Dinâmica temporal de beija-flores (Aves: Trochilidae) em uma área de Caatinga no semiárido de Pernambuco, Brasil

Abstract

Flowering phenology of plants are the main factor controlling hummingbird community organization, and it evolves in a given area as a unit in such a manner that the presence of a plant species can affect the phenology of other plant species. Nowadays there is little information available on the dynamics of biological communities in the Caatinga. The objective of the present study was to describe the temporal distribution in species richness and abundance of hummingbirds, and also in their reproductive activities, molt cycle, richness of flowering ornithophilous and non ornithophilous plant species, verifying the influence of the availability of flowering resources and of climatic factors in the dynamics and in the annual cycle of the hummingbird assemblage during a two year period study in an area of Caatinga. We also present morphometric data. The study was conducted in an area of shrubarboreal caatinga vegetation, located at Serra do Pará, municipality of Santa Cruz do Capibaribe, Pernambuco, Brazil. Hummingbird abundance varied seasonally, with peaks being observed during the rainy season. Temperature had a negative effect on both the species richness and abundance of hummingbirds. The dynamics of the hummingbird assemblage at Serra do Pará was influenced by resource availability, with abundance being higher during periods of lower temperatures and when higher numbers of non ornithophilous plants were flowering. Reproductive activity was evident during the rainy season. Molt, especially contour feathers and flight feathers occurring simultaneously was concentrated after the rainy season in the studied area. The assembly studied presented a bimodal cycle in reproductive activity and molt, which in turn were associated with flower availability. These two events were in asynchrony, with molt cycles beginning after the reproductive period. The hummingbird assembly was morphologically characterized by the three sub-groups known for the Trochilinae, presenting small short-billed species, medium-sized with straight bills species, and the medium to large with long bills species. The information presented in this study contribute with ecological and morphological characteristics of some hummingbird species distributed within the Caatinga, and also new information on hummingbird dynamics and their annual cycles in an area of Caatinga.