Red-eyed Vireo / Chivi Vireo (1 Viewer)

Andy Adcock · Apr 5, 2020

I've been looking at images of birds ID'd as Chivi Vireo and struggling to pick out any real differences, the only thing I can seem to see, is bright, yellow, undertail coverts which can be a feature of Chivi, too yellow for Red-eyed?

Can anyone chip in on this bird from SE Venezuela near the Brazilian and Guyanan border, Jan 16 when the presence of migrants, complicates an already muddy picture.

Can they even be done safely apart from vocally?

THE_FERN · Apr 5, 2020

andyadcock said:
I've been looking at images of birds ID'd as Chivi Vireo and struggling to pick out any real differences, the only thing I can seem to see, is bright, yellow, undertail coverts which can be a feature of Chivi, too yellow for Red-eyed?

Can anyone chip in on this bird from SE Venezuela near the Brazilian and Guyanan border, Jan 16 when the presence of migrants, complicates an already muddy picture.

Can they even be done safely apart from vocally?

In Peru, chivi has brown eyes, and I think red-eyes doesn't. In theory voice is the most distinctive feature. By "brown eyes", in the field this often equates to "dark, not obviously red" ime. I think I posted on this before some time ago where I quoted an old paper that talked about other distinguishing characters.

Andy Adcock · Apr 5, 2020

THE_FERN said:
In Peru, chivi has brown eyes, and I think red-eyes doesn't. In theory voice is the most distinctive feature. By "brown eyes", in the field this often equates to "dark, not obviously red" ime. I think I posted on this before some time ago where I quoted an old paper that talked about other distinguishing characters.

Thanks,
so how would you evaluate this bird on eye colour, looking at images for Red-eyed, there are loads with seemingly dark eyes and few that actually show, really red eyes?

Is the undertail too yellow for Red-eyed? I've looked at images from N America and can't see any examples of Red-eyed with bright undertail like this and it is mentioned as being an occasional feaure of Chivi.

THE_FERN · Apr 5, 2020

andyadcock said:
Thanks,
so how would you evaluate this bird on eye colour, looking at images for Red-eyed, there are loads with seemingly dark eyes and few that actually show, really red eyes?

Is the undertail too yellow for Red-eyed? I've looked at images from N America and can't see any examples of Red-eyed with bright undertail like this and it is mentioned as being an occasional feaure of Chivi.

Obviously it's easier in the field, but I wouldn't make this red-eyed. I remember some chivis having clearly brown eyes. I think yours has "browner" eyes and so is probably chivi. Perhaps if I've time/access to a computer I'll find the old thread. But I've never been to that area...

Andy Adcock · Apr 5, 2020

THE_FERN said:
Obviously it's easier in the field, but I wouldn't make this red-eyed. I remember some chivis having clearly brown eyes. I think yours has "browner" eyes and so is probably chivi. Perhaps if I've time/access to a computer I'll find the old thread. But I've never been to that area...

Many thanks.

THE_FERN · Apr 5, 2020

andyadcock said:
Many thanks.

This is the other post, I thinK: includes a link to Todd's paper—

https://www.birdforum.net/showthread.php?t=386174&highlight=chivi

Andy Adcock · Apr 5, 2020

Many thanks but that link is now deceased.

THE_FERN · Apr 5, 2020

andyadcock said:
Many thanks but that link is now deceased.

? Just clicked it and it came up for me...

njlarsen · Apr 5, 2020

Link works for me?

It essentially states the same about brown eyes in an adult is a sign of Chivi. Unfortunately, in juvenile Red-eyes, the iris is brown or grey-brown. Pyle did not state how quickly it changed to red as far as I could see.

Niels

Edit: BoW has

In hatchlings and during first fall and early winter, iris brown to reddish brown. By end of first winter (March), iris becomes red, shade varying individually in adults from dull brick red to bright crimson.

Cimprich, D. A., F. R. Moore, and M. P. Guilfoyle (2020). Red-eyed Vireo (Vireo olivaceus), version 1.0. In Birds of the World (P. G. Rodewald, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.reevir1.01

Andy Adcock · Apr 5, 2020

THE_FERN said:
? Just clicked it and it came up for me...

Thanks both,
It's the link in the link, to the Todd article that won't open, I've ytried different browsers too?

Would first year birds still show some signs of juvenile plumage in January?

THE_FERN · Apr 5, 2020

andyadcock said:
Thanks both,
It's the link in the link, to the Todd article that won't open, I've ytried different browsers too?

Would first year birds still show some signs of juvenile plumage in January?

>>It's the link...
Urgh! Just tried and firefox opened it easily. It's now attached...

[Might be your settings? If not set to open PDFs, the browser might download by default.]

<edit>; Birds of northern S America describes juvenile red-eyed thus: "...has dark brown eyes, faint supercilium and pale brown crown-sides, mantle, scapulars, and secondary wing-coverts"

Not sure I see anything which matches any [hint] of these in your pic.

Andy Adcock · Apr 5, 2020

THE_FERN said:
>>It's the link...
Urgh! Just tried and firefox opened it easily. It's now attached...

[Might be your settings? If not set to open PDFs, the browser might download by default.]

<edit>; Birds of northern S America describes juvenile red-eyed thus: "...has dark brown eyes, faint supercilium and pale brown crown-sides, mantle, scapulars, and secondary wing-coverts"

Not sure I see anything which matches any [hint] of these in your pic.

Many thanks.

Well, that's as clear as mud! Could my bird be a vividior, seems to be very bright, especially the undertail and the range would fit perfectly per HBW?

'V. o. vividior Hellmayr & Seilern, 1913 – N & C Colombia (S to Meta), Venezuela, the Guianas, extreme N Brazil (N Amazonas, Roraima), and Trinidad.'

Hang on a minute, I'm talking myself out of a tick!

njlarsen · Apr 5, 2020

vividior is shown with a drawing in the TT book by Kenefick, as is chivi and northern (current red-eye) forms. Notice that both Clements and IOC has the first two of these in the Chivi species.

vividior is shown as a form with yellow vent area but whitich undersides otherwise. The chivi is described as dull and dingy. The ReVi form is shown as having yellow flanks with less yellow on undertail. How much variation there is in each of these I do not know, but the text describes the whitish underside in both local and vividior birds, different from chivi and ReVi.

Niels

Nutcracker · Apr 5, 2020

andyadcock said:
Hang on a minute, I'm talking myself out of a tick!

Looks like I'll have to chivvy you into getting it sorted o

Andy Adcock · Apr 5, 2020

njlarsen said:
vividior is shown with a drawing in the TT book by Kenefick, as is chivi and northern (current red-eye) forms. Notice that both Clements and IOC has the first two of these in the Chivi species.

vividior is shown as a form with yellow vent area but whitich undersides otherwise. The chivi is described as dull and dingy. The ReVi form is shown as having yellow flanks with less yellow on undertail. How much variation there is in each of these I do not know, but the text describes the whitish underside in both local and vividior birds, different from chivi and ReVi.

Niels

Yes I saw that but odd as HBW have it under Red-eyed? They even note an endemic race on Tobago which must raise eyebrows?

https://www.hbw.com/species/red-eyed-vireo-vireo-olivaceus

I think my bird is probably a vividior?

njlarsen · Apr 5, 2020

I think there was a rearrangement of that with DNA data that came out in 2018. Given that HBW was based on a system of assigning points based on phenotype and not really had a good way to include DNA data, I am not too surprised they did not include the limitation of ReVi to the northern, migratory form.

https://www.birdforum.net/showthread.php?t=283663 from post 41 and forward is worth checking.

Niels

Birdbrain22 · Apr 5, 2020

njlarsen said:
Link works for me?

It essentially states the same about brown eyes in an adult is a sign of Chivi. Unfortunately, in juvenile Red-eyes, the iris is brown or grey-brown. Pyle did not state how quickly it changed to red as far as I could see.

Niels

Edit: BoW has

Cimprich, D. A., F. R. Moore, and M. P. Guilfoyle (2020). Red-eyed Vireo (Vireo olivaceus), version 1.0. In Birds of the World (P. G. Rodewald, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.reevir1.01

Regarding the eye color... we have definitely had brown eyed birds in hand in the fall of their HY. However, according to my Pyle... "Note: Some spring birds show a brownish cast to the iris;these may be SYs or possibly ASYs that never acquire the full red color; more study is needed."

FWIW and IMO- looks way to yellow for a REVI... especially the wing and tail. No experience with Chivi other than what I saw online.

Andy Adcock · Apr 6, 2020

Birdbrain22 said:
Regarding the eye color... we have definitely had brown eyed birds in hand in the fall of their HY. However, according to my Pyle... "Note: Some spring birds show a brownish cast to the iris;these may be SYs or possibly ASYs that never acquire the full red color; more study is needed."

FWIW and IMO- looks way to yellow for a REVI... especially the wing and tail. No experience with Chivi other than what I saw online.

Many thanks Birdbrain, I'm boarding the train to 'Ticksville'.

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