Scapular age
Posted: Sat May 26, 2018 1:58 pm
Hi!
David Erterius wrote this on FB regarding a 2cy Caspian Gull.
"Just wanna discuss the appearance of many second calendar year Caspian Gulls occuring by mid-late spring here in southern Sweden. To illustrate this, here's an example from Simrishamn, Scania 6 May 2018.
As far as I can judge, this bird exhibits two different types of scapulars, hereafter referred to as "a" and "b".
a) To me, these must be second generation post-juvenile feathers with the typical anchor-pattern on some of the least worn feathers.
b) These feathers are marked differently with prominent shaft streaks and lacking the distinctive "anchors". The lower row of these types consists of less abraded scapulars, as what can be expected due to the more sheltered position. However, the upper group shows a similar wear as the a-group, hence I'm assuming all these b-group feathers were moulted in the same sequence as the a-group or soon after. Alternatively, these are third generation feathers which has been replaced at a later stage.
These are just my thoughts and I might be wrong so please feel free to elaborate on this and share your own thoughts."
I had them as 2gen, but my brain got blury so what´s your opinion?
Jan
David Erterius wrote this on FB regarding a 2cy Caspian Gull.
"Just wanna discuss the appearance of many second calendar year Caspian Gulls occuring by mid-late spring here in southern Sweden. To illustrate this, here's an example from Simrishamn, Scania 6 May 2018.
As far as I can judge, this bird exhibits two different types of scapulars, hereafter referred to as "a" and "b".
a) To me, these must be second generation post-juvenile feathers with the typical anchor-pattern on some of the least worn feathers.
b) These feathers are marked differently with prominent shaft streaks and lacking the distinctive "anchors". The lower row of these types consists of less abraded scapulars, as what can be expected due to the more sheltered position. However, the upper group shows a similar wear as the a-group, hence I'm assuming all these b-group feathers were moulted in the same sequence as the a-group or soon after. Alternatively, these are third generation feathers which has been replaced at a later stage.
These are just my thoughts and I might be wrong so please feel free to elaborate on this and share your own thoughts."
I had them as 2gen, but my brain got blury so what´s your opinion?
Jan