Reports of cave swallows in southern Maine recently have stirred the birding community.

“Be on the lookout for these. This was a first record for Maine,” wrote Fields Pond Nature Center director Judy Markowsky in a Maine birding e-mail post.

I realized how unusual this was when I looked at a map of this bird’s normal range, which includes South America, Texas, the very southern tip of Arizona; the southern tip of Florida and the Caribbean.

It’s not impossible for a bird to show up far from its regular haunts; it does happen at least a few times each season, especially when powerful storms blow the birds off-course. This may be why these swallows have appeared so far north at this time of year.

The cave swallow resembles the cliff swallow, which breeds throughout much of North America; however, there are some differences in plumage patterns and coloration. It is generally lighter in color around the cheek, neck and throat area than the cliff swallow. It’s easy to see these differences if the bird is perched quietly, of course; in flight it takes an expert eye to tease out the details.

The “Birds of North America” species account reports this swallow has greatly increased its range into Texas and has colonized Florida since the mid-1980s, indicating it has done well. As its name suggests, the swallow historically nested in caves or sinkholes. It still does, but has expanded its options for nesting by using human-made structures – culverts, bridges and on the sides of buildings, as does its relative the cliff swallow.

Because this bird often nests in caves, it shares its living space with bats. They largely avoid one another, as bats are active by night, after the swallows have come in to roost.

Such is not always the case, however.

I was amused to read about bird-bat encounters in the BNA, which stated, “swallows generally roost before the bats exit, but sometimes a few swallows are still outside; when this happens… they fly into the cave, hugging the sides of the walls or trying to make their way through the bats… collisions are rare but do occur… [most are] apparently not fatal or harmful to either species.”

While our visitors in southern Maine may not have to worry about navigating through a mob of bats, they do have a more pressing need: Food. The mild spells we’ve been having may have caused enough insect activity to keep them fed, and to fuel them for a flight home to South America. Let’s hope they make it back.

NEWS bird columnist Chris Corio can be reached at bdnsports@bangordailynews.net