Written by Cheryl Conley, TWRC Wildlife Center
If you provide “rental property” for Purple Martins, then you know it’s time to clean out your houses to get ready for their arrival.
The first Martins to arrive are referred to as the “Scouts” and they are the oldest birds. Older females arrive next followed by the younger birds. Martins will return to the same colony site where they resided the previous year. Once they arrive, nest-building will begin in 4 to 6 weeks. They use twigs, pine needles and straw. Once the nest is complete, they add a layer of green leaves. Ornithologists can only guess why they do this but think the leaves may act as an insecticide, may help keep the nest clean or help regulate the temperature and moisture levels. The female lays one egg per day for a total of 2 to 8 eggs. In about 15 days, the eggs begin to hatch which can take 2 to 3 days. Babies are fed up to 60 times a day by both moms and dads.
It takes 2 years for Martins to acquire their full adult plumage. Purple Martins aren’t really purple. Mature Martins are a glossy deep blue—almost black-looking. They feed mostly on flying insects and can eat thousands of mosquitoes in a day. They catch most of the insects in mid-air and even drink water from ponds, lakes and streams while flying.
If you’ve never had a Purple Martin house and you’d like to get one, there are some things you need to know. You’ve heard realtors talk about “location, location, location?” As a Purple Martin landlord, this holds true as well. They prefer large, open areas where the nearest building is a minimum of 30 feet away and from 25 to 60 feet away from trees. Make sure your house is secure and doesn’t spin around when it’s windy out. The birds can become disoriented.
You may be lucky and get renters your first year. Sometimes it takes a couple of years for them to discover your house. There are a couple of things you can do to increase your success. One website I checked suggested playing Purple Martin vocalizations near your Martin house very early in the morning. There are several recordings on YouTube. You can also place life-sized black decoys on your house. If you have a large house with several compartments, you can construct a fake nest in one of them. Don’t forget to put green leaves on the top of the nest.
You should protect your Martin houses with predator guards. You can purchase owl and hawk guards. Predator baffles, or pole guards, will help keep snakes and raccoons from climbing the pole.
In late fall, you can take your Martin house down and put it back up when the Martins return in the spring. The other option is that you can leave it up but make sure you clean it well and block the entrances so other species of birds don’t move in. Remove the blockages in spring when the Martins return.