Summary To minimize study‐area artefacts in a study of natal dispersal distances in tree swallows, we intensively banded nestlings and adults in nest‐boxes in upstate New York and recruited and trained 70 volunteer banders within a 400 km radius of Ithaca. We banded 26 567 nestlings in the years 1985 through 1998, and captured 4774 adults at the nest, 630 of which had been banded as nestlings and were recaptured the year after fledging. To correct for spatial variation in capture intensity, we resampled the distribution of all boxes where an adult capture was made under uniform, exponential and Cauchy null hypotheses. Compared to the null distributions, the frequency of observed dispersal events was significantly higher at 0–10 km and lower for all larger dispersal distances. The Cauchy distribution came closest to approximating the observed dispersal distance distribution. Dispersal distances were sensitive to the distribution of nesting sites, and all measurements of dispersal distance distributions must be seen as being habitat‐specific. We could detect no effect of dispersal distance on the subsequent timing of breeding and no effect of the timing of fledging on dispersal distance. The sexual differences in raw mean dispersal distances (8·38 km for females, 2·44 km for males) are similar to those reported for other species. While it is tempting to conclude that studies in smaller areas have not missed a great deal, even a study area of 10 km extent (substantially larger than most) would have missed 11% of the dispersing birds detected and 95% of the range of distances recorded. Despite this sizeable component that would have been missed with a smaller study area, the relatively low frequencies of long‐distance dispersal overall reinforce the conclusion that tree swallows, and probably most other migratory passerines, generally disperse much less far from their natal sites than the distances of their annual migrations might lead one to expect.

To study the patterns and determinants of philopatry and breeding dispersal in the Tree Swallow (Tachycineta bicolor) we analyzed the records of 356 males and 1459 females captured in more than one breeding year around Ithaca, New York. Of these captures, only 4% of male and 14% of female breeders dispersed to a new site for breeding. With our combination of intensive study areas in Tompkins County, New York, and the efforts of volunteer banders throughout New York and surrounding states, we could have detected dispersal in excess of 400 km from the initial breeding site. Randomization tests revealed, however, that breeders dispersed much shorter distances than they could have been detected. Detailed analyses of recaptures in Tompkins County showed that over a 22-km range of distances, the chances of dispersal to a new breeding site declined with the distance from the original breeding site. Females that failed to fledge any offspring were much more likely to disperse than females that reproduced successfully, and the probability of dispersal declined gradually with female age. The spatial scale in which swallows gather and process information appears to be much larger than for passerines that defend all-purpose territories.