18 May 2013

Collared Pratincoles lacking white trailing edge to wing

Whilst birding at Sabkhat Al Fasl in April I saw a flock of ten Collared Pratincoles with at least three birds without the normal white trailing edge to the secondaries. Initially there was only one bird present and it lacked the white trailing edge, but on closer inspection it had rufous underwing coverts making it a Collared or Oriental Pratincole. The lack of white trailing edge and rufous underwing coverts are features of Oriental Pratincole so I took a few photographs of the bird. I managed to obtain one with its wings stretched showing the lack of white trailing edge to the secondaries. The bird than flew and was joined by the other birds, all of which seemed to be Collared Pratincoles, although two more lacked the white trailing edge. A few birds were typical Collared Pratincoles with long tails and broad white trailing edge to the wing in flight. When resting on the ground there did not appear to be any difference in size, plumage or colouration between any of the birds. As a result I came to the conclusion that all the birds were probably Collared Pratincoles but thought I should get a second opinion as Oriental Pratincole has not, to my knowledge, been recorded in Saudi Arabia. The problem with the interesting bird, first photograph below, was it was on its own when thoughts of Oriental Pratincole entered my head. Unfortunately it then flew some distance and landed, but when we drove to where it had landed it was with a group of other Collared Pratincoles. I found what I thought was the same bird, photographs two and three below, at the edge of the group and took photos of it. It eventually flew off, when I failed to get a flight shot, but did notice the bird lacked an obvious white-trailing edge to the wing and had red underwing coverts. I thought this bird may have been the same bird as that shown in the first photograph due to it having a short looking tail and longer wings but on looking at the photos this was not the case as the bird has one wing dropped down causing an illusion of a short tail and the tail is in fact quite long. As a result I cannot be certain photographs two and three below are the same bird as photograph one below. Likewise the bird in flight may not be the same as the previous bird(s) but certainly lacks an obvious white trailing edge to the wing.

I sent some photos of the interesting birds for comments to a few people with extensive knowledge of the species such as Gerald Driessens, Brian Small,  & Lars Svensson with Gerald and Lars having written an excellent identification paper on Collared and Oriental Pratincoles.
Driessens, G & Svensson, L. 2005. Identification of Collared Pratincole and Oriental Pratincole – a critical review of characters. Dutch Birding 27: 1-35.

Brian mentioned that the apparently evenly dark secondaries and lack of white trailing edge initially confused him but he came to the conclusion the bird was a Collared Pratincole, although suggested it was definitely worth getting a second opinion as the bird was not a typical, easy to identify, Collared Pratincole. He reached his conclusion for the following reasons:
Flight above - note the dark shaft of Oriental Pratincole this bird has white shaft. Flight below - orange breast band seems to grade broadly onto underparts on Oriental Pratincole unlike this bird
Flight - fanned tail shows minimal amount of black on outer tail feather on Oriental (20%) and is usually about half on Collared Pratincole like on the bird in flight

Gerald Driessens mentioned to me that after taking his time to look at the photographs he became convinced that the bird in the first picture (and also the others) showed a Collared Pratincole. He mentioned that there certainly is ‘something strange’ with (some of) the Middle Eastern Collared Pratincoles, with several pictures of odd individuals reaching him since he published the ID-paper. To quote from Gerald “Your bird looks quite compact, somewhat Oriental-like. If it is the same bird as in the next two pictures, the tail streamers are certainly too long (not visible on the first photograph). If it is not the same, than still the pale tips of the secondaries are too washed out and there is too much merging with the dark part of the feather. On Oriental, you see a sharp demarcation with the pale fringe (if there is a fringe in the first place). Also, in my opinion, the spread primaries show a difference between dark outer and paler inner webs on the 4 to 5 inner primaries. As you noticed yourself, the picture of the flying bird shows the typical tail pattern, the outer tail-feather immediately ruling out Oriental, as the dark base never reaches halfway up the shaft in that species”.

Lars Svensson agreed with Gerald’s views saying that on looking a little more at the photographs he “saw that characters for Collared dominated over some vague Oriental-looking traits. Difficult bird(s) anyway”.

Surprisingly quite a few (+/- 25%) of the Collared Pratincoles I have seen in spring in Saudi Arabia appear to lack an obvious white trailing edge to the wing. I wondered if these birds were the African sub-species known as Afrotropical Oriental Pratincole in Gerald Driessens paper:
Driessens, G 2005. Field identification of Afrotropical Collared Pratincole. Dutch Birding 27: 35-40.
The bill pattern and head pattern of these should look more like Oriental Pratincole, and the necklace should have less obvious pale inner throat surround to the black boarder not shown by these birds, so these birds fitted Collared Pratincole better. As a result I concluded they were not Afrotropical Collared Pratincole even though they showed a long black gape line stripe typical of this type.

I asked Gerald and Lars if they had seen birds without the white-trailing edge to the wing, as I had not seen this documented anywhere, and got the following reply. Gerald said “We were able to find some skins with very narrow, and some completely worn off (which is surely not the case in yours) trailing edges. I don’t expect them to be Africans, as they have quite some other characters which are not shared by your bird (like the white edge inside the dark throat band. Would be interesting to know the origin of the Saudi-Arabian birds...”.

Lars said “Personally I have never seen such a white-trailing-edge-lacking Collared Pratincole before, but the whole reason for the paper, which Gerald started and I was invited later to join, was the occurrence of such a bird”.

Here are some photos taken in Saudi Arabia of a reasonably well marked Collared Partincole taken this spring

A poorly marked bird in spring 2012

The conclusion that the birds are Collared Pratincoles was agreed to by all parties but these pictures certainly show that you need very good views of a vagrant bird before coming to the conclusion it is an Oriental Pratincole. This was a great learning experience and I will certainly be looking at all the Pratincoles I see very closely, to see if I can learn anything more. I would like to thank Gerald, Brian and Lars for their thoughts on this interesting bird(s) and for allowing me to publish their comments.