Great Lizard-Cuckoo

Frontiers of Taxonomy: Are We Splitting the Great Lizard-Cuckoo?

The Handbook of the Birds of the World Alive regards the Cuban and Bahaman forms of Great Lizard-Cuckoo as two species, separating bahamensis, the “Bahama Lizard-Cuckoo,” from the other three recognized subspecies (merlini, santamariae, and decolor), the “Cuban Lizard-Cuckoo,” based on three cited differences in plumage.  The proposed split may eventually gain widespread acceptance, but that will likely require further research and analysis, particularly in light of the considerable plumage variation within the three “Cuban Lizard-Cuckoo” subspecies, and the absence of clear vocal distinctions between the “Bahama” and “Cuban” forms.

In general, bahamensis differs visibly from most “Cubans” in being much grayer overall, lacking the “Cuban’s” typically warm-brown upperparts and rusty tones.  However, the two subspecies that occupy adjacent Cuban islands—santamariae (Jardines del Rey Archipelago) and decolor (Isle of Youth)—also average much grayer than the mainland Cuban subspecies, merlini.  Facially, the most evident difference seems to be between the widespread merlini and the three more localized subspecies, which suggests that “Bahama” has not diverged fundamentally.

The Handbook states that in comparison to “Cuban,” bahamensis differs in having: (1) less extensive rufous in the primaries; (2) a black tip on the uppertail (apparently referring to the upperside of the two central retrices); and (3) purer gray on the breast and paler rufous on the lower underparts.  The authors prioritize the rufous wing-patch as more significant than the other two distinctions.

Based on a review of published photographs, it is not clear that the underparts coloration differs at all between the two forms, as bahamensis seems to fall within the “Cuban” subspecies’ wide spectrum of variation.  The two remaining plumage differences may be more consistent distinguishing features, but their taxonomic significance is not self-evident.  Details of tail and wing coloration appear to vary widely across the Great Lizard-Cuckoo as a whole, and this intrinsic variation makes it difficult to draw definitive lines.

Several recordings of bahamensis and merlini vocalizations are available in the online Macauley Library.  Both subspecies give various types of vocalizations, varying in pitch, phrasing, rate, and duration.  Upon review of these recordings and those posted on xeno-canto.org, it seems apparent that both subspecies have similar repertoires, consisting of: extended staccato rattling, briefer rattles, isolated clucks, mutters, and a distinctly phrased two-syllable tk!-AAAWW.