I recently received an e-mail from Janet Foltz, who had read my story on the life history of martins. She said they were able to attract the birds to a house in Chanhassen and was entertained by their wonderful antics.
The family now lives on Lake Nisswa and wonders if others in the area have been able to attract purple martins to their yards.
In October I heard from Kelly Applegate of Princeton, who's a member of the Purple Martin Conservation Association in Edinboro, Pa. She's studied local purple martin colonies in upper Minnesota for several years and provided the following information about dwindling populations of martins in that area.
Older martins in an established colony return to Minnesota as early as mid-March to claim nest compartments before younger martins arrive. When older martins get here the weather often is cold and they die of starvation. Cold weather equals no insects, the mainstay of martins' diets. Dedicated martin landlords will keep crickets handy (fresh or frozen) to feed the birds in these situations. The martins are confused at first, but quickly take to catching the crickets in of the air, showing trust. They might even land on the person throwing the crickets!
When the weather warms the martins begin their next challenge: dealing with nest-site competitors, including the English sparrow and the European starling, two non-native birds that peck holes in martin eggs, tear apart their nests, kill adults and hatchlings and spread disease to the colony. Martin landlords trap and kill English sparrows and the starlings, as they aren't protected species.
Another effective method for discouraging starlings is to build crescent-shaped, starling-resistant entrance holes in martin houses. They allow martins in but exclude starlings. The configuration is the current norm in modern purple martin colony management. Kelly said it's a miracle when martins live long enough to hatch their young and rear the newborns.
Predation is another obstacle to overcome. Great horned owls are a silent, deadly enemy of purple martins. They sit on martin houses at night and listen for activity. When owls hear martins shifting about they sometimes reach into the house and grab the helpless birds. Raptors beat their wings on houses to flush martins out and grab the birds upon their escape.
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