What is the Purple Martin?
The Purple Martin (Progne subis) in a very unusual swallow in the family Hirundinidae and order Passeriformes. It is a beautiful bird that subsists on insects, flying through the air catching them on the wing.
Unlike other swallows in North American like the Tree Swallow and Barn Swallow, the Purple Martin has been harder hit by habitat modifications by humans such as the introduction of the House Sparrow and European Starling and also by newer building construction with fewer crannies . Most birders will be familiar with the latter two birds. The House Sparrow (Passer domesticus) for example has a native range in Europe and western Asia and has invaded places like Canada, United States, South Africa, Jamaica, and Australia. The European Starling has a similar invasion story.
Today you will likely find Purple Martins in special nest boxes set up by humans. These have to be maintained and if you go see one, you’ll likely see House Sparrows trying to take them over. In North America, there is the Purple Martin Conservation Association that is probably the best place to start if you want to set up a nesting site for Purple Martins.
The Purple Martin breeds in colonies and collects nest material about a month before eggs are laid . Since Purple Martins depend on insects as their food source, weather fluctuations causing insect population fluctuations are known to cause population instability , and this is the part of the reason Purple Martin colonies need so much maintenance.
 Cousens, Bruce, et al. “Two decades of purple martin stewardship and recovery in British Columbia-successes and challenges.” Proceedings of the 2005 Puget Sound Georgia Basin Research Conference, Seattle, Washington. 2005.
 Johnston, Richard F., and John William Hardy. “Behavior of the purple martin.” The Wilson Bulletin (1962): 243-262.
 Finlay, J. Campbell. “Some effects of weather on Purple Martin activity.” The Auk (1976): 231-244.