We've made the first visit to a couple of sand martin colonies that have been well watched over the last few weeks. We time our first visit to be a few days after the first juveniles have fledged. This ensures the colony is very well established and gives us a good chance of catching locally grown juveniles and catching a good number of adults.
Our first visit to the Burrow colony was a quiet affair with just 3 of us there so only covered a small proportion of it however in return we caught 82 new birds of which 11 were juveniles. Of far more interest were the 30 retraps and two controls.
17 of the retraps were ringed as juveniles (16 from 2010 and 1 from 2009) at colonies along the Lune. Most of these were early season birds (up to mid June) suggesting that juveniles at colonies early in the season will return there. Later in the season a lot of the juveniles are wandering between sites so have a much lower return rate.
13 of the retraps were ringed as adults, mostly at Burrow in 2010 with a couple from Arkholme (6km away) with 3 from 2009.
The two remaining birds were controls (ie not ringed locally). One was carrying a French ring which has a very similar ring number to one ringed in September 2007 in Charente-Maritime (Thanks to the on line reports on the BTO website). The other is a complete mystery - L088327.
At the same time Pete made a visit to a small colony in the Bowland fells and caught a total of 32 birds including 4 retraps from previous years (all ringed as adults), and 3 controls (in this case moved more than 10km) which were from Arkholme (2) and Burrow. One ringed as an adult female in 2009 and the other two as juveniles in 2010.
We hope to make visits to more smaller colonies this year to try and find out where more of our 918 juveniles from 2010 have gone.