Saturday, 6 December 2014

Crawford - 6th December 2014

It has been quite a while since I have done any ringing at the farmland site at Crawford, near Upholland but an afternoon visit a few days ago revealed a good number of thrushes feeding in the hedges. The hawthorns at the site still have a good crop of berries but they may not last for much longer if we get a few frosts and the birds are forced to feed on them even more. I also dropped off a few apples that I had brought along with me with a view to attracting the birds to the hawthorns by the net rides. 

I returned early this morning and set up a couple of nets just as it was coming light. I wasn't sure how many birds would turn up but I didn't have to wait long before the first small flocks of Redwings and Fieldfares arrived through the gloom. It turned out to be a very productive session considering I was only using a 12m and 18m net with the majority of birds being caught in the first couple of hours.


The Redwings frequently gathered in a large willow before dropping down to the hawthorns to feed.
Take off
The 21 Redwings ringed today brought the total for this autumn/winter to 741.
One of the three Fieldfare caught this morning.
This cracking adult male Blackbird was almost certainly a continental bird given its wing length of 142mm. Blackbirds from the more sedentary British population typically have a much shorter wing length.
It also had a good sized bill.
While thrushes made up the bulk of the catch some additional interest was provided by a few Greenfinches including 2 controls (birds ringed elsewhere), a Willow Tit, a Tree Sparrow and a Yellowhammer. The Willow Tit was unexpected as the site doesn't really have enough suitable habitat for the species. I have caught one there previously (post here) but that was in June when the juveniles are dispersing and can often be found well away from their usual haunts.


Willow Tit 06/12/14
The Willow Tit had a pale spot along the cutting edge of  the upper mandible below the nostril and this can be seen in both photographs. This is usually a feature of Marsh Tits but a small proportion of Willow Tits (around 4%) can also display a similar pale spot. Interestingly the only other Willow Tit caught at this site also had an almost identical pale spot. Perhaps they are related in some way and they could even be siblings if such features are inherited; pure speculation of course but it seems to be a bit too much of a coincidence given so few Willow Tits display this feature. Richard Broughton's paper on separating Willow and Marsh Tits can be found here.

Ringing totals for 06/12/14 were: Redwing 21; Fieldfare 3; Blackbird 4; Robin 1; Blue Tit 1; Willow Tit 1; Greenfinch 6 (+2 controls); Tree Sparrow 1; Yellowhammer 1. Total 38 new birds and 2 controls.


Tree Sparrow

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