By Mickey Dufilho
The Purple Martin’s annual cycle is very predictable. Unless there is unusual inclement weather such as freeze or tropical storm, the birds arrive, establish their territory, build a nest, lay eggs, and hatch, fledge and depart like clockwork. So why did they ignore our wonderful martin house for so many years? We thought we did everything correctly. In our effort to attract the martins, we moved and erected the martin house a few times as trees grew and encroached on their aerial space requirement. They prefer an open area of about 40 – 60 feet away from structures and trees, and the house height of 15 – 20 feet. As a landlord, it is important to have easy access to the house by placing it on a pole that allows it to be raised and lowered for housekeeping and to close up the holes for winter. In January, martin scouts begin to arrive in our area, so we opened the martin house holes as directed. It is important to be vigilant during the next few months, to remove nests of House Sparrows and starlings that try to set up housekeeping in the martin apartment. Oops, we may have slipped on this task. There will be little success if these aggressive birds are allowed to claim any space in the house. It will be necessary to lower and raise the house weekly to discourage these pests from nesting. Weekly? We missed that point too.
In our resource folder I found other issues that impact nesting and we have not considered any of these. To keep climbing predators away, we need to install a predator guard on the pole and to keep owls, crows and hawks away, we need to figure out what an “owl guard” is and place in the holes. An issue in which we have no control, but can significantly impact our martins’ success is the weather. Although we do not have prolonged bad weather in our area, a storm that keeps winds high for 2 to 3 days or extreme drought could reduce insect flight and would be devastating to the martins. Temperatures above 100 degrees can kill nestlings. Fortunately most of these events occur later in the martin breeding season after they finished breeding and are gathering up for migration.
My brief research has given me a few ideas on how to solve the puzzle of why it has taken 18 years before the Purple Martins have shown any interest in our old martin house: put the house in a good location the first time and try not to move it several times. Moving the house confuses the birds from one year to the next. Put barriers in place to keep out predators. Practice good housekeeping. Monitor the box weekly for problems. We cannot do much about the weather or insects, but if we start this summer, we will have “time” to get things ready for next season and become better landlords. As we and my friends at the Gulf Coast Bird Observatory have learned, patience is key to being a successful Purple Martin landlord.
For more information on attracting and managing Purple Martins, see purplemartin.org or Cornell Lab of Ornithology at birds.cornell.edu.