I made a mistake! A few days ago Leonard and I saw a pair of purple martins (Progne subis) at a woodpecker hole in a ponderosa pine (Pinus ponderosa) snag near Crystal Lake (Shasta County CA). We were excited because we rarely see purple martins, the largest swallow in North America, nearby. A male and female were working the hole and appeared to be building a nest. After halfheartedly snapping a few pictures Leonard and I headed home. We were tired after a long day and I believed when we returned to the site later in the week I could spend the time to get good photographs. Wrong!! Three days later the hole appeared abandoned and no purple martins were to be found anywhere nearby.
Purple martins are found throughout the East, in the Rockies and along the Pacific Coast. In the East purple martins are colonial and nest almost exclusively near human habitation in nest boxes or “apartment houses” constructed specifically for martins. In the West martins are more likely to be solitary and nest almost exclusively in abandoned woodpecker holes or other natural cavities. Introduced European starlings and house sparrows, as well as woodpeckers and other birds, will compete with purple martins for nest cavities with the martins most often departing to search for other nesting sites. While watching and photographing the martins, I noticed an acorn woodpecker (Melanerpes formicivorus) harassing the pair. Perhaps that woodpecker discouraged the purple martins from using the hole. Whatever the reason, the martins were gone. I should know by now that with wildlife there might not be a second chance. (This snag was an acorn woodpecker granary. Note all the empty holes where acorns were cached by the woodpeckers for the winter. A few of the holes still had visible acorns.)
Purple martins have a short, forked tail, long, tapered wings and a heavy bill with a slight hook at the end. Male martins are an iridescent dark purple/blue overall with brown wings and tails. Females are dusky grey with a whitish lower belly and varying amounts of glossy purple on the crown and back.
Aerial insects comprise the entire diet of a purple martin. Martins get all their food in flight, including water. A purple martin will skim along the surface of a pond or other water source and scoop up water with its lower bill. They rarely land on the ground, only doing so to collect nesting material or bits of grit to help grind up the exoskeletons of their prey.
Since purple martins only eat flying insects, they are particularly vulnerable to cold or rainy weather because there are no (or not enough) insects in the air for the martins to eat during those periods. After a few days of bad weather purple martins are subject to starvation.
Purple martins are long distance migrants that breed in North and Central America. Bolivia, Brazil, Argentina and other parts of South America are their winter destinations.
Leonard and I were so happy to see a pair of purple martins that I am going to share their pictures – even though the pictures could be better. Maybe next time I will remember to take full advantage when opportunity presents itself.