Recent information suggests that Cliff Swallows are decreasing in Maine. Consequently, Cliff Swallows are listed as Species of Greatest Conservation Need in the Maine Wildlife Action Plan. Although likely due to a culmination of many issues, the loss of nest sites to invasive species have been identified as a contributing factor to this species’ decline in other regions of the country. Fortunately, recent studies have revealed that Cliff Swallows will readily make use of artificial nests when provided at existing and historic colony sites. These artificial nests can be maintained to prevent use by invasive species while also providing suitable nesting sites year after year.

Cliff Swallows are vulnerable to threats like pesticide pollution and competition with invasive European House Sparrows. Although highly tolerant of humans, their willingness to form colonies on or near human structures can result in conflicts ending in their eviction. Understanding the issues which negatively impact this species will require a better understanding of the species’ distribution during the breeding season and their breeding behavior at nesting sites.