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.

http://batchgeo.com/map/851d6b5c8724be057e4fe6ebe37bbe58
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.


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