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Pomarine or Parasitic Jaeger? (2 Viewers)

Mark B Bartosik

Well-known member
Several days ago juvenile jaeger has shown up on beach near west end of Galveston Island in Texas. From my observation it had some problems with one of its legs (seems temporally) and also has missing tip of its left wing (few primaries are missing). Bird can fly very well. As typical pelagic species jaegers very rarely can be found on land. Now is big debate; some birders say it is pomarine some parasitic.

I can only hope that my question will bring some experts to this thread to clarify the right name for this bird.

Also as opportunity to get so close portraits of jaegers is rare (I was even getting headshots from about 8 feet) it is a perfect moment for nature photographers living in close range to get some jaeger’s photos.

In posted photos I am trying to present all angles showing important field marks areas, but if some more details are needed, please point it to me and I should have it on another photos.

My own opinion: many field marks lead to say parasitic. But from my past life I never trust field guides 100% as I do not trust field observations as well. I always preferred to have specimen in my hand for all necessary analysis and comparison. Also as I never had opportunities to see and compare specimens of those two species I can not say if an expert can or cannot separate them with 100% certainty in the field.

Thanks for the time of those who are willing to help. If someone is interested in pinpoint location to find this bird I will send him/her this information. Of course I cannot guarantee how long this bird is going to be on shore.

Best regards, Mark

Folder:
http://www.photo.net/photodb/folder?folder_id=538934

or direct links to photos:
http://www.photo.net/photodb/photo?photo_id=3830837

http://www.photo.net/photodb/photo?photo_id=3830836

http://www.photo.net/photodb/photo?photo_id=3830835

http://www.photo.net/photodb/photo?photo_id=3830832

http://www.photo.net/photodb/photo?photo_id=3830831
 
Man... what a beautiful bird. If I had to guess between the two, I'd say parasitic. Jaegers are certainly not birds I know a lot about, however, so I'll leave it to the experts. I'm very interested to see what the verdict is.
 
I can see why there is debate. Strcuture, and bill on first glance said Parasitic to me. However - the white bases to the underside of the Primary coverts and the shape of central tail feathers is 100% Pomarine. The strength of the barring on the rump and vent and the belly heavy look in the first pic also support Pom.


I need longer on this than I have - but current guess is underweight small Pom.
 

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Tough one - first instinct on opening the pics was parasitic purely on structure, body and bill look to slight for pom. However on closer inspection the features that Jane has pointed out - the barring on the rump and the pale area under the wing - look good for pom. I also think that the white on the upperside of the wing, the way it extends along the primaries, looks good for pom. I would expect this to be a more defined 'white flash' on parasitic - though clearly that's a bit subjective.
 
Jane has said exactly what I was going to post!
For me its definatley a Pomarine for the same reaons Jane says, white under primary coverts and the quite obvious barring on the tail/rump area of the bird.
However, the close up head shot looks very Arctic/Parasitic bacause of the colouration- looks quite warm brown (which is a side effect of the light i beleive, and also bill structure). Aside from that I am sure that this is Pom!

Regards,
Rob
 
Makes you think doesn't it. We struggle to be sure of the ID even with very good pictures but people happily ID these two species when they're miles out to sea and the visibility is really bad.

I think it's probably a Pom btw.
 
Agree with Jane and the features she mentions. Pomarine Skua for me too. Check out that bill - too stout for any normal Arctic Skua.

Rgds

Greg
 
Have you got a picture of the underwing with the wing strecthed out. A really good feature for Poms (which I think this is) is the double hand. The structure of this bird screams out Pom as well very heavy chested stout neck rounded head bill looks too chunky for Parasitic. Really nice pictures Mark.
 
Closeup of the head shows no streaking, more like diffusely spotted as on Pomarine.
Face usually darker in PS. There seems to be a hint of a pale neck band on the two pic of the flying bird, and with lifted wings. Juvenile PS don´t show an obvious pale neck, and if do, the whole head is pale. Otherwise agree with Pomarine ID, but sometimes like them better at a distance.
JanJ
Nice images!
 
The under primary coverts ( I hope this is the correct designation in English) have a light base. It is a Pomarin for sure.
 

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Andrew Whitehouse said:
Makes you think doesn't it. We struggle to be sure of the ID even with very good pictures but people happily ID these two species when they're miles out to sea and the visibility is really bad.

I think it's probably a Pom btw.
Andrew,
That's because they are easier at range than they are like this. You just don't tend to see Skuas sat so close very often. Inland Long tails almost always cause problems when they turn up on golf courses etc. but are in fact pretty easy to i.d the vast majority of the time when at sea.

G
 
Some Parasitic shows a pale base to under primary covert base, one 1 out of 20 according to Collins.
The PC-base patch in Pom. is apparently more obvious in light-type than in intermediate and dark typ plumages. Although described as a good species character, it´s sometimes hard to see, if not seen well, I think.
BTW, very good images! Check his webb site!
JanJ
 
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