Analyses of museum specimens uncover hybrid jays in Brazil

Ornithologists identified hybrids between Plush-crested Jay and the White-naped Jay.

In 2015, I estimated that about 16 percent of bird species hybridize. In that paper, I also wrote that “these numbers are most probably underestimates, given our generally poor knowledge of the breeding biology of several bird groups, such as cryptic tropical species.” There are probably numerous bird hybrids waiting to be discovered in the tropical regions. A recent study in the journal Zoologia reports such as case: two putative hybrids between the Plush-crested Jay (Cyanocorax chrysops) and the White-naped Jay (C. cynanopogon) in Brazil.

A Plush-crested Jay in Argentina © Tim Sackton | Flickr

 

Intermediate Specimens

In 1954, Pinto described a new taxon – called Cyanocorax chrysops interpositus – based on a single specimen. He considered is an intermediate form between Plush-crested Jay and the White-naped Jay (hence the name interpositus). A few decades later, John Hardy questioned the existence of this taxon and argued that it probably concerned aberrant specimens of the White-naped Jay (e.g., molting birds or subadults). Or could they have been hybrids?

Recently, Cristiane Apolinario and Luis Fabio Silveira found two museum specimens with intermediate plumage patterns. They analyzed the plumage characters and the geographical locations of these specimens. The birds showed intermediate traits when compared to the two Cyanocorax species. Specifically, the dark grayish brown color of the wings and light blue color of the neck. Moreover, both specimens were found in a contact zone between Plush-crested Jay and the White-naped Jay.

One of hybrid specimens (number 2) between Plush-crested Jay (1) and the White-naped Jay (3). Notice the brownish color of the wings and the white-blue pattern on the neck of the hybrid. From: Apolinario & Silveira (2019) Zoologia

 

Hybrid Zone?

The morphology and the geographical location of these specimens suggest that they are hybrids. But genetic data are needed to confirm this conclusion. Nevertheless, this interesting finding raises the possibility of a hybrid zone between these species. But why hasn’t this putative hybrid zone been found earlier? The authors offer two possible explanations: (1) the hybrids are too similar to the parental species to detect or (2) hybridization between these species is very rare. I think it is time for a trip to Brazil…

White-naped Jay © Hector Bottai | Wikimedia Commons

 

References

Apolinario, C., & Silveira, L. F. (2019). Hybridism between Cyanocorax chrysops and Cyanocorax cyanopogon (Aves: Corvidae) in Brazil. Zoologia, 36, 1.

Hardy JW (1969) A taxonomic revision of the New World jays. The Condor 71(4): 360–375.

Ottenburghs, J., Ydenberg, R. C., Van Hooft, P., Van Wieren, S. E., & Prins, H. H. (2015). The Avian Hybrids Project: gathering the scientific literature on avian hybridization. Ibis, 157(4), 892-894.

Pinto, O. (1954) Resultados ornitológicos de duas viagens científicas ao estado de Alagoas. Papéis do Departamento de Zoologia 12(1): 1–98.

 

This paper has been added to the Corvidae page.