Bird Ringing

Dead birds can talk - The value of bird ringing.

This note has been put together from a newsletter contribution by Brian, a posting by Barbara and a reply by Steve. Robert contributed the photograph.

How do we know about the tremendously long journeys (many thousands of miles) which some birds make? They tell us when they are dead!

It’s not as silly as it sounds. Bird ringers spend a lot of time and effort trapping and ringing birds. Only a small percentage of the birds that are ringed are ever seen again, either alive or dead but the small numbers that are recovered allow a picture to be built up both of survival rates and of dispersal patterns. Data built up over a long period of time can help us to understand population fluctuations.

We saw the front end of the process during a visit to Tsavo West National Park in Kenya which coincided with the arrival of a team of bird ringers from England. They stay there for two weeks every year and we were invited to see them in action. They use large floodlights to encourage the birds down where they are caught in mist netting.

We watched them weighing, measuring and ringing several species familiar to us back home, including Whitethroat and Barn Swallow. Other birds caught were Barred Warbler, Thrush Nightingale, River Warbler and Marsh Warbler, all on migration from Eastern Europe, Poland and Russia. None of the birds seemed distressed and on release flew off happily into the nearby bushes.

An example of the other end of the process occurred when our Bird Group visited Lothian, Scotland for a weekend trip in 2009.

Shag%20%28Dead%20Shag%29.JPG

We found a dead Shag on the tide-line at Yellowcraig Country Park. Because it had been ringed it was possible to fill in an on-line report to the British Trust for Ornithology (BTO). Subsequently a letter arrived giving the history of the bird, which had been ringed, as a nestling, on the Isle of May on 15th July 2008. We found it on 8th February 2009 so it had not survived its first winter (it was just 218 days from initial ringing to when we discovered it), and it had moved just 19km south-west from the Isle of May, in the mouth of the River Forth.

This example shows the importance of reporting such records which help to form the bigger picture and improve our knowledge of birds and their behaviour. Filling in the details on line-shows how IT has simplified and aided information gathering. It is so much easier than it used to be as one of our members remarked:-

“This reminds me of discovering a dead Pole Cat near Redesmere over 20 years ago while out cycling. This was just a few weeks after attending a talk about their come-back where they made an appeal for any Cheshire sightings. I rang the Vincent Wildlife Trust who asked me to collect the dead body, freeze it and post it to them in Worcestershire. The family were not too happy at the addition to the freezer and were quite relieved when I posted it.

So if you find a dead bird, it is always useful to check whether it is carrying a ring, and if it is, then it can easily be reported via the BTO website. It provides some reward for the ringers and can help to provide important information in building up a picture of how birds are faring.

Finally, to bring you completely up to date, ringing may soon be a thing of the past. Those who watched the BBC Autumn-watch programme recently will know that birds can be fitted with a miniaturised GPS! It is a geo-locator which stores data which can be down loaded to reveal exactly where the bird has been. Isn’t technology marvellous?

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