Monday, 19 September 2011

Fog on Tour

Hi all,

Sorry it has been a while since an update but couple of things have been going on in life recently so haven't written up my blog posts.

I will start off by showing some images of a local juvenile Black Guillemot, some of you may remember a week or so ago I wrote a blog post mentioning it as I saw the bird at Hartlepool. It has stuck around and has been going about its business and sometimes it seems to be coming within a fairly decent range to allow some photographs to me taken:

(Black Guillemot - © Ian Forrest)

Yesterday I was planning to go to Whitburn Obs on the morning as the winds looked favourable and I thought there might be a chance of Great Shearwater, however my plans were thrown out the window when an American Black Tern turned up and was ID'd in Lincolnshire. I had not a clue how to separate the form from the British form (niger) so a brush up was needed on the Saturday evening. It was a hard 3hour drive on my own but I eventually arrived on site about 12:15. I had received a message to say the bird had flown off West......thankfully it was still sitting in the ploughed field with the local Black-headed Gulls. The bird showed very well and I enjoyed watching it for about 20-30 mins before leaving for the long drive home. It was a very educating and interesting bird, it was expensive to get there and back however this sort of bird interests me a lot. The chances are the bird will not be split and I won't get my BOU 'tick', but I have put it down on my own personal list. The birds (surinamensis) in juvenile plumage is certainly identifiable from "our Black Terns" (niger).

Features I noted in the field to separate from niger:
  • Tones on crown and nape are greyish in tone on surinamensis and this contrasts with the black ear coverts. On niger the marking on the crown and nape are uniform with the ear coverts, often very little difference is shown.
  • The upperwing was fairly uniform grey, quite a dark grey opposed to the paler grey on niger, which tends to show a fairly contrasting light rump.
  • The underwing is very different, in niger the underwing is white whereas it is grey in surinamensis. Additionally the axillaries and flanks have a greyish wash to them in surinamensis, however in niger the axillaries and flanks are white not washed grey. 
There are other features but I didn't necessarily notice these much in the field, a very educational and interesting bird. A one to look out for with the next Black Terns in Durham and further afield. 

Some of the features I noted above can be seen in this photo kindly supplied to me by Dean Eades, Dean's website can be accessed by CLICKING HERE.

(American Black Tern - © Dean Eades)

Until next time, Foghorn out!

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