Sunday, 18 September 2011

Checking Bridges

Every September/October I try to check each of over 100 known Dipper roost sites around Shropshire and Mid Wales for roosting birds. Last night was the first checking bridges on our main study site on the catchments of the Rivers Teme, Clun and Onny, on the Shropshire/Powys/Herefordshire border. I met up with Lloyd at 8.30pm in Knighton and the aim was to check all the bridges on the River Teme above Leintwardine. We finally jacked it in at 4.00am having achieved the target, 19 bridges in all!

Each bridge is checked carefully for roosting birds, usually on ledges, but they can be hidden away in old nests, cracks or drainpipes. A record is made of the total number of birds present (normally only one or two but I have had up to 11 birds under one bridge!) I've been doing these annual roost counts at many of the sites since the mid 1980s and they're proving to be a very useful population indicator. In addition to the count, we obviously try to catch all birds for ringing. Last night a total of 26 birds were found and 24 were caught, not 100% I'll grant you but not a bad result in anyones books!  Retraps and controls usually form a high proportion of all those birds caught and last night was no exception. Of the 24 caught, 7 were new (1 adult and 6 juvs), 14 were retraps from previous years and 3 were retraps of birds ringed as nestlings earlier this year. Our colour-ringing project also  took a major leap forward. As we only started fitting colour-rings in April this year, and don't colour-ring nestlings, only 2 of the birds were already marked so 22 new colour-marked Dippers resulted from the night's activities.

All in all a brilliant start, well, up until the moment my foot slipped off a wet metal rail just as I was straddling the side of a bridge - I suddenly became half my normal height, wet around the eyes and very vocal!

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