• coloniality;
  • conspecific attraction;
  • fitness;
  • Nebraska;
  • Petrochelidon pyrrhonota;
  • social behaviour


1. One way that animals may select breeding sites is by assessing the reproductive success of conspecifics in one season and settling the next year in those habitat patches where success collectively had been greatest. This sort of habitat assessment may promote the formation of colonies at high quality sites.

2. We examined whether cliff swallows, Petrochelidon pyrrhonota, in south-western Nebraska used conspecific breeding performance to choose colony sites.

3. Reproductive success at colony sites varied spatially within seasons and between seasons, and was autocorrelated at a site from one year to the next, but not over longer time intervals. Cliff swallows thus met the conditions for potential use of information on conspecific breeding performance.

4. Among sites re-used in consecutive years, those with highest collective success in one season showed the greatest rates in colony growth the next season, including the greatest influx of immigrants.

5. The probability of colony-site re-use in successive years increased with collective reproductive success and average breeder body mass (a measure of individual condition) the previous season.

6. Cliff swallows probably use conspecific breeding performance in selecting colonies. This mechanism is one component of habitat selection that also includes attraction to conspecifics and assessment of an individual's own success.