Wednesday, 21 November 2012

Where do all the birds go?

Since it started in 1909 ringing has answered some of the many questions regarding bird ecology and movement. We know, for example that swallows do not hibernate in the mud at the bottom of ponds but in fact migrate thousands of miles to southern Africa. We know that many species that breed on the continent move east to spend the winter in the relatively milder climes of Britain.

More recently ringing has highlighted interesting changes in migration linked to climate change. Over recent decades the numbers of blackcaps wintering in Britain has increased, with ringing recoveries indicating that these birds are not simply individuals from our summer breeding population. Instead they are birds that breed in central Europe, which rather than moving south for the winter are heading east to Britain. With milder winters those that do head our way are finding conditions more favourable and more of these visitors are able to survive. Research shows that blackcaps wintering in Britain arrive back on their breeding grounds some two weeks before those wintering around the Mediterranean; this may well give them a competitive advantage when it comes to raising more chicks and could explain why the tendency to winter in Britain has spread so rapidly through this population (BTO Bird Table, 2005).

Male blackcap

While such findings on this grand scale are extremely interesting, and as a ringer I am proud to be contributing to such discoveries that will provide valuable information for conserving our bird populations, sometimes it is the stories of individual birds, which I have personally ringed that are the most gripping.

Lodge Farm, a small pocket of garden and open paddocks nestled in the middle of Thetford Forest. Surrounded by pine plantation and deciduous wood, the garden provides a regular supply of food and also a source of water in the form of a beautiful koi carp pond. During the winter the site attracts hundreds of finches, from siskins and redpolls to bramblings and chaffinches. Over the last three years we have regularly ringed this site, mainly during the winter months, and over the years a number of the birds we've ringed have been found elsewhere, usually caught by another ringer. In addition we've caught birds at the farm which were originally ringed elsewhere in the country. Most of these birds come from or have been recaptured at sites in and around Thetford, with a couple caught in the wider East Anglia region. Occasionally though some individuals are from a little further afield. 

View Complete recoveries by Lee or Rachael in a full screen map

In March 2012 I ringed a lesser redpoll at the farm, one of hundreds perhaps ringed last winter. In October 2012, that little, streaky brown and white bird, with a red spot on its head, was caught 473 km away in the Lothian region of Scotland.

In 2008 a certain Lee Barber, in his first winter of ringing in Suffolk at the farm, ringed an adult male brambling. In May 2011 that brambling was caught by a ringer on its breeding grounds 2078 km away in Norway. During that time that bird would have crossed the North Sea at least six times, covering a distance of at least 12500 km!

Stunning male brambling -
heading back and forth between Lodge Farm and Scandinavia

Then there are the three siskins, all originally ringed in parts of Scotland and all subsequently caught at the farm. In February 2012 a female siskin was ringed in Devon, 35 days later she was caught at the farm

While there is nothing exceptional about these recoveries - we know that brambling’s breed in Scandinavia and migrate to our shores in large numbers during winter and we know that lesser redpolls in Thetford Forest are there to winter, breeding predominantly in Scottish forests – they form the pieces of the jigsaw that is understanding bird movement and habitat use. Knowing that I personally handled that bird, carefully looked at its feathers to understand its moult and age, took those biometrics, makes such pieces extra special. 

Sunday, 11 November 2012

Flying Solo

After a day of grey, drizzly rain while it seemed the rest of the UK basked in wonderful November sunshine, I woke on Sunday morning to a cold, crisp, clear night sky that was just starting to lighten with dawn. The grass was like frozen green beans, crunching under foot, while mist clung to the parks and open areas of the forest. When the sun rose the trees framing the paddocks at the farm blazed fiery red and orange, glowing against the brilliant blue sky. Surrounded by the trees and bushes of the farm’s garden, the mist nets remained in the shade, perfect for catching birds.

Goldfinch with a more unusual orange face

Today at the farm it was just me and two nets. Being a ‘C’ permit holder means I can ring on my own. However most of the time I ring with Lee, and a group of others since the farm is not one person’s site. Today however I was making the most of the fact that Lee, and most of the others were in Scotland.

After the beauty of the morning, the birds did not disappoint. Although there was no sign of the siskins and redpolls that often dominate the catches in this garden during winter, there were plenty of tits around including blue, great, coal and marsh tit. Even before I had finished unfurling my nets I had caught two coal tits, which unlike many of the other tits have had a reasonably successful breeding season. There were also plenty of goldfinches, tinkling away in the tops of the trees, before piling down to the feeders and into the nets.

As the sun shifted position it started to catch the nets, making them more visible and in return the number of birds caught started to slow. Still, enough time to catch a male great spotted woodpecker, screeching blue murder as I tried to get him out of the net with my fingers still in tact. It only half worked, yes I got him out fine and yes I still have all my fingers, its just now they know how a tree feels when a woodpecker starts hammering at it!

Male great spotted woodpecker

Bird of the morning had to be a beautiful adult male brambling, with his striking orange, white and black plumage, with flashes of yellow under the wing this bird is one of the stars of winter ringing.

Stunning male brambling

With the final net round came on last surprise for my mornings solo ringing - its certainly    a little more unusual to catch a woodpigeon in our mists nets!

One final surprise in the nets