The weather conditions were ideal for bird ringing this morning, flat calm, slightly overcast and as a bonus there was no frost!! We started early and had all the nets open by 6:30, and waited in eager anticipation.......and waited.....and waited! There was plenty of bird song in the air, with Song Thrush, Blackbird and Dunnocks all proclaiming their territories, and a mixed flock of about 100 Redwing and Fieldfare, but other than that there were very few birds around. But still we persevered and soon started to catch a few birds, two Robins, three blackbirds, a single Greenfinch and the usual Blue and Great Tits made up the bulk of the birds, and eight House Sparrows added to the information for my RAS project. My favourite bird of the day though was a Eurasian Treecreeper.
I have written about this species a couple of times before, and as they are such stunning little birds I thought that I would write about them again. There are two species of Treecreeper in the Western Palearctic, Eurasian and Short-toed, but it is only the Eurasian Treecreeper that is resident to the UK, therefore the likelihood of catching the a Short-toed is slim, nevertheless it is always worth checking!
It can be difficult to separate the two species since the plumage differences are slight and the biometrics overlap, but in most cases it is usually possible to easily identify a bird using a combination of features. Firstly, in Eurasian Treecreeper the lower edge of the prominent wingbar is more square edged or rounded, with a large and prominent pale spot forming the end of the wingbar on the fourth primary. In Short-toed the lower edge of the wingbar is more pointed and the spot on the fourth primary is either very small or even absent.
In addition the hind claw of Eurasian measures between 7.6 - 11.5mm, whereas it measures between 6.8 - 8.9mm in Short-toed. The hind claw on this bird was very long and well outside the range for Short-toed.
|Long claws for gripping the bark of trees|
So putting all the features together, this bird was clearly a Eurasian Treecreeper.
|Fine and pointed tool, ideal for locating food in the crevices in bark|
In evolutionary terms Treecreepers are amazing, they have been perfectly designed to climb up the trunk of a tree, usually starting low down and working up to the spindly twigs at the top. The bill is long and thin and ideal for teasing out food from small crevices....
|Rigid spiked tail....a third leg!|
...........and the rigid and spiny tail is used to rest against the trunk of a tree, providing extra support and acting as a third leg.
They are tiny birds, weighing around 8.0 grams, and their mottled brown colouration provides excellent camouflage, which is why the are probably heard more often than seen.