Sunday, 5 June 2016

Crawford: 4th June 2016

I resumed baiting the farmland site at Crawford recently as it can attract good numbers of juvenile Tree Sparrows in the period just before the first crops of winter cereals start to ripen. It is also a good site for Goldfinches and catching adults at this time of year allows me to confirm their sex by the presence of a brood patch or a cloacal protuberance. Sexing Goldfinches from their plumage characters is a long standing interest of mine but I am also interested to see if there is much, if any, change in their appearance as birds age. This site gives me the best chance of retrapping known sex adults that I have photographed in previous breeding seasons.

Another reason I like baiting this site at this time of year is that I don't have to get up at daft o'clock to get a good catch so I only set the first alarm for 5am and eventually set off just after 6. The drive to the site is usually uneventful but I hadn't gone far before I encountered a Woodpigeon that was suicidal or playing a game of chicken very badly. I slowed right down and nearly had to stop such was its ambition to become another avian road casualty. It wasn't the only one and every few hundred metres there were Woodpigeons in the road, presumably all taking grit, and it wasn't long before I came across a freshly exploded Woodpigeon lying in a wide halo of body feathers. However the most unusual sighting along the route was Roe Deer as it was the first I had seen in that area. At least it showed some road sense and went back through the hedge on my approach.

On getting to the site I was greeted by the calls of Tree Sparrows and it didn't take long to set up a couple of nets in a line by the hedge and feeders. The first net round produced 7 Tree Sparrows, 2 Great Tits and a Chaffinch with only one of the Great Tits being a retrap. In between some of the quieter net rounds I checked out some of the adjacent fields and it was nice to have 3 Corn Buntings singing in the usual spots and the recent large influx if Diamond-back Moths was much in evidence with dozens being disturbed along every few metres of some of the field margins.

Diamond-back Moth

Reports from the south and east coast suggest that many millions of these tiny migratory moths have come into the country in the past few days with upper estimates in the low millions coming from the recording areas of just two two coastal observatories.

11 of the 13 Tree Sparrows caught were juveniles like this bird.
Adult Tree Sparrow
I packed up at at 10am having caught 29 new birds and 2 retraps. Species totals (retraps in brackets) were: Tree Sparrow 13, Greenfinch 6; Chaffinch 4; Goldfinch 2; Whitethroat 2; Robin 1; Great Tit 1 (2).

I was disappointed that I only caught 2 Goldfinches on this visit but every adult caught at this time of year adds to my collection of photographs of known sex birds and my understanding of the variation the sexes can display. As you can see the red on the face of this bird doesn't extend very far behind the eye but blowing back the feathers of the vent confirmed it was a male.
The lesser coverts of the same bird had narrow and well defined brown fringes which is typical of many males.

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