Immature Great or Christmas Island Frigatebird? (1 Viewer)

[Hor Kee]

Dear all,

During a pelagic trip from a working anchovy purse seiner yesterday, I had the fortune of seeing my first two Frigatebirds ever. One was an obvious nearly-adult male Lesser Frigatebird. It was accompanied by this much larger bird which was about 30% larger.

Opinions from my birding community so far are split between a juvenile of either Christmas Island or Great (both are of similar size), and trend more towards the latter.

Factors in favour of the Great are the following:
(1) The lack of auxiliary white spurs to the white belly patch (the white 'armpits');
(2) The more squarish rather than hexagonal shape of the white belly patch;
(3) Proportionately slightly shorter bill than the CI.

The main factor in favour of the CI frigatebird is the complete black breast-bar. However it appears that Great juveniles also have this feature as per the shots on OBI.

Sadly, David James's excellent article on the "Identification of Christmas Island, Great and Lesser Frigatebirds" is no longer available online on the OBI website.

Feedback is greatly appreciated!

Thank you.

Cheers,

Hor KeeB

 

[Andy Adcock]

Can't reason why, this is a tricky one but I'd go for Great even though it's by far, the less common in the area......

Andy

 

[Hor Kee]

Thanks Andy. You're right that it is rare record. In fact, it could be the first confirmed record from the Straits of Malacca in decades, so all the more important that it is confirmed to be a Great rather than Christmas Island. May i know the reasons why you think that it is a Great please? Thank you once more

 

[njlarsen]

I would go the other way. Within the last month I visited Galapagos where we saw a good number of Great Frigatebirds. In the juvenile age, white lower breast is in direct contact with yellow/orange/tawny head. We were told that some older juveniles was an id problem relative to Magnificent because the tinge on head and upper breast might fade to the extent that the entire area was white. This bird has a black area between white breast and tinted head that just does not fit.

Disclaimer: I do not know if Great can look different in other parts of the world.

Niels

 

[Hor Kee]

Thanks Niels. The main confusion species for Great here in South-East Asia is the Christmas Island Frigatebird which is of similar size and build - we don't have Magnificents. As far as juveniles of this age are concerned, apparently the CIF has a hexagonal white belly patch, meaning that the portion in the center of the breast band is horizontal. And the CIF has (in 95% of the individuals) the white 'armpits' or auxiliary spurs that extend from the white belly patch to the 'armpits' of the bird, which was not present in the above individual. CIF apparently has much more extensive white/light buff upperwing covets compared to this one and a proportionately even longer bill. I have no idea as to variations at the subspecies level though, but the ones found in my area are the nominate F. m. minor.

One of my friends did point out the extent of the black breast band but apparently this is not so much a defining feature as juveniles of both GF and CIF can sport this feature as seen in the following links:

CIF:http://orientalbirdimages.org/birdi...D=1175&Bird_Image_ID=30986&Bird_Family_ID=125

GF: http://orientalbirdimages.org/search.php?Bird_ID=1173&Bird_Image_ID=38147&p=5

The difference in the shape of the white belly can also be seen in the above two pics.

Thanks for your feedback sir!

 

[njlarsen]

Before my previous answer, I did not go to my Australian bird book. That seemed to confirm the impression I got from the two images you linked to, that CIF seems more likely, but I will want to register the disclaimer that I am not familiar with the birds in your neck of the world.

Niels

 

[Larry Sweetland]

Not sure where it is, but there's a very good in depth (and for me very eye-openning) id guide to frigatebirds on the net. Worth finding it if you haven't seen it Hor Kee.

 

[Andy Adcock]

I've spent a combined total of about 2 years in this area and never seen Great......or have I?

If they are so tricky on an image such as this, any and all records without supporting photos should be treated with extreme caution.


Andy

 

[Larry Sweetland]

I've spent a combined total of about 2 years in this area and never seen Great......or have I?

If they are so tricky on an image such as this, any and all records without supporting photos should be treated with extreme caution.


Andy

I think, having read the id article that I refered to above, that the main problem has been that the field guides don't tell you how to identify them correctly in all plumages. Can't recall the details, but I came away from reading it realising that I almost certainly hadn't seen CIF (it being in all likelihood a Greater). I'd be very surprised if the OP bird can't be identified from the article with those images.

 

[Larry Sweetland]

drat, found a link to the article in two other frigatebird id threads: http://tanzaniabirds.net/articles/Fr...irdingAsia.pdf but the link doesn't seem to work any more.

 

[njlarsen]

Is this part of it? http://www.tanzaniabirds.net/African_birds/frigatebird_greater/gf.htm

Niels

 

[Larry Sweetland]

Is this part of it? http://www.tanzaniabirds.net/African_birds/frigatebird_greater/gf.htm

Niels

Doesn't ring any bells as being the same one Niels. It was specifically how to id Greater, Lesser and Christmas I frigatebirds at all ages, with chat about plumage progression.

 

[njlarsen]

The origin of that article seems to have been http://orientalbirdclub.org/birdingasia-1/ - where it is not part of the freely available articles.

Niels

Edit: it can still be found using one of the search engines for internet pages that no longer exists.

 

[Hor Kee]

Ive tried repeatedly but its no longer available

 

[Hor Kee]

Dear all,

Once again thank you very much for your feedback. I have managed to get my hands upon the article by David James - thanks to those who have sent it to me. What a difference it made!

My opinion is that this is a juvenile Great Frigatebird. The key feature in distinguishing this species from the juvenile CIF is the shape of the white belly patch and the auxiliary spurs which I shall refer to as the 'white armpits'.

The 'problem' with my bird is that it appears to have very short white armpits - so short that they cause the shape of the belly patch to deviate from the traditional egg-shape of the GF into a more 'diamond' shape reminiscent of a CIF (which is actually hexagonal, but more of that later).

Most GF juveniles lack white armpits, and identification should be quite straightforward in such circumstances. See, for instance, https://leesbirdblog.files.wordpres...egata-minor-palmerstoni-juvenile-by-ian-5.jpg.

On the opposite extreme end of the variability spectrum, the minority of GFs that that do have the white armpits have them emerging from the center of the white belly patch (the 'midriff' of the egg-shaped white patch). This will result in a diamond with two 'wings' right in the middle as can be seen in this bird taken by one Smew Mao from Hong Kong https://www.dropbox.com/sh/vi57b403glya8ks/AABHKsUAQ4-2Ik67cAiHoqpLa/D8E_9069-2.jpg?dl=0

My bird appears to have very small white armpits - they are present but are not long enough to extend into the 'armpits' of the wing. This gives rise to a rather pointed appearance of what should be the rounded oval sides of the egg-shaped belly patch. But what is important is that, regardless of the white armpits' length, they emerge from the center of the belly patch and not the anterior part closest to the black breast band.

To eliminate the minority of CIF juveniles that lack the white armpits, the shape of the white belly patch is also useful. In the said CIFs, they have a clearly hexagonal belly patch with no pointed corners on the lateral flanks of the belly, like David James's picture that is referred to in his article and can also be found here http://orientalbirdimages.org/search.php?Bird_ID=1175&Bird_Image_ID=8563&p=50.

All factors considered, I am quite confident that my frigatebird is a juvenile GF and not a CIF.

However, I have also emailed David James himself using his email address that I found on the internet. He has yet to reply to me, so I'll reserve judgment until he does.

If you wish to have a PDF copy of David James's article, I can email it to you.

Thanks for all of your help!

 

[Hor Kee]

For completeness sake, here's a shot from below of my frigatebird.