The arrival of the cliff swallows to the Mission every March is world renowned. Swallows migrate miles from Goya, Argentina to San Juan Capistrano in large groups. Some cliff swallow colonies number more than nests.
The Barn Swallow, Hirundo rustica. The Barn Swallows use man-made structures to breed and consequently has spread with human expansion. This species lives in close association with humans, and its insect-eating habits mean that it is tolerated by man.