Abstract
This study investigates the relationship between morphological similarity and ecological overlap among 11 spp. of passerine birds [Tyrannus dominicensis dominicensis (Gmelin), Myiarchus tyrannulus berlepschii (Cory), Elaenia martinica martinica (L.), Margarops fuscatus fuscatus (Vieillot), Allenia fusca (Muller), Cinclocerthia ruficauda pavida (Ridgway), Vireo altiloquus barbadensis (Ridgway), Coereba flaveola dominicana (Taylor), Dendroica petechia bartholemica (Sundevall), Loxigilla noctis coryi (Ridgway), Tiaris bicolor omissa (Jardine)] inhabiting 2nd-growth forests on the island of St. Kitts in the Lesser Antilles. Morphological similarity was based on body size, wing/tarsus ratio and bill proportions. Ecological overlaps between species were based on foraging method, feeding location in the habitat and distribution among habitats. Overlap in foraging method was strongly correlated with similarity in the wing/tarsus ratio; overlap in feeding location was additionally correlated with similarity in bill structure; habitat overlap was not, however, related to morphological similarity. Morphology can apparently be used as an index to ecological relationships among species coexisting in the same habitat.