birds seen while in flight

  1. DaveW

    A question for pilots flying into tropical Mexico or points south

    I study a species of large swift (like a swallow, but more aerial) that nests in colonies of tens of thousands in huge caves in Mexico (and south to northern Argentina). My biggest study colony is 100 miles or so due west of Tampico. 50,000 swifts (larger than a Mourning Dove, black, and...