The hybrid resembles a Rufous Motmot but has some peculiar plumage patterns.
How common is hybridization in birds? The answer to this question depends on whether you refer to hybridization on the individual level or the species level. If you consider the individual level, hybridization is mostly rare, only a small proportion of wild bird populations will consist of hybrids. Using the online database eBird, a recent study reported just 0.064 percent avian hybrids in North America (this percentage is probably a lower bound, as explained in this paper). On a species level, hybridization is a relatively common phenomenon among birds. The latest estimate indicated that 16.4 percent of bird species have hybridized in the wild. This percentage is probably an underestimate, given our generally poor knowledge of the breeding biology of several bird groups, such as cryptic tropical species.
Due to the rarity of hybridization on the individual level, it is often challenging to find new hybrid combinations. Occasionally, however, observant ornithologists do manage to identify previously unknown hybrids. A recent paper in the journal Ornithology Research, for example, reported a hybrid between two Motmot species.
Rufous Motmot or not?
During a birding trip in Brazil, a group of birdwatchers noticed a Rufous Motmot (Baryphthengus martii) with some abnormal features. A standard Rufous Motmot can be identified by the black mask that runs along its orange head. This specimen, however, had some conspicuous blue lines above and below the mask. In addition, the birdwatchers noticed a patch of distinct blue feathers on the black spot that adorned its neck. Finally, the tail of this bird sported some terminal racquet-shaped feathers, a feature that is only present in population from the Andes (subspecies semirufus). All these peculiar traits pointed to another Motmot species that occurs in the area: Amazonian Motmot (Momotus momota).
The conclusion that this abnormal specimen might be a hybrid between these two species was supported by an additional observation. When the birdwatchers played the song of the Rufous Motmot to attract the bird for a picture, a mixed group of four motmots (with two Rufous Motmots and two Amazonian Motmots) approached. The intermingling of these species – which also display similarities in courtship – suggests that the occasional hybrid might be produced.
Pablo Vieira Cerqueira and his colleagues searched several online databases for more pictures of this hybrid combination, but only found one possible hybrid in the photographic database Wikiaves. This indicates that hybridization is probably rare on an individual level (as explained above) or that hybrids between these species are difficult to detect.
In general, Motmot hybrids have rarely been documented. Rafael Marcondes and his colleagues described a hybrid between Amazonian Motmot and the Rufous-capped Motmot (Baryphthengus ruficapillus) from central Brazil. And the Handbook of Avian Hybrids of the World by Eugene McCarthy mentions a cross between Amazonian and Andean Motmot (Momotus aequatorialis), but without reliable evidence. Finally, some sources reported a mixed pair of Keel-billed Motmot (Electron carinatum) and Broad-billed Motmot (Electron platyrhynchum), but no hybrid offspring were observed. These cases suggest that hybridization between Motmot species might be more common than we assumed. Who know what curious crosses are hidden in the Brazilian rainforest?
Cerqueira, P. V., Gonçalves, G. R., & Aleixo, A. (2020). Two intergeneric hybrids between motmots from the Amazon forest: Rufous Motmot (Baryphthengus martii)× Amazonian Motmot (Momotus momota). Ornithology Research, 28(1), 57-60.
This paper has been added to the Coraciiformes page.