13 Feb 2009

1 Feb 1989 - Bird ringing

The storms have passed leaving us with fairly clear sunny weather again. Peter has the mist nets up in the area where we watched for hawfinches yesterday ‑ he hopes to net one so that we can see it close up. When a single bird flies off, he is fairly certain its mate has been caught as they are usually seen in pairs.

Having caught the bird, Peter is very careful in handling it ‑ the huge bull designed for crack­ing cherry stones was quite capable of exerting the same pressure on human fingers or anything else that came close enough. This individual is a female, indicated by the greyish edges to her secondaries, which have a short blocky shape pecu­liar to hawfinches. She gets her revenge ‑ manag­ing to bite Peter's finger as he releases her ‑ then she sits and sulks in a nearby tree for a while.

There is a variety of birds in the mist nets, and Peter again explains things about plum­age that can be seen only with a bird in the hand. In northern Europe juvenile passerines undergo a partial moult in the autumn and through their first winter are distinguishable from the adults by their juvenile flight feathers. How­ever, in the warmer south, the young birds have a complete moult in the autumn so that it can be difficult for ringers to age them with any certainty. Peter shows us several birds that have retained just a few primary or tail feathers, or primary coverts from their juvenile plumage. Other birds show abrasion of the white tips of the flight feathers so that the ends looked distorted ‑ extreme cases were probably southern birds, as the strong sun weakens the feathers.

In the field it is usually difficult to see the colour patterns on individual feathers and therefore to appreciate just how the overall markings are made up. In the goldfinch, for example, the golden wing-patch is not formed by solid yellow marks right across the flight feathers, but by the outer edges of the feathers having a yellow stripe. The inner part of the feather is pale. On the female greenfinch the relatively pale primary panel is formed again by a yellow strip on the outer edges of the feathers while the male's brighter panel is formed by the yellow strip extending to the feather shaft.

I spend the afternoon in a hide hoping to photo­graph some small birds but without success. Jim walks out along the east marsh and returns with tales of an adult spoonbill and an eagle. He took detailed notes of the latter ‑ ginger head with white marks on either side, white belly and under­wing coverts, dark flight feathers, brownish mantle and scapulars, extensive black on tail, white rump etc ‑ after waiting so long to see an eagle he wanted to be able to identify it proper­ly. It was, in fact, a pale-phase booted eagle. A few of these winter in southern Portugal, or perhaps it was a migrant returning from Africa.

Walking through the vineyard this even­ing, we flush two quail - close enough to see their stripes. One flies into a barbed wire fence in its haste, hopefully it is not badly hurt for it continues on its way with a whir of wings. Our sojourn is made to the accompaniment of mole crickets and marsh frogs.

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