The Bank Swallow (Riparia riparia) nests in a burrow excavated in a sharply-sloped sandy embankment. These fascinating swallows may be found nesting in the cliffs that line the Mississippi National River and Recreation Area in the vicinity of Hidden Falls Regional Park and other locations within the Mississippi Gorge Regional Park. These cliffs are formed from poorly-cemented St. Peter sandstone which is soft enough that these birds can excavate nest burrows.
Bank swallows are obligate colony nesters, meaning they always nest in colonies. Nesting in colonies may provide additional protection from predators as there are many eyes watching for danger and the birds can mob predators that get to close to the nest. Colonial nesting also may permit birds to find scarce resources by watching each other.
But there also are disadvantages to colonial nesting. Large masses of birds wheeling over the river may also attract the attention of predators large enough that mobbing won't drive them away. Colonial nesting also may increase the prevalence of disease and parasites within the tightly packed nest sites. There are also relatively few good nesting sites close to good feeding areas.
Fascinating Facts
Swallows have small bills and large mouths that are well adapted to catching flying insects while the bird is on the wing.
The swallows' long, pointed wings and squared off tails provide great maneuverability as they wheel and dart after elusive flying insects.
