22 July 2016

Last Saturday fourteen of us joined purple martin landlords and their families at Bob Allnock’s annual Purple Martin Night where we learned about the birds and heard news of their success.

Purple martins (Progne subis) are North America’s largest swallow and the only bird that relies on man-made housing for its nest.  The western population still uses woodpecker holes but eastern purple martins made the switch long ago to nest colonially in apartments and man-made gourds provided by human landlords.

The landlords provide housing and protection and the martins return faithfully every year.  The dark blueish purple males arrive first — in April in western Pennsylvania — followed by the adult females with dark backs, light bellies and gray collars.  The adults claim their favorite nest sites before the speckled sub-adults arrive.

Purple martins eat only flying insects and are especially fond of dragonflies.  To catch them they feed higher in the sky than other swallows.  We didn’t think the martins were anywhere near us until we looked up at the clouds with our binoculars and saw them wheeling as much as 500 feet above.

By mid-July many of the young martins in Bob’s colony had already fledged but they still begged from their parents.   The (approx) 80 nest sites were humming with activity as the adults fed youngsters, took out the garbage (fecal sacs), and sometimes even tussled at the nest holes.  One youngster (see him in gourd #2) fledged while we were there.

Like all birds, purple martins are vulnerable to nest predation and a variable food supply. Fortunately they have dedicated landlords who …

• Check the nests to make sure all is well. In the slideshow notice the circular access lid on the gourds. Bob Allnock can also watch three nests on nestcams.
• Protect the nests from starlings by providing M-shaped holes that only purple martins can use.
• Thwart raccoons and snakes who climb the poles to raid the nests.  Bob Allnock has wrapped the base of his poles with live electric wiring (“electric fence”).  One shock is all it takes!
• Scare off great horned owls who raid from the air.  Bob turns on a yellow “air dancer” at dusk.  He moves it to a new location every night so the owls don’t get wise to it.
• Provide supplemental feeding during prolonged wet weather when the bugs don’t fly. Purple martins starve without these feedings.

And the weather has cooperated.  This year’s fledglings are doing well in western Pennsylvania’s dry weather, especially after three wet years in a row.

Until their young have learned the ropes the purple martins stay at the colony.  At dusk they return to spend the night inside the nests.

In September they’ll leave for Brazil and their landlords will wait through the long quiet winter for their faithful purple martins to come home.

Click on any photo in the slideshow to see it in a larger screen.

(All the purple martin close-ups are by Donna Foyle. House photos by Kate St. John.  Image of yellow inflatable air dancer from Amazon.com)

p.s. Sad news: Bob Allnock passed away suddenly on 12 Feb 2017.  He will be sorely missed, especially by fellow purple martin landlords and by his birds.