Above: Mission ruins, San Juan Capistrano, California, c. 1962

From Wikipedia:

When the swallows come back to Capistrano
That’s the day you promised to come back to me
When you whispered, “Farewell,” in Capistrano
’twas the day the swallows flew out to sea

— excerpt from “When the Swallows Come Back to Capistrano” by Leon René

In recent years, the swallows have failed to return in large flocks to the Mission.  Few birds were counted in the 1990s and 2000s. The reduction has been connected to increased development of the area, including many more choices of nesting place and fewer insects to eat.