A whoosh net catch of twite taken this morning at Heysham Harbour consisted of what at first seemed a high proportion of unringed birds, compared to that observed over recent weeks. The catch, of 37 birds, comprised 21 unringed and 16 retraps. Recent counts have suggested only 16 unringed birds out of various flocks totalling close to 80.
This is actually not so surprising, when the circumstances are revealed. Time was short this morning so I only wanted to deal with one catch. In addition, the wind was gusty and becoming stronger all the time. Whilst setting the net, groups of Twite were flying about above me and when finished I walked towards the car to fetch some fresh seed. Immediately, birds began to line up on the fence and even drop onto the seed already there.
A large group of birds quickly gathered on the seed - after waiting for a safe gap in the arriving birds the net was fired, with many more still on the fence. This is not usually a good idea if further catches are intended.
However, it does clearly show that unringed birds (that have not encountered a whoosh net before) are less wary of the net paraphernalia and the "old hands" take their time before dropping in. The retrapped birds had all been ringed in 2010 - no older birds were recaught.
This is not surprising really, but does show that care might be required when undertaking analyses of retrap information.
ajd
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