Competitive relationships of the Common and Lesser Nighthawks

TitleCompetitive relationships of the Common and Lesser Nighthawks
Publication TypeJournal Article
Year of Publication1974
AuthorsCaccamise DF
JournalThe Condor
Date Published1974
Call Number00472
Keywordsarticle, articles, Aves, Chordeiles, bird, also SEE <AVES>, bird, Common Nighthawk, bird, competition, bird, diet, bird, Lesser Nighthawk, bird,distribution, journal, journals
AbstractThe study of competition and the resulting inferences, of necessity, have been often indirect. This is because the processes of competitions, as currently understood, are often quite ephemeral and subtle. On a basis of species interactions, there are three general situations for which competition often has been invoked as an explanation (Miller 1967): (1) the narrowing of a niche in sympatry (Lack 1944); (2) contiguous allopatry in the absences of environmental discontinuity (Miller 1964); and (3) character displacement (Brown and Wilson 1956; Hutchinson 1957; Mayr 1963). If these situations do indeed develop as a result of competition, then under certain circumstances their maintenance could require continuing competitive interactions. Thus such situations should provide the opportunity to study competition as a dynamic and vital process. Recent examples of studies performed under these conditions include Willis (1966), Brown (1971), Heller (1971), and Sheppard (1971). The distribution (fig. 1) and habitat relationships of the Common Nighthawk (Chordeiles minor) and the Lesser Nighthawk (C. acutipennis) are favorable for the study of factors involved with the competitive interactions of ecologically similar species. The two species are very similar in size, appearance, and general habits. The allopatric ranges of both species include habitats similar to those within the sympatric region. This combination provides a means of evaluating the impact of sympatry on the breadth of habitat utilization of both species. In addition, at several localities within the sympatric distribution, the habitat isolation breaks down, providing the means to study directly the competitive interactions between these species.