Control

Post date: Aug 15, 2014 5:46:26 PM

Another session, another surprise. The penultimate CES session of the year took place this morning, which started rather chilly (c. 8ºC) but warmed up to comfortable, late-summer temperatures (c.21ºC). The first two rounds were by far the best, with 15 and c.7 birds respectively, but it then slowed down quite considerable, resulting in another decline in captures (42, plus nine retraps) and also of species (only 9, though a Dunnock escaped without a ring!). It was nevertheless quite a useful session for my visitors to get reacquainted with Marsh/Reed Warbler in-the-hand identification, and it allowed to take quite a few samples for a malaria study. This session, I had the pleasure of having my office mate (Michi Tobler) and our post-doctoral host (Dennis Hasselquist), as well as their daughters, helping out and learning.

A juvenile Marsh Warbler/Kärrsångare (Acrocephalus palustris)

An adult Reed Warbler/Rörsångare (Acrocephalus scirpaceus), originally ringed in Belgium

The highlight of the session must have been the capture of a Reed Warbler with a Belgium ring, which constitutes my first foreign control in Sweden (although last year one of my Reed Warblers was also recovered in Belgium). Is is always a pleasure for a ringer to get these controls as the large movements of these small birds become more readily apparent, but the importance of this kind of data has declined considerably due to the development of new technologies (such as geolocators) providing much more detailed information about their whereabouts.

The ring from Belgium (12652873 MUSSGNAT BRUSSELS)

A Reed Warbler with a Belgium ring would be the most expected foreign control, given the abundance of this species and the amount of ringing taking place in Belgium during migration. Hopefully, there will be more foreign controls and with greater interest in the near future. I would be particularly keen on retrapping one of my Swedish birds in Portugal, but I guess the probability is extremely low!

Júlio M. Neto