Recent paper introduces some intergeneric parrot hybrids.
On the Spanish island Tenerife (Canary Islands), Dailos Hernández-Brito and his colleagues observed a peculiar breeding pair. A male Orange-winged Amazon (Amazona amazonica) and a female Scaly-headed Parrot (Pionus maximiliani) produced seven hybrid offspring. The hybrids came in two morphological types: one type was more similar to the male parent, whereas the other resembled the female parent more. The genera that these species belong to – Amazona and Pionus – diverged about 10 million years ago. A long time, but still within the known limits of avian hybridization (maximum divergence time for a bird hybrid is ca. 47 million years of divergence, see this blog post).
In their discussion, the authors noted that “To our knowledge, the only instance recorded in the wild occurred between the last free-living male Spix Macaw Cyanopsitta spixii and a female Blue-winged Macaw Primolius maracana, which after three breeding seasons only produced an unviable embryo.” This statement caught the attention of Andrew Hingston, who presented additional cases of intergeneric hybrids between parrot species in a short Ibis-paper. He indicated that the authors probably missed these cases because they were published in regional Australian journals, such as Australian Bird Watcher and Tasmanian Bird Report.
Two Australian Cases
The first case concerns hybridization between Rainbow Lorikeet (Trichoglossus moluccanus) and Musk Lorikeet (Glossopsitta concinna) on Yorke Peninsula in South Australia. Several birds with intermediate phenotypes were photographed. However, it might still concern individuals with aberrant plumage colors. Observations of pairings between Rainbow and Musk Lorikeet provided some evidence for hybridization. Another intergeneric parrot hybrid was reported on eBird: a putative cross between Galah (Eolophus roseicapillus) and Little Corella (Cacatua sanguinea).
Both cases are definitely interesting and possible, but I would nonetheless call for genetic analyses to confirm these hybrids. As James Alfieri and his colleagues wrote in a recent Ecology and Evolution paper: “genetic approaches, such as whole-genome sequencing, remain the gold standard for validating hybridization events.”
All the intergeneric hybridization events have one thing in common: one of the parental species formed a small population with limited access to conspecific partners. These birds might have settled for a partner of a different species (even belonging to another genus), because they could not find a mate of their own species. This situation is known as Hubb’s Principle. Although I prefer the more explicit term: the “Desperation Hypothesis”. Desperate times call for desperate measures…
Hernández‐Brito, D., Tella, J. L., Carrete, M., & Blanco, G. (2021). Successful hybridization between non‐congeneric parrots in a small introduced population. Ibis, 163(3), 1093-1098.
Hingston, A. B. (2022). Hybridization between wild non‐congeneric parrots may be more common than previously thought. Ibis, 164(2): 603-605.
Featured image: Rainbow Lorikeet (Trichoglossus moluccanus) © Andrew Mercer | Wikimedia Commons