Oystercatchers

My 1st SCAN canon netting trip of the year took place a couple of weeks ago in Bangor harbour where we set a net to catch roosting Oystercatchers at dawn.

A combination of bad luck and flighty birds (a Peregrine chasing Knot didn't help the situation) meant we didn't catch as many as we'd hoped. With a big team having a small catch was certainly more relaxed and gave time for the newcomers to discuss the ageing and sexing characteristics as will as looking at some odd moult.

The oldest bird caught was ringed in October 2005 making it nearly 20 years old. It was aged on eye colour as Euring 8 meaning we know it was definitely hatched 3 or more years ago.

An adult Oystercatcher would have been expected to have completed its post breeding moult last autumn but this bird still had unmoulted outer primaries and inner secondaries on both wings. Maybe a sign of advancing age (the bird was later found to be ringed as an adult 19 years ago) or maybe an unexplained arrested moult.

Another ageing feature for Oystercatcher is leg colour with older birds having pinker legs whilst young birds are much duller.

Euring 5 birds (born last year) are identifiable by their dull brown eye and may have some retained brown juvenile feathers as in the photos below: