24 mei 2008

On the individual ringing and rings

Certainly whatever bird is ringed by a scientist it must have obligatory a small metal ring, preferably life-lasting steel nowadays, that is reported be the ringer to the national Ringing Center and also shall be reported whenever a bird is re-captured or found dead. But these metal rings with small numbers are extremely hard if not impossible to be read from the distance. Therefore about forty-fifty years ago some smart ringers started to use additional light-weight colour plastic rings, and at least in the latest twenty years such plastic rings for rather large birds, such as Oystercatcher and larger, are numbered and coded individually. To avoid confusion between ringers, countries and colour-marking schemes there is also international coordination (for wader done in the British Trust for Ornithology). Since 2002, when a good set of individually numbered rings was made for the White Sea Oystercatchers with the Dutch KNIP funds, there are three types of colour rings legally used for individual colour-ringing of the White Sea Oystercatchers. On the first drawing all the schemes are shown in a symbolic way, and the photo below shows the rings themselves.
For some practical reasons in the last years I prefer to use the rings that are made in Canada (orange and yellow in the right or the blue below), they are thicker and proved to be more durable though there is yet little statistics to say it 100%.

The greatest advantage of these colour rings is that the individual code can be read at a distance. The latter in fact depends on the telescope and bins that are used; in the former times I sometimes needed 40 minutes to 1>5 hour to read a code with the x45 telescope, but currently with the good Zwarovski x60 it is really easy.

What I did not manage since last year is the close-up photography – so the individual birds cannot be “adopted” with the photo. And at the distance the rings look just like on the two photos below. But this year I hope to catch up on the “ID portraits” as well, so that the stories will be linked to well-seen numbers on the Oystercatcher legs on the photo.

Whenever you see an Oystercatcher or any other bird with such colour rings – please try to "read the rings" and note as much as possible (species, location and colour of rings and numbers/letters, location of metal ring etc.) – and please report it to the Ringing Center or similar agency in your country, usually it is 1 per country. Who knows, may be you have seen “my” White Sea Oystercatchers already not yet knowing it!

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