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M. Bryant J. Reynolds (MS, 2006)
"Conservation taxonomy of the Cuban Parrot: plumage, morphology, and flight call variation." |
Contact - Bryant has graduated and is now in Minnesota.
Email: mbryantjreynolds@gmail.com
Self portrait. Bryant pauses in the afternoon sun while searching for Cuban Parrots on Inagua, The Bahamas. He visited the island in January, 2006, to procure recordings of the parrots. Photograph: M. Bryant J. Reynolds.
After Bryant volunteered for two summers to assist our studies of endangered Bahama rock iguanas, returning to The Bahamas seemed like a natural thing to do. After learning about the potential for several endemic Bahamian bird species to be elevated to full species status, he chose to study the Cuban Parrot (Amazona leucocephala). This gorgeous bird, though formerly more widespread, presently lives on six islands in the West Indies, including two islands in The Bahamas (Abaco and Inagua). Bryant examined museum specimens to compare morphology and plumage among the different populations, and he also quantified the spectrographic features of contact calls from each population. To acquire recordings, he traveled to Abaco and Inagua in January, 2006. He obtained additional calls from Cuba, Isla de Juventud, and Little Cayman from a collaborator, James Wiley. Calls from Grand Cayman were supplied by his professor, William Hayes.
Cuban Parrot (Amazona leucocephala) displaying its colorful tail. This lovely bird was interacting with another of its kind behind the Visitors Center at Queen Elizabeth II Botanical Gardens, Grand Cayman Island. Photograph: Pat Barry.
Thesis abstract
Conservation taxonomy, the study of organismal classification to clarify conservation priorities, seeks to define species and subspecies limits. Allopatric populations, such as those present on islands, pose special challenges to identifying taxonomic boundaries that can be practically addressed using diagnostic criteria. Because some of the island populations of Cuban Parrot (Amazona leucocephala) are highly endangered, the five recognized subspecies need careful re-evaluation. I measured 18 morphological and plumage characters from 188 museum specimens representing the six extant and one extirpated island populations. I also examined 11 spectrographic characters from the flight calls of 23 parrots representing all six extant populations. I relied largely on discriminate function analyses (DFA) to assess diagnosability and examine patterns of similarity among the populations.
Most morphological characters indicated sexual dimorphism, with males 1-4% larger than females. The plumage characters, in contrast, demonstrated complete absence of sexual dichromatism. Stepwise discriminant analyses including all specimens and 14 characters revealed substantial differentiation among island groups, with 81.4% of individuals classified correctly to island. Pairwise comparisons among islands showed reciprocal discrimination >80%, with the exception of Cuba/Cayman Brac (67%). None of the populations possessed a single diagnostic character. Although currently lumped into a single subspecies, each of the three Bahamas populations (including an extirpated population) was equally distinct as the four other currently-recognized subspecies.
Parrots from each island possessed distinct flight calls, leading to full diagnosis for all but the Cuba/Isla de la Juventud populations. Diagnostic characters were usually qualitative (Abaco: paired syllables; Inagua: frequency jump; Cuba/Isla de la Juventud: subharmonics), but Cayman Brac calls had diagnostic syllables of long duration. Discriminant analyses indicated that the quantitative characters were most similar for Cuba, Isla de la Juventud, and Grand Cayman, with those from Abaco and Inagua (The Bahamas) and Cayman Brac being most distinct.
Collectively, the evidence supports the view that all island populations, including the extirpated population from Acklins Island (The Bahamas), warrant subspecies status. The Abaco population, which is unique among New World parrots in nesting on the ground, should be considered a candidate for elevation to full species. Current management practices should be revised to reflect the degree of diversity exhibited in this group.
Reynolds, M. B. J. 2006. Conservation taxonomy of the Cuban Parrot: plumage, morphology, and flight call variation. Unpublished MS thesis, Loma Linda University, Loma Linda, California.
Last Revised: Tue, Jan 30, 2007
