Monday, 13 August 2012

Estuary Polish

This colour-ringed Caspian Gull has been seen previously elsewhere along the Thames when a first-winter.
Note the extent of primary moult by mid-August, and lingering signs of immaturity including bill markings.

After the spectacular natural beauty of Maine, today was a scenic reality check of epic proportions. As much as I love birding on the Thames Estuary, it can't rival the splendour of the New England coastline. In particularly stark contrast was today's visit to my gull study site, where dry and dusty conditions made for even more filthy birding than usual. Compensation came in the form of this Polish-ringed Caspian Gull (above), an individual I haven't seen previously. The combination of posture and head/bill shape initially made me think it could be atypical, and knowing Polish birds are often from mixed colonies I wondered if it might have mixed genes. But early feedback from Polish ringers and photographic evidence of it as a first-winter suggest otherwise. It's now my third Caspian from that country - providing clear evidence of where some (most?) of our birds originate. It was one of two present, the other being an unringed first-summer bird.

One of several first-summer Yellow-legged Gulls today. Birds of this age are often distinctive.
Also noted today were 35 Yellow-legged Gulls (all ages, one metal-ringed bird), large numbers of Herring and Lesser Black-backed Gulls (the latter including a Dutch colour-marked adult and several intermedius types), even more Black-headed Gulls, but fewer than 10 Great Black-backed Gulls and no Common Gulls (though I have been seeing a few of the latter on the river itself since the first birds returned last month).

Adult Yellow-legged Gull. The Thames Estuary is one of the best sites for the species in late summer.

No comments:

Post a Comment


Related Posts Plugin for WordPress, Blogger...