Authors’ Response

In their paper reporting the interspecific aggression of a Blue-throated Hummingbird (Lampornis clemenciae) toward other species of hummingbirds, Lyon, Crandell, and McKone (Auk 1977, 94: 448454) contend that their observations contradict a basic assumption of my model of interspecific territoriality (Ecology 1971, 52: 414-423). This is not so, and, because their paper is likely to be cited as a test of my theories, it seems best to correct the misinterpretations at this time. In my 1971 paper I made the following predictions: assuming that interspecific territoriality is misdirected intraspecific aggression, (i) cases of mutual interspecific territoriality should occur only between allopatric species where their ranges abut and between sympatric species occupying different habitats, and (ii) species that are widely sympatric and occupy extensively the same habitat(s) should differ in their territorial behavior or differ greatly in size. Further (p. 421), assuming that individuals would benefit by recognizing and excluding from their territories members of other species, (iii) one species should be aggressive toward a second interspecifically non-aggressive species, which is excluded from habitat(s) it would otherwise occupy. Evidently, a Blue-throated Hummingbird responded differentially to other species of hummingbirds, suggesting that it was able to distinguish species. Lyon et al. do not report any aggression by the other hummingbird species toward the Blue-throated Hummingbird, and they suggest hat in natural situations "probably all species of hummingbirds are excluded from Blue-throated territories with equal efficiency" (p. 453). As reported, then, the observations of Lyon et al. seem consistent with my prediction (iii).-BERTRAM G. MURRAY, JR., % Biology--Livingston Rutgers University, New Brunswick, New Jersey 08903 USA.