Pallid Harrier: Next step in status change

First-summer male undertakes post-juvenile moult in the Netherlands.

by Nils

Well within the time of my birding life, Pallid Harrier was nothing less than a mythical species. Nowadays it is much less rare in NW Europe (in the Netherlands we can call it a rare to even scarce migrant now); but still today, many birders will get a magic feel when they see a Pallid Harrier. In Dutch language the species is named ‘Steppe Harrier’, which further add to the magic (and because I know MG likes it: exactly translated Steppe Chickenthief). It makes me still dream away to its formerly normal range of vast steppes in ‘far eastern’ countries. But it also is just a wonderful bird!

The recent high numbers in Europe are unlikely explained alone by the increasing knowledge of the immature and adult female plumage’s, or by the now many, almost daily occupied migrations watching points either. Although naturally these factors have add to the overall picture, the species must be really much more common today (in western Europe) than a decade and more ago; going through a remarkable rapid status change.

In the Netherlands the spring of 2012 shows just the expected pattern with several 10s of records of mainly migrating individuals. The first individuals typically start to appear from the beginning of April (so, much earlier than Montagu’s).  The settling down of a male that starts his first complete moult was again a new phenomena in the row and gives us the nice opportunity to follow the progress of the chancing plumage.

The bird was found on the 6th of May and stayed mostly in agriculture fields in the county Drenthe until at least the end of August.

As usual in 2nd cy spring Pallid Harrier, in the beginning the bird was very juvenile like. Only some dark streaks on the crop-area betray the first signs of post-juv moult, possible acquired in an earlier stage. The pale iris immediately confirm it’s a male.

13 May (photo by Gerard Sterk)

On or just before 20 May the complete moult really started; both p1 were dropped and on 26 May p2 on the right side. From then the primary moult takes a sprint with up to p5 dropped on 5 June. Also many greater upperwing coverts were dropped, but no underwing coverts.

5 June (photo by Claudia Burger)

Until 14 June no extra primaries were dropped but p1-p5 were more than half grown.

21 June: p1-p5 are fully grown (being typically uniform blue-grey unlike any other harrier at this stage); the body and underwing coverts were still unchanged, but the greater upperwing coverts were replaced (greyish; not visible in this picture). (photo by André Strootman).

26 June: new brown-greyish scaps and tertials appear.

11 July: the first secundaries are replaced (looks like s3-4), the head and underparts are moulted (crop-area again?). Now the breast and flank are quite extensively dark streaked, maybe surprisingly for a male! The axillaries and median underwing-cov looks still juv-type. The primary moult way have reached p8 (which is dropped), p9-10 are still juv-type. (photo by Claudia Burger)
6 Aug: juv p10 is still present, p9 is dropped. The underwing coverts and axillaries are almost fully moulted, the dark central secundaries are still juv-type. (photo by Michel Linnemann)

On 22 Aug, the last day that the bird was photographed so far, there seemed no juv secundaries left and the new p10 was growing. So, with the last stage under way this fine bird will likely be gone soon.

Interestingly, this male shows more dark pattering of the underparts than normal in 2nd male after the complete post-juv moult, but it is far from unusual.

Many thanks to Frank Neijts and especially Vincent Hart and of the administrator-team of www.waarneming.nl for their great help in sorting out all the pictures and making contact with the photographers, who are also greatly thanked!

2 thoughts on “Pallid Harrier: Next step in status change

  1. Albert J. de Jong

    Ah, nice post, Nils! I had the plan to write a short note for the DB journal……..I think it would still be interesting to describe the molt sequence as precise as possible, because I couldn’t find a lot about it (2cy) in the literatrue s o far.

    Reply

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