May was a blue month for purple martins
Cold and rain killed nestlings and adults across region
By KELLY BOSTIAN
For the CCOF
Anita Harp enjoys watching the busy lives of purple martins, but the view this May has been unlike any other.
Consecutive days of unseasonably cool, wet weather in the 40s and 50s grounded flying insects. That left the birds hungry and cold, and across Oklahoma, Kansas, and Arkansas, it’s likely that thousands perished.
“Purple martin landlords” like Harp, who might have a few or a few dozen martin birdhouses, reported on the carnage. They shared gruesome photos and discussed die-offs of both mature and young birds across private Facebook groups. Some reported a few chicks and adults dead, some lost several dozen, up to 70 in one case.
“Pinkies,” their word for featherless hatchlings, had it hardest. Landlords found dead chicks apparently the morning after they hatched.
“When you have multiple days in a row like that when it’s pretty chilly and drizzling constantly it really puts a burden on them,” said Dan Reinking, a senior biologist at the Sutton Avian Research Center, and the editor of the Oklahoma Bird Breeding Atlas. “The aerial insectivores are affected the most.”
Martins, known as the continent’s largest swallow species, have long relied on human hosts so they are watched closely. Others, like tree swallows, barn swallows, swifts and nighthawks also rely on flying insects for food.
Aerial insectivores, including certain birds and bats, are important wildlife species watched as ecosystem bellwethers. In recent years population concerns have grown with noticeable declines among insects, often attributed to pesticides.
Other insect-eaters like bluebirds, vireos, or warblers come to backyard bird feeders or hunt lethargic insects in trees or on the ground, but birds that feed almost exclusively on the wing got off to a rough start in May, he said.
13 birds in one house
The severity of the situation hit Harp when she checked on four 10-day-old chicks early this week. She could tell the adults were struggling to feed themselves, much less their young, so she brought supplemental foods to manually feed the young birds twice a day. She couldn’t believe what she found one morning.
“There were 13 adults in the one gourd with the four babies,” she said. “Adult males, females, and sub-adults, together? Normally that would be chaos, especially with babies in the nest. Because they were so stressed and trying to stay warm they had returned to communal gathering behavior.”
Early migrants sometimes gather in a single house like that to stay warm during spring cold spells. When mating and nesting begin the birds get territorial about their houses, she said.
“It was very odd to see that in late May,” she said. “When I saw 13 in tone gourd I knew I had to get the chicks out or they would be crushed.”
Tuesday through Thursday, she collected six dead adult females, one dead male, and 16 chicks that hatched only to immediately perish, she said. She took another dozen or so to a licensed wildlife rehab volunteer, who will raise and release the birds.
The four she pulled from that crowded gourd were so cold and lethargic she thought they would die, she said. However, a little time on a heating pad brought them around, and soon they were chirping for food.
Colonies will survive
With 111 active nests and some 580-eggs, the situation at her colony is not bad compared to others, she said. Although she still doesn’t know how many of those eggs still are viable, the colony will pull through.
“I have a big colony, so a lot of them will recover and it will come back. I’ve talked to a lot of people with their whole colony wiped out,” she said. “For me, it will probably be a year with lower numbers, but it’s OK as long as you don’t lose the whole colony.”
Reinking said June is Oklahoma’s busiest month for nesting. Most birds that lose their early nests will try again. For the martins, it means later hatchlings have to grow quickly for migration to South America, which starts in August.
“With all the rain and now temperatures getting back to normal I would expect a big flush of insects coming soon,” he said. “Something freaky could happen and we could have another cold wet snap and that could compound the problem, but if things get back to relatively normal most will have a chance to re-nest and will be fine with plenty to eat.”
Kelly Bostian is an independent journalist writing for The Conservation Coalition of Oklahoma Foundation, a 501c3 non-profit dedicated to education and outreach on conservation issues facing Oklahomans. To learn more about what we do and to support Kelly’s work, see the About the CCOF page.