxford show that great tits are by far the most susceptible."

“Although recovery from infection can occur, our results show that this new strain of avian poxvirus significantly reduces the survival of wild great tits and has particularly large effects on the survival of juvenile birds,” says Dr Shelly Lachish of the Edward Grey Institute at Oxford University

“Based on the numbers of affected great tits that we have observed at Wytham Woods, our models do not predict that this new disease will cause an overall population decline of the species. However, pox-affected populations have lower yearly growth rates. Hence, they are likely to have greater difficulty in recovering from other environmental factors that might reduce their numbers,” Dr Lachish added.

With help from the public, scientists at the RSPB and ZSL have tracked the disease, which has spread rapidly in five years from south-east England to central England and into Wales. The annual seasonal peak of observed cases occurs in the early autumn months and incidents continue to be reported at this time of year.

Genetic studies on the virus show that it appears to be the same strain seen previously in Scandinavia and more recently in central Europe, and is unlikely to have originated within Great Britain. BTO data on bird movements confirms that great tits rarely migrate outside the country. The spread of the virus to Britain is, therefore, thought to have occurred through the arrival of an infected vector, such as a mosquito.

Funding from NERC (the Natural Environment Research Council) enabled the detailed research reported here, and scientists are continuing to work together to monitor impacts of this new avian poxvirus strain on the population of great tits in the UK. They are calling on the public to assist in these efforts by reporting any signs of disease in garden birds to the RSPB, and have also highlighted that avian pox is not known to be infectious to humans or other mammals.

Notes for Editors

1. Sightings of birds displaying symptoms of avian pox should be reported to the RSPB Wildlife Enquiries Unit preferably online via: http://www.rspb.org.uk/advice/helpingbirds/health/sickbirds/avianpox.aspx or by telephone on 01767 693690.
2. Avian pox is caused by avian pox virus.  Affected birds develop warty or tumour-like growths, on the head (particularly next to the eye or beak), legs, wings, or other body parts. The growths are usually grey, pinkish, red or yellow in colour. 

   Whilst a range of species are known to be susceptible to avian pox infection (e.g. house sparrow, wood pigeon, dunnock, starling), the recent cases of infection in tits are not typical of the type of avian pox we are used to seeing because the lesions are particularly large. In most cases lesions are distributed on the head around the eyes and beak. The extent to which different bird species are susceptible to different avian pox virus strains is unknown.

   The virus is spread between birds by biting insects that carry the virus, direct contact with other birds and indirect contact, possibly through contaminated bird feeders. Avian poxvirus is not known to be infectious to humans or other mammals.

   Although large pox growths can be very characteristic, smaller or medium-sized growths can easily be confused with a number of other conditions, such as ticks. The disease can only be confirmed by further investigation, such as post mortem examination and subsequent laboratory tests.

   Whilst supportive treatment can be attempted in captive birds, effective treatment of free-living birds under field conditions is not possible. Maintaining optimal hygiene at feeding stations can help to prevent outbreaks of disease. Where disease outbreaks occur, temporary removal of supplementary food may be appropriate to reduce close congregation of birds and reduced the risk of further disease transmission.

   For further information: http://www.ufaw.org.uk/gbhi.php

3. Founded in 1826, the Zoological Society of London (ZSL) is an international scientific, conservation and educational charity: our key role is the conservation of animals and their habitats.  The Society runs ZSL London Zoo and ZSL Whipsnade Zoo, carries out scientific research at the Institute of Zoology and is actively involved in field conservation overseas. For further information please visit www.zsl.org
4. University of Oxford.  The Edward Grey Institute is research institute in the Department of Zoology at the University of Oxford, and conducts research into the ecology, behaviour, evolution and conservation of birds in their natural environments. For further information on the Edward Grey Institute at the University of Oxford, please visit: http://www.zoo.ox.ac.uk/egi/
5. The British Trust for Ornithology (BTO) The BTO is the UK's leading bird research organisation. Over thirty thousand birdwatchers contribute to the BTO's surveys. They collect information that forms the basis of conservation action in the UK. The BTO maintains a staff of 100 at its offices in Norfolk,  Stirling and Bangor, who analyse and publicise the results of project work. The BTO's investigations are funded by government, industry and conservation organisations.For further information, please contact: Mike Toms, Head of Garden Ecology, t: 01842 750050, Email: mike [dot] toms [at] bto [dot] org www.bto.org
6. The RSPB speaks out for wildlife, tackling the problems that threaten our environment. The RSPB has more than one million members, over 13,500 volunteers, 1,300 staff, more than 200 nature reserves, 10 regional offices, four country offices... and one vision - to work for a better environment rich in birds and wildlife. www.rspb.org.uk   the results of project work. The BTO's investigations are funded by government, industry and conservation organisations.

Keep an eye on your bird food - squirrels are coming

Keep an eye on your bird food – squirrels are coming! Householders who record garden wildlife through the year-round British Trust for Ornithology (BTO) Garden BirdWatch survey have revealed a big influx of Grey Squirrels over recent weeks. Garden use is currently up by a third compared with the same period in 2009–2011.

Seed and nut availability appears to be patchy in the countryside this autumn, leaving wildlife in search of alternative food. For Grey Squirrels, as well as for birds, garden bird feeders provide a nutritious fix. While some householders welcome squirrels into their gardens, others consider them to be pests that chomp through expensive bird food and feeders.

BTO research shows that many bird species, such as Jay, Coal Tit and Nuthatch, turn to gardens in greater numbers when seeds, such as beechmast, are scarce during autumn and winter. It is, therefore, possible that there will be increased competition at garden feeders over the coming months, not only between birds but also between birds and Grey Squirrels.

Dr Tim Harrison, BTO Garden BirdWatch, commented: “Expect some fireworks at garden feeders this autumn and winter. Large numbers of birds are already gathering, with species such as Chaffinch and Starling being joined by their Continental cousins. Even the colourful Brambling has been spotted at garden feeding stations, which is remarkably early in the year for this seed-eating winter visitor.”

He continued: “With many more Grey Squirrels than normal also on the scene, competition may be intense. Unlike many other small mammals, Grey Squirrels do not hibernate and so they will be looking for food throughout the winter. To help ensure that garden birds get enough to eat, householders should keep their feeders topped up, provide a range of foraging options and consider using squirrel deterrents.”

BTO’s top tips if you wish to deter squirrels from bird feeders:

1. Guard – use metal cages through which small birds can pass to access bird food but adult squirrels and larger birds are excluded.
2. Gravity – spring-loaded bird feeders use a squirrel’s own body weight to close up the feeding ports when it comes to eat.
3. Baffle – domes attached to feeder poles/strings can be effective. Vaseline on smooth feeder poles might also help to give squirrels the slip.
4. Distract – create a separate feeding area for squirrels away from your bird feeders where they can easily get food.
5. Spice things up – chilli powder dusted onto bird food will help turn up the heat on your furry guests, without bothering your birds.

Help chart the fortunes of birds, squirrels and other garden wildlife through the BTO Garden BirdWatch project. For a free enquiry pack email gbw [at] bto [dot] org or telephone 01842-750050.