27 January 2012

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.

19 January 2012

It's Loony that we only get one a year!

Birdfacts quote: "In Shetland Red-throated Divers were considered one of the best weather indicators, short cries (or flying inland) indicated fine weather, long, plaintive ones (or flying out to sea) wet weather." Although probably not a statistically significant weather predictor, the Red-throated Diver is an amazing bird.

Occupying shallow ponds and lochs in Scotland during the summer and heading out to sea in winter, this bird is tricky to see, let alone ring, unless you live on Shetland, Orkney or the Western Isles. In 2010 we ringed 91 birds and all apart from three were ringed as chicks from broods of one or two.

In 2010 we had one report of a Red-throated Diver, ringed in Sweden (red pin) on 31 July 1996 and found fresh dead on 6 February 2010 in North Wales (1326km). We have just heard that we have now had our annual quota of foreign ringed Red-throated Divers for 2011 in the form of a bird ringed in Finland (blue pin). This bird was ringed on 28 July 2008 and found dead on Stronsay, Orkney on 13 November 2011 (1753km).

View Red-throated Diver in a larger map

Thanks to Jill Pakenham for the photo.

10 January 2012

Tricky Customer

From late 2005, we began to receive reports of dead or dying Greenfinches, cases that were subsequently linked to an emerging infectious disease called Trichomonosis. This disease was already known from pigeons and doves but cases in wild finches were unknown. During the outbreak that followed (notably during 2006 and 2007) significant numbers of Greenfinches and Chaffinches died. In areas where the outbreaks were most pronounced we saw Greenfinch and Chaffinch populations decline by 35% and 21% respectively, representing mortality in excess of half a million birds.

Other species have been infected including Goldfinch, Bullfinch, House Sparrow and Tawny Owl. Only last week we had a report of a ringed Tawny Owl that had to be put to sleep due to necrotic Trichomonosis in the throat.

Unfortunately in 2008 Trichomonosis was discovered in Fennoscandia and was the likely result of migrating Chaffinches carrying the disease from the UK.

During the year there used to be a particular peak in reported cases during the autumn, due to the warm wet weather helping the parasite survive outside its host. More recently this trend is much less distinct. The reason for this is not fully understood.

Thanks to Jill Pakenham for the photo.

03 January 2012

Happy New Year!

With gale force winds and driving rain, the start of 2012 isn't ideal for ringing birds but while this settles down, its time to deal with the last of the 2011 recoveries.

After the Christmas period we have received quite a few reports of wildfowl and garden birds being found dead. Some wildfowl and gulls have been recorded alive by the dedicated ring readers at their local park. It won't take us long to process all the reports up to the end of 2011 and at the same time we will be loading all the data coming in from ringers of all the birds they've ringed and recaptured in that time.

The Demography Team would like to thank all of our ringers for their work over the past year. All the data collected is vital to conservation and 2011 looks likely to be another record breaker. This time a year ago we had received fewer ringing records and in the end we had over a million birds ringed in 2010! So this year it's looking good to reach over a million again! We'll let you know when we have completed the final load.

Thanks to Rob Robinson for the photo.