According to the Natural Events Calendar, this is the week when the year’s first purple martins usually return to Missouri after overwintering in South America. I haven’t seen any yet, but I’m going to be on the lookout now. There is a martin house on a pole not too far from my window at work. I usually notice the birds’ calls and then start looking for the source of the sound that I haven’t heard since the previous summer.
March can be a difficult month for the purple martin in Missouri because cold, rainy or snowy weather can limit the availability of their main food source--flying insects. Foul weather for several days in a row has been known to kill large numbers of early-returning birds. Some purple martin landlords (the folks who provide housing for them) will go so far as to place meal worms or other insects on the house porches to get them through a period of scarce food.
Purple martins seem dependent on humans for their housing, but they are also known to nest in tree cavities or in niches or cavities of cliffs, especially in the more western portion of their range. Before European settlement of North America, Native Americans provided gourds for martin nesting, as some folks still do today.
During the nesting period, one of the greatest threats to martins is competition for nest sites by the non-native house sparrows and European starlings. Also cavity nesters, those pest species will often out-compete the martins for available housing. Neither house sparrows nor European starlings are protected in Missouri, so their nests and eggs can be removed to discourage them from colonizing a martin house or gourd. Newer, commercially available martin houses often have entry holes that are designed to discourage the sparrows and starlings.
A common purple martin myth is that the birds consume large numbers of mosquitoes and serve their landlords by reducing local populations of those pests. Studies have shown that mosquitoes are actually a small part of the martin’s diet, probably due to the fact that martins feed during the day and usually feed higher in the sky where mosquitoes are infrequent. It is rare to see a martin on the ground, although they will occasionally land there to gather nest material. They do their eating on the wing and even drink in flight by skimming low over bodies of water.
To hear a recorded audio clip of the purple martin’s musical chirping, click this link. I hope you’ll soon hear it live.