Tuesday 9 December 2008

Colour-ringing

Colour-ringing is a valuable research technique that enables studies to be made that would be impossible using just the usual numbered metal ring. The main and obvious advantage is that a colour-ringed bird can be identified as an individual without the need for it to be re-captured and the ring number read. It follows from this that repeated sightings of a bird will yield much more information than could ever be hoped for from conventional ringing. Some colour-ringing projects involve behavioural research in a restricted area such as detailing the day-to-day activities of particular birds, while others are concerned mainly with movements between areas and following and discovering the timing of seasonal migrations. The website http://www.cr-birding.be/ maintained by Dirk Raes has details of all the European colour-ringing projects and this is our prime source of information.

There are lots of colour-ringed birds here on the Algarve. Over the last few years we’ve seen lots of Greater Flamingos and Spoonbills, several Slender-billed Gulls and Audouin’s Gulls, a Black-tailed Godwit and at least one Black-winged Stilt. More often than not the Flamingos, Spoonbills and gulls are too far away for us to read the rings, while Black-tailed Godwits in particular are nearly always in such deep water that we can’t see whether they have rings or not. Sometimes it requires a lot of time and patience to get the ring details and be sure that it has been read accurately. To be honest, we have to be in the right mood but when we do get ring details and send off a report we are always interested in the response we receive - if we get one! Dirk Raes warns that while some colour-ringing schemes provide swift replies, others don’t reply at all, which we find both surprising and disappointing. It is the feedback we receive that is our motivation for reading and reporting colour rings. We are never going to be in the mood to read rings on some species because we know that we ourselves will never learn anything as a result of reporting them.

Colour-ringed Spoonbill

Recently (27th November) we saw a colour-ringed Spoonbill at Alvor and sent the details to Otto Overdijk in The Netherlands. We had a reply almost immediately. The bird, probably a male, had been ringed as a nestling on 29th May this year in Schleswig-Holstein, Germany. It was later seen in Denmark (August) and was reported from Lagoa dos Salgados here in the Algarve on 8th October. Thank you Otto for sharing these details and for replying so quickly.

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