Ringing Report 22nd September

After a what seems like weeks of westerlies, the wind swung north/north east resulting in a promising window of easterlies, the first real ones of the autumn. The plan, ring on the Saturday, work the scrub on the Sunday. Saturday resulted in approximately 50 new birds, which included blackcap, goldcrest, chaffinch, bullfinch, greenfinch, linnet, goldfinch, blue tit, coal tit, great tit, dunnock, robin, chiffchaff and a single brambling. Certainly a productive session, which also recorded wheatear, house martin, grey plover and brambling overhead. In addition at least two yellow-browed warblers were recorded around Filey, unfortunately being unable to leave the ringing site I was unable to connect with either.

The brambling (seen above), was a 1st winter female. Brambling are a close relative of the more familiar chaffinch, and predominantly visit Britain during the winter, although breeding is occasionally recorded here. Brambling tend to breed in a broad strip in northern Europe, from Scandinavia to Russia. Brambling are closely associated with beechmast, and areas rich in this can be good places to look throughout the winter. Studies have shown that they stay as far north as the availability of beechmast allows and as snow increases they push further south. The first brambling begin to make landfall around mid-September, like this bird. The key arrival period occurs through October until November. Unlike Chaffinch brambling predominantly migrate at night.  

The other bird at note was coal tit (c.15 of them). All coal tits trapped today, were 1st winter birds. This continues the theory, with regards to local populations, in that young birds leave the natal area during the autumn. In this region the core populations occur in the forests on the southern edge of the North York Moors (Dalby, Cropton, Wykeham et al). Coal tits typically select coniferous woodland to breed in, and tend to have greater breeding productivity in such habitats. Coal tits are well adapted to this habitat, with characteristics like the foot (long toes and claws, not opposable, unlike Blue Tit) and fine bill for foraging for small food items, especially in conifers. Coal tits are typically quite a sedentary species in Britain, although they do make small scale movements such as these irruptions. The exact advantage (if there is one) of leaving the coniferous forest they are adapted for, and in which they have an edge on rival species like blue tit, is largely unknown. Perhaps this is a form of juvenile dispersal to seek new breeding grounds, adults remain in closer proximity to breeding territory, or not enough resources occur in the forest to support young subordinate birds. However the species is more than capable of surviving harsh winters in conifer woodland, using techniques like food caching and the population which remains appears to be dominated by adults (2nd winter). Coal tits have been recorded crossing the sea to Britain from Scandinavia, which raises another possibility.