Both Great Horned Owls (Bubo virginianus) and Cave Swallows (Hirundo fulva) occur in the caves of southeastern New Mexico, but no interaction between the two species had been previously recorded.
On 1 June 1984, Tom and Bobbie Bemis, Ron Kerbo, and I visited Ogle Cave in Slaughter Canyon, Carlsbad Caverns National Park, Eddy County, New Mexico, to check on the approximately 100 Cave Swallows nesting there. As we rappelled into the cave, we flushed a Great Horned Owl, which was mobbed by Cave Swallows as it left the cave.