Too much human interference causes some to abandon their nests, and with breeding success on the line to help increase the local eastern populations, any nest failure is devastating. I saw for myself just how humans being too close impacted them. While out birding near one of the colonies, I witnessed a couple playing with their dog just feet away from the nest poles and saw how quickly the birds flew off chirping their alarm calls. They were unable to return to their nest boxes until after the people and the dog left. I myself made the mistake of being too close while photographing terns fishing from the pond near the site. In reporting this observation to members of the local Audubon chapter, ropes were installed with signage asking folks to respect the birds and to keep their distance.
To learn more about the Purple Martins and what you can do, check out the links below. Consider becoming a landlord or giving the gift of being a landlord to someone you know who loves nature.
Purple Martin Conservation Association www.purplemartin.org
Menunkatuck Audubon Purple Martin Landlord Program martinlandlords.weebly.com/purple-martin-basics.html
All About Birds Purple Martins www.allaboutbirds.org/guide/Purple_Martin/lifehistory
Attracting Purple Martins www.purdue.edu/wildlife/homeowners/backyard/martins1.pdf