Thursday, 15 December 2011

Pallid Harrier (Circus macrourus), Aguilucho papialbo, December 2011

Pallid Harrier (Circus macrourus)

There are at least five Pallid Harriers, Aguilucho papialbo (Circus macrourus), in and around the La Janda area at present. I have noted three individual juveniles and two adults - this adult female (above) and an adult male. I haven't seen the adult male for two days but then I couldn't access a large area for a couple of days where he's been regularly hunting.

Identification confusion between similar looking species
ie. Hen Harrier and Montagu's Harrier

1. Adult female Hen Harrier (Circus cyaneus)

2. Adult female Montagu's Harrier (Circus pygargus), again for comparison.

Please refer to these when I talk about plumage or other diffrences between all three (ring-tail) harriers. I tried to look out and show underwing views which will help with identification.

Back to the adult female Pallid Harrier
Pallid Harrier (Circus macrourus)

I think that the sunlight gives the bird a slight tinge, which threw me at first but you can see that this bird has all the diagnostic markings of an adult - probably fledged in 2009 or perhaps earlier. As ever, I'm open to suggestions or comment on aging. These are new birds for me and a lot of others as well and each time we get a chance to watch them or look at any worthwile photos, we gain little bits of additional information which makes identification in the field a little bit more confident and slightly easier

Pallid Harrier (Circus macrourus)

Female and immature harriers are tricky to identify. Let's have a look at comparative birds and where differences between these are apparent.
The Pallid female is a little bit more muscular looking and seems to be a stronger flier than say an adult Montagu's Harrier. It also doesn't have the bounce in the flight as in Monty's and looks more like a Hen Harrier. It can also move very quickly in a straight line with powerful, businesslike wingbeats.

Pallid Harrier (Circus macrourus)

The underwing markings of an adult Pallid may look like a female Hen but like the Monty's, Pallid has a slimmer wing and only four primary feathers, 'fingers' showing at the end of the wing or 'hand'.

Pallid Harrier (Circus macrourus)

Distant views out in the field with shadow as in the very top photo, may give the impression that the greater wing coverts and the secondary feathers appear to be quite dark, probably more so with juveniles. On closer inspection (isn't it great to have the digital photo age), you can see three darker bars running roughly in the secondaries to the armpit.
With the Pallid the inner two bars are narrower and less prominent on the terminal band than with Hen and Monty's which remains broader at the armpit. Both Monty's and Hen adult females have broader, bolder looking white-grey spacing between the brown barring on the underwing.
Female adult Hen Harrier has less white around the eye as here with the adult Pallid and the neck ring is just that little bit lighter but not always so easy to compare in the field.

On now to one of the other birds, the juvenile Pallid Harrier (below)

Underneath are a few photos of one of the juveniles I photographed a few days ago. Unfortunately I didn't manage to get closer, managing only a quck burst of flight shots. I have some more but it was in a very fast glide through a wooded area and these are the better ones

Juvenile Pallid Harrier with that very noticable collar or neck ring, some field guides refer to this as a 'boa'. Juveniles are much more rusty-ochre coloured and Juvenile Montagu's Harriers seem even brighter with no white neck ring. The undersides are paler in contrast to the juvenile Monty's darker appearance. The best indicator would be to look at the collar marking.

More news as it happens. Thanks for dropping by, Stephen
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