Michael -

Northern Rough-winged Swallows, as opposed to Bank Swallows, don't dig
their own nesting holes. They use those dug by someone else, Bank
Swallows, Kingfishers, drainpipes, etc. Along with some other hole
nesters who do not dig their own holes they tend to be early arrivals,
probably to try and gain an advantage in finding holes. This would
require defending the hole against other potential owners,including
previous ones. They would seem to be at a disadvantage if choosing a
Kingfisher burrow. Thanks for the observation.

Brian H. Bell
Woodinville Wa
bellasoc at isomedia.com