Following the interesting post on a summering Pallid Harrier (Circus macrourus) on the Netherlands by Nils, I thought sharing these photos of a quite Pallid-like juvenile Montagu´s Harrier (Circus pygargus) could be of interest.
The bird was seen near Zaragoza, Aragón, Eastern Spain, in mid September, and had been ringed and wing-tagged in France this past summer.
As you can see on the pics, the head pattern of this juvenile was quite striking and well marked. If not seen well, It could resemble that of a Pallid Harrier to the inexperienced observer.
The prominent pale neck collar was almost complete, the hind neck was very dark and contrasted a lot with the pale collar, the white areas around the eye were relatively small and the lores were quite dark. Thus, quite Pallid-like if seen distantly.
However, on closer inspection, you can see that the pale collar has some faint dark smudges (which could easily go unnoticed if not seen close, though), the dark hindneck is not uniform, but shows some paler spots mixed in with the dark feathers and the dark cheek-patch only reaches the gape. All these features would identify the bird as a well-marked juvenile Montagu´s, but would require good views.
Furthermore, the primary pattern is also typical of Montagu´s. Unlike most Pallids, the bird shows almost all dark fingers and obvious dark tips to the inner primaries. Beware of the last feature though, as some Pallids can also show contrasting dark tips to the inner primaries, like Montagu´s.
The barring of the primaries, although relatively extensive, is finer than that of a typical juvenile Pallid.
Several fine streaks are present on the upper breast and flanks, which should be absent on juvenile Pallids in autumn.
All in all, an interesting bird that addresses the need of good views and a proper study of the primaries, amongst other things, when confronted with any pale-collared juvenile Harrier.
Many thanks to the photographer, A. Manuel Galán Subias, for letting me use his photos on the post, and also to Javier Train for first sending them to me.