Owl Studies at Ann Arbor, Michigan

Abstract

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org. Ecological Society of America is collaborating with JSTOR to digitize, preserve and extend access to Ecology. Autumn 1964 ANOLINE LIZARDS OF PUERTO RICO 745 Snow, D. W. 1954. The habitats of Eurasian tits (Parus spp.). Ibis 96: 565-585. Stewart, R. E. 1949. Ecology of a nesting red-shouldered hawk population. Wilson Bull. 61: 26-35. , and J. W. Aldrich. 1951. Removal and re-population of breeding birds in a spruce-fir forest community. Auk 68: 471-482. Stresemann, E. 1950. Interspecific competition in chats. Ibis-92: 148. Sutton, G. M. 1930. The nesting wrens of Brooke County, West Virginia. Wilson Bull. 42: 10-17. Trousdale, B. 1954. Copulation of Anna humming-birds. Condor 56: 110. Weeden, J. S., and J. B. Falls. 1959. Differential responses of male ovenbirds to recorded songs of neighboring and more distant individuals. Auk 76: 343-351. Wells, P. V. 1958. Indigo buntings in lazuli bunting habitat in southwestern Utah. Auk 75: 223-224. Willson, M. F., and G. H. Orians. 1963. Comparative ecology of red-winged and yellow-headed blackbirds during the breeding season. Proc. XVI Int. Abstract. The eight species of lizards of the genus Anolis in Puerto Rico can be divided into four morphological groups on the basis of general morphological similarities. One, Anolis cviieri, is very different from the rest and has not been discussed here. The other seven species fall into three groups. Each of these three groups occupies a different structural habitat which can be defined in terms of perch height and perch diameter. Within each of these three groups the species have very similar but not identical structural habitats but differ very widely in climatic habitat defined in terms of shade. Shade preferences seem to result from the temperature preferences of the species involved. In each group there is one species with high shade preference which is essentially restricted to the mountains. Each group also has a species with a lower shade preference which occurs in the lowlands and extends up into the mountains in exposed or sunny situations. One of the three groups has an additional species which is restricted to the hot arid southwest corner of Puerto Rico. When one compares the temperature preferences or eccritic temperatures of the various species, one finds in each group that the highland species has a lower eccritic temperature than does the lowland species. There is little temperature difference between the lowland species and arid southwest species in the group where this additional third species is present. The species within each structural habitat show many morphological similarities which may be the result of their being closely related or may be the result of adaptation to similar environments. The differences in microhabitat between the Puerto Rican anoles separate them spatially though not completely. In species occupying different structural habitats in the same area the overlap may involve part of the home range of most of the individuals in the area. In species occupying the same structural but different climatic habitats the overlap may involve all of the home range of some individuals but of only a small fraction of the individuals in the total population. The spatial separation among Puerto Rican Anoljs can be suggested to be of ecological significance because it reduces interspecific competition and because it allows the various species to adapt more precisely to different parts of the available habitat. Thus members of a genus may exploit the habitat more efficiently.