Though I saw my first purple martin (Progne subis) of 2010 in the middle of February (shortly after The Big Snow™), their return has been delayed this year as opposed to years past. Too cold, I suspect. But warmth has arrived in force and the martins have followed it north.
Like the barn swallows (Hirundo rustica) and cliff swallows (Petrochelidon pyrrhonota) who likewise have returned, these male purple martins are the vanguard for more to come. Perhaps a dozen of each species are here, give or take. They’re picking the best nest sites, establishing a pecking order, and filling the sky with the antics and sounds that speak of summer.
Unlike the western population of martins that nests mostly in natural cavities, the eastern population is almost entirely reliant on human-provided housing. It’s an interesting bit of behavioral adaptation that took only a short time to present itself. It began with martins nesting in food bowls and gourds and other structures provided by Native Americans. How that got started is anyone’s guess. But the birds liked it and the people liked it, so it continued.
Then when Europeans arrived, they fell in love with these majestic, dark creatures—and no doubt appreciated their high-volume insect consumption—so larger and more elaborate houses were built. The birds liked it and the people liked it, so it continued.
Over the span of 100-200 years, martins east of the Rocky Mountains had transitioned entirely to nesting in man-made housing. For the majority of the birds, that’s now the only way they’ll nest.
Despite rumors to the contrary, the eastern population of purple martins does not use human-provided nest facilities in response to competition from European starlings and house sparrows. Those birds were introduced long after the martins had come to rely on us for communal nesting structures.
(Their population did collapse after the introduction of starlings and sparrows, hence more intelligent home designs were created that would allow martins to enter the nest sites but would keep the starlings out. And education was important so those managing martin houses would know to keep sparrows out of the cavities and thus allow the martins a better chance at successful nesting.)
There are half a dozen martin houses within walking distance of my home. The native Blackland Prairie meadows along the eastern shore of White Rock Lake provide the right habitat and the plethora of insects these birds need to brood and raise young.
[As an aside, I just want to go on record as saying that the nitwit who decided martin housing should be white needs fifty lashes with a wet noodle for the photographic affront that creates. I realize the color helps reduce heat and therefore is good for the parents and the offspring, but still… Do you know how difficult it is to properly expose a picture of a nearly black bird when it’s posed against a bright white house? It ain’t easy!]