tomjenner
Well-known member
A couple of weeks ago I photographed a vireo on the coast of El Salvador that I thought was a Mangrove Vireo (Vireo pallens). I recently developed the photos and noticed that the bird looks much more like a White-eyed Vireo (Vireo griseus), a species not yet recorded in El Salvador (though a long overdue vagrant). I have very little experience with griseus (White-eyed Vireo) and I was hoping that some of you could give your views. I have outlined some of my thoughts below and included two photos of the bird and a photo of a known Mangrove Vireo, from Bahia de Jiquilisco in El Salvador, for comparison.
The distinctive pale whitish iris of the Jiboa bird is characteristic of griseus (White eyed Vireo). Stiles and Skutch describe the eye colour of pallens (Mangrove Vireo) as pale brown to yellow, whilst Land and Peterson and Chalif describe it as dark on the Pacific slope and whitish to light brown on the Caribbean slope. The Jiquilisco pallens (Mangrove Vireo) has a distinctly dark eye.
Peterson and Chalif describe pallens as having a dull yellow eye stripe instead of eye-ring. Stiles and Skutch describe the loral stripe of pallens (Mangrove Vireo) as continuing narrowly half way around the eye. The bird in these photographs has yellow extending over and behind the eye, but not underneath it. Sibley clearly pictures the yellow of griseus (White-eyed Vireo) extending right around behind and under the eye as does the photo in Farrand. This feature would suggest that the Jiboa bird is more likely to be pallens (Mangrove Vireo), even though it shows slightly more yellow around the eye than the Jiquilisco pallens (Mangrove Vireo).
Land describes the eye stripe of pallens (Mangrove Vireo) as dull yellow and the eye stripe of griseus (White-eyed Vireo) as yellow. Howell and Webb describe them both as yellow, but the plate shows it as a dull pale yellow in pallens compared to a much brighter yellow in griseus(White-eyed Vireo). Stiles and Skutch describe a yellowish-white loral stripe for pallens (Mangrove Vireo) and bright yellow spectacles for griseus (White-eyed Vireo). The Jiboa bird has bright yellow spectacles, compared to the paler, whitish-yellow colour in the Jiquilisco pallens (Mangrove Vireo). This feature suggests that the Jiboa bird is more likely to be griseus (White-eyed Vireo).
Plates in all guides show both species as having dark bills. However, Stiles and Skutch mention that pallens (Mangrove Vireo) has a grayish upper mandible and flesh-coloured lower mandible with a horn-coloured tip, whilst Howell and Webb describe it as grayish. They describe the upper mandible of griseus (White-eyed Vireo) as being black and the lower mandible as grey. The Jiboa bird has a pale, flesh-coloured bill that is slightly greyer on the upper mandible. This is similar to the photo of pallens (Mangrove Vireo) taken at Jiquilisco. This feature suggests that the Jiboa bird is pallens (Mangrove Vireo).
It is not clear from the literature that I have seen whether the lores of griseus (White-eyed Vireo) meet to give a yellow forehead. The lores of the Jiboa bird do not meet.
In summary, this bird appears to show the features of both griseus (White-eyed Vireo) - bright yellow lores and whitish iris - and pallens (Mangrove Vireo) - pale flesh-coloured bill and lack of a complete eye ring. There is some debate about whether the two forms should be considered a separate species, so this could be evidence in favour of that.
Tom
The distinctive pale whitish iris of the Jiboa bird is characteristic of griseus (White eyed Vireo). Stiles and Skutch describe the eye colour of pallens (Mangrove Vireo) as pale brown to yellow, whilst Land and Peterson and Chalif describe it as dark on the Pacific slope and whitish to light brown on the Caribbean slope. The Jiquilisco pallens (Mangrove Vireo) has a distinctly dark eye.
Peterson and Chalif describe pallens as having a dull yellow eye stripe instead of eye-ring. Stiles and Skutch describe the loral stripe of pallens (Mangrove Vireo) as continuing narrowly half way around the eye. The bird in these photographs has yellow extending over and behind the eye, but not underneath it. Sibley clearly pictures the yellow of griseus (White-eyed Vireo) extending right around behind and under the eye as does the photo in Farrand. This feature would suggest that the Jiboa bird is more likely to be pallens (Mangrove Vireo), even though it shows slightly more yellow around the eye than the Jiquilisco pallens (Mangrove Vireo).
Land describes the eye stripe of pallens (Mangrove Vireo) as dull yellow and the eye stripe of griseus (White-eyed Vireo) as yellow. Howell and Webb describe them both as yellow, but the plate shows it as a dull pale yellow in pallens compared to a much brighter yellow in griseus(White-eyed Vireo). Stiles and Skutch describe a yellowish-white loral stripe for pallens (Mangrove Vireo) and bright yellow spectacles for griseus (White-eyed Vireo). The Jiboa bird has bright yellow spectacles, compared to the paler, whitish-yellow colour in the Jiquilisco pallens (Mangrove Vireo). This feature suggests that the Jiboa bird is more likely to be griseus (White-eyed Vireo).
Plates in all guides show both species as having dark bills. However, Stiles and Skutch mention that pallens (Mangrove Vireo) has a grayish upper mandible and flesh-coloured lower mandible with a horn-coloured tip, whilst Howell and Webb describe it as grayish. They describe the upper mandible of griseus (White-eyed Vireo) as being black and the lower mandible as grey. The Jiboa bird has a pale, flesh-coloured bill that is slightly greyer on the upper mandible. This is similar to the photo of pallens (Mangrove Vireo) taken at Jiquilisco. This feature suggests that the Jiboa bird is pallens (Mangrove Vireo).
It is not clear from the literature that I have seen whether the lores of griseus (White-eyed Vireo) meet to give a yellow forehead. The lores of the Jiboa bird do not meet.
In summary, this bird appears to show the features of both griseus (White-eyed Vireo) - bright yellow lores and whitish iris - and pallens (Mangrove Vireo) - pale flesh-coloured bill and lack of a complete eye ring. There is some debate about whether the two forms should be considered a separate species, so this could be evidence in favour of that.
Tom
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