The purple martin, known for its chattering song, and aerial acrobatics, lives in colonies but relies on human-made nest boxes to breed in the eastern US. The population in Pennsylvania has dropped by nearly two thirds over the past 50 years. But the Purple Martin Conservation Association, an international group based in Erie, Pa., is working to save the species.
The Allegheny Front’s intern, Jack Austin caught up with Joe Siegrist, president and CEO of the association as he was checking one of their colonies at Presque Isle.
LISTEN to their conversation
Joe Siegrist: So we’re going be lowering down the house. It’s on a winch cable system on the aluminum pole that it’s mounted on. That’s an important feature of any purple martin housing. [It] should be able to be lowered so you can keep aware of any conditions that may arise in the nest.
If you have evidence of predators or issues that may arise, it’s helpful in keeping the invasive species out. You can lower the housing down and remove it.
But as you can see, we can lower the housing down and get hands on the birds here. Let me grab one of these. So these are just about old enough to fly. You can see the leg bands that we’ve put on it.
Every year we [band] between 500 and a thousand birds here at our four research colonies on the park. Our total is probably 30,000 purple martins over the over the years that [the association] has been banding.
Jack Austin: So purple martins in the area have faced loss of habitat. What are the main sources of that loss?
JS: Purple martins are suffering from a lack of nesting habitat. Traditionally, they would have nested in secondary cavities which are woodpecker holes and holes in rock piles and cliffs.
Over time, we have fewer forested areas and fewer standing dead trees to house those woodpecker holes. One of the major factors [for their decline] is the introduction of two competing species from Europe: the English song sparrow and the European starling, who out-compete purple martins for the remaining cavities.
JA: Purple martins almost exclusively breed in human-made bird houses like this. Why is this?
JS: It’s really been a saving grace for them. The tradition of purple martin nesting and human-provided housing began before European settlement, with Native Americans. They began hanging up hollowed out gourds in their villages. We don’t really know why [Native Americans did this], but purple martins began nesting in them. This symbiotic relationship began at that point between humans and purple martins. Lucky for the martins, that mechanism was already in place for them as their natural habitat declined and those invasive species took over.
“People are the only thing standing between this species that eats billions of insects every year and their extinction in the eastern part of their range.”
JA: You mentioned that you teach members how they can set up their own martin colonies. Do people need a special background?
JS: It’s surprisingly easy. A lot of folks mistakenly think that you need to have a pond right near where you put up purple martin housing. That’s really not the case. They get a lot of the water that they need from the food that they eat and they also travel miles and miles every day in their search of food. So, they’ll find some water.
You just need to provide the housing and really the key is to have an open area. They don’t like to be around tall trees. They see that as a risky situation because their major predators are hawks and owls which use those trees as hiding places and easy access to the purple martin colonies.
JA: So once one of these bird houses goes up, what type of maintenance is required?
JS: The only required maintenance is to make sure that you don’t allow those invasive species that are the sparrows and the starlings to establish nests in the housing. They will either prevent purple martins from colonizing that area or if you already have purple martins and you allow those species to nest, they will kill adult purple martins and babies.
JA: What is the organization researching right now?
JS: The most exciting one that we have going on right now is our migration research that takes us down to Brazil. The recent advances in technology are devices called biologgers, basically they’re a little computer chips that have G.P.S. onboard and they record locations.
In the last few years, we’ve been attaching these devices that weigh less than a gram to purple martins and they migrate down south. For the first time ever, we’ve been able to get an idea of where they are in Brazil, what type of habitat they’re using, what they’re encountering to get a broader picture of all the things that are affecting purple martins.
JA: How has climate change affected purple martins?
JS: They’re one of the first birds back in the spring. They’re particularly vulnerable to late cold weather because they are aerial insectivores. They only eat flying insects and if it’s cooler than 50 degrees or so outside, there are no insects to be seen. As the climate is changing, those spring and fall weather cycles are much more unstable and unpredictable.
These birds have thousands and thousands of years of evolution that have told them they need to be back at this time every year. Now the conditions in that time have changed, where they may come back and freeze to death. They may come back and starve to death.
There’s some really critical research that we’re conducting to see if they’re going be able to be flexible enough in their timing to survive, particularly in the northern parts of the range, as the climate is changing.
JA: How often do you get out here?
JS: Well, now that I’m the boss, not as often as I would like to. You know, it’s a pretty great office to have, to be able to come out here and just hang with the birds. I mean Presque Isle’s great. We’ve got the lake. You can hear the waves crashing in the distance here. Yeah, it’s not a bad gig.
And you know just give these birds a chance because people are the only thing standing between this species that eats billions of insects every year and their extinction in the eastern part of their range.