Monday, June 9, 2014

Purple Martin

On 4 June 2014, John Holden came upon a pair Purple Martins on a dirt road in the village of Warsaw, Minnesota. This behavior is reported for this largest of North American swallows. Tarof and Brown (2013) write that martins use fine bits of gravel to help digest insect exoskeletons. Martins do not feed in flocks, but often in pairs—the result of mating-guarding by the males.

Martins consume dragon and damselflies as well other arthropods. such as beetles, bugs, flies, grasshoppers, butterflies and moths (and their caterpillars), wasps and bees, and even termites. I have previously written about martin diets. Tarof and Brown report that no credible data exist that Purple Martins eat mosquitos, despite the popular belief to the contrary. For one thing, martins tend to feed high in the air (sometimes up to 450 feet), whereas mosquitos stay near the ground.

I also wrote about Purple Martin range. Since that post, some fascinating research with geolocators has appeared, as reported in the Forest Lake Times. Here you can find maps of routes taken by two Minnesota Purple Martins to the Brazilian Amazon Basin. One bird flew over the Gulf of Mexico and down through Central and South America and returned by the same route. The other took the same path north in the spring, but, during the fall migration, visited the length of Cuba before continuing to Brazil.

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