Help with Ibis Identification - Cancun, Mexico (1 Viewer)

[Butty]

Both the OPs have bright red eyes

I disagree with this. As I've said above, I'd go for reddish-brown or red-brown - and...

eye looks brown in the last shot.

Anyway, as we know, iris colour in anything can be pretty individually/seasonally/etc/etc variable - so no big deal (except that I certainly disagree that this bird's is 'bright red').

Good moult gen

Regardless of age, I think the OPs are almost certainly White-faced - the key criteria here being the diagnostic red irises.

Me too. As we've both said before. And I agree about the key criterion.

 

[Deb Burhinus]

I think this is one bird (at least that is what I understand from the OPs observations.

Therefore, we have to go with the eye colour that is receiving the most light, which looks quite red to me bearing in mind we are looking at a non-breeding plumage.

Just comparing a few online, it seems the intensity of red is variable in adults - recognised factors for intraspecific changes in birds include not only maturation but also changes during the non-breeding period v mating season. Sexual dimorphism could also effect eye colour intensity but without further resource material, all that’s just conjecture of course but the eye certainly looks duller in imm/adult non-breeding plumage

White-faced Ibis Photos and Videos for, All About Birds, Cornell Lab of Ornithology

<p>The handsome White-faced Ibis shimmers with purple, green, and bronze plumage. Breeding adults add to this a ruby-red eye surrounded by a sharp white mask, and pink legs. Flocks of this long-legged bird forage in marshes across large parts of the American West, where wetlands are very scarce...

www.allaboutbirds.org

It is worth reiterating some of the other plumage features of 1w birds that seem to be lacking in this OP bird (as well as my notes on moult on the previous page)
Some good background ID notes and images of a typical 1st Winter November, White-faced Ibis here
http://www.jeaniron.ca/2019/wfibis.htm.

• note the rust brown irises
• greenish plumage (lacking the rusty scaps
• pale cheek patch
• worn/faded primaries

Also compare a 1w Glossy Ibis (29th November further down the page on the above link and note how dark that individual is still too)

 

[Butty]

go with the eye colour that is receiving the most light

I definitely agree. But this one still doesn't look, to me, 'bright red' (I had already viewed the photo that big). Your new alternative 'quite red' is vaguer than I should like, but more nearly-acceptable - in my opinion.

intensity of red is variable in adults - recognised factors for intraspecific changes in birds include not only maturation but also changes during the non-breeding period v mating season. Sexual dimorphism could also effect eye colour intensity

Exactly so. As I (more-or-less) indicated above.

 

[Deb Burhinus]

intensity of red is variable in adults - recognised factors for intraspecific changes in birds include not only maturation but also changes during the non-breeding period v mating season. Sexual dimorphism could also effect eye colour intensity

Exactly so. As I (more-or-less) indicated above.

My understanding is that white-faced ibis has a red(dish) iris at all ages

Apologies, I misunderstood your earlier post 👍

 

[Glaverty]

Thanks to everyone who commented. I have a better appreciation now for how difficult some of these identifications can be. I just wish that the eBird reviewer who classified my photos as 'unconfirmed' had communicated their rationale to me - so that I could understand their position and so that I could learn.