Comparative Nesting Ecology of the Eastern Phoebe (Sayornis Phoebe) and Says's Phoebe (Sayornis Saya) in West-Central Kansas

The nesting ecology of the Eastern Phoebe and Say's (Sayornis phoebe and S. saya, respectively) was compared during the 1973 and 1974 breeding seasons to determine the factor (s) that might limit their distribution in a sympatric area in west-central Kansas. The study area, Ellis County, includes the extreme breeding range for both species. Overall density of Eastern Phoebes is low (one pair per 26,000 acres) because of a paucity of riparian woodland. Results of field observation and censusing suggest that the density of Say's Phoebes is comparable to that of Eastern Phoebes. Eastern Phoebes were restricted to bridges in riparian areas; Say's Phoebes selected a variety of structures as nest sites throughout open rangeland and farm land in this area. Only one pair of phoebes occupied a given nest site; therefore, they are obviously territorial. Because foraging areas did not overlap, inter-specific hostility resulted in competition for nest sites (bridges) in intermediate habitat. However, densities were low and territorial or competitive interactions were rare events. This study suggests that for the Eastern Phoebe, the only obvious factor limiting the breeding range to the west was a decrease in suitable habitat; competition, as a limiting factor, seems to be of little importance. It appears that the same is true to the east for the Say’s Phoebe.