White Ibis x Scarlet Ibis hybrid, Aruba Salina (Aruba, off Venezuela), 12th April 2017 - copyright Steve Mlodinow
(photo ID: 3202)
Steve tells us that this hybrid isn't at all rare in some colonies in northern Venezuela and Columbia leading some to speculate that Scarlet and White Ibises are colour morphs of the same species. In an article in Colonial Waterbirds 10.1 111-114, Cristina Ramo and Benjamin Busto document 40 mixed pairs and 14 mixed copulations in the Venezuelan Llanos and proposed that they should be treated as different subspecies of one species. But whether they are colour morphs, different subspecies or different species, most if not all of the main taxonomic authorities are still treating them as separate species at the moment.
It is reported that captive Scarlet Ibises receiving inadequate levels of β-keratin in their diet turn pink, and such birds may be difficult to distinguish from hybrids (see The Chat 53: 90-91 for example). If anyone has any information on how they may be differentiated, please get in touch.
In Aruba neither species is common. Steve tells us that Scarlet Ibis has been nearly annual during the last 5 years, with 2-3 birds involved. This is the first hybrid. A White Ibis with an abnormally dark bill turned up the day after the hybrid - here they are together:
White Ibis x Scarlet Ibis hybrid (right, with White Ibis; same bird as in photo ID 3202 above), Aruba Salina (Aruba, off Venezuela), 14th April 2017 - copyright Steve Mlodinow
(photo ID: 3203)
White Ibis Eudocimus albus
Scarlet Ibis Eudocimus ruber
Really interesting that they hybridize so readily in the wild—makes you wonder if the taxonomic split will eventually get reconsidered. I've been using lately to keep track of bird sightings and observations, and it's been handy for comparing notes with other birders.
ReplyDeleteThe hybrid is such an interesting find, especially since mixed White and Scarlet Ibis pairings seem to raise bigger questions about where the boundaries between species actually lie. I also find the Aruba record fascinating because neither species is common there, making a first hybrid observation particularly noteworthy. For something completely different: roulettino
ReplyDeleteWhat a fascinating find! The mix of the White and Scarlet Ibis is surprisingly subtle, and the fact that hybrids occur regularly in some Venezuelan colonies makes the whole species-versus-subspecies question even more intriguing. After reading about such unusual birds, I’d happily take a little break at rubyreels
ReplyDeleteWhat I appreciate most is how this kind of post captures the ongoing tension in ornithology between what we observe in the field and what official authorities decide. Science is a living process, and field observations like Steve Mlodinow's are exactly what eventually push classifications to evolve. It's the same satisfaction you get from any area where careful observation and clear information pay off — whether you're tracking bird sightings or just exploring something new, having reliable sources makes all the difference. I've found that same clarity at https://spinwineras.net Wonderful post for anyone curious about hybridisation in the wild. Keep those field notes coming!
ReplyDeletethis is a really interesting example of how difficult bird identification and classification can be. the discussion about whether these ibises are color morphs, subspecies or separate species shows how much there is still to learn from observations in the field. i also found the detail about diet affecting the color of captive Scarlet Ibises particularly fascinating, since it can make hybrids even harder to identify. i also came across insta spin while browsing.
ReplyDeleteThe White Ibis (Eudocimus albus) and Scarlet Ibis (Eudocimus ruber) are two remarkably similar wading birds. Their most obvious difference is their plumage: one is predominantly white, while the other has the spectacular scarlet-red coloration that gives it its name. Both have long, curved bills, pinkish legs and the characteristic body shape of an ibis.
ReplyDeleteWhat makes the pair especially interesting is that they can hybridize. Their ranges overlap in parts of northern South America, particularly in Colombia and Venezuela, where mixed pairs and hybrid offspring have been documented. Hybrid birds can show intermediate or unusual coloration, including pale orange, pinkish or predominantly white plumage with reddish feathers.
The relationship between the two birds has also created an interesting taxonomic debate. Some researchers have argued that their ability to interbreed and their remarkable similarity suggest that they could be treated as forms or subspecies of a single species. Genetic research, however, has found evidence that the White and Scarlet Ibises represent distinct evolutionary lineages, supporting their treatment as separate species.
Today, hybrid White × Scarlet Ibises continue to be recorded in the wild. Recent observations documented by the Macaulay Library and eBird include hybrid birds in Colombia, demonstrating that this is not simply a historical curiosity.
The White Ibis and Scarlet Ibis therefore offer a fascinating example of how nature does not always fit neatly into categories. Their similarities, differences and ability to produce hybrids make them particularly interesting subjects for birdwatchers and anyone fascinated by evolution and variation. More stories about birds, wildlife and nature can also be explored on https://chicken-subways.net.