The last pair of purple martins nesting in the gourds at Grand Haven State Park may have a tough time getting their young ready in time for the flight south to the Amazon rainforest.
Owastanong Islands Audubon Society member Dave Herdegen, a purple martin landlord and a Grand Haven Township resident, was surprised to see any birds in the white gourds located on a pole on top of a small dune by the south pier.
“They’re a couple of weeks behind schedule,” he said as the dark male and the female with the light-colored underbody flew circles around the gourds before entering with a dragonfly meal for their young. “A month ago they were here like crazy. Now they are starting to get ready for their trip to Brazil.”
Herdegen explained that the young birds had to develop into strong flyers and take in a lot of food before starting the trip south.
The purple martins usually arrive in mid-April, but came a few days early this spring, likely because of global warming, Herdegen said.
Ferrysburg and Grand Rapids resident Rick Briggs agreed that climate change may have resulted in an earlier arrival, but he had his martin houses ready to go.
“A male scout usually shows up between April 7 and 17,” Briggs said. “Once he shows up, we get the house ready.”
That means attaching the pole on a platform he puts in front of his home on Spring Lake. He lines the bottom of the houses with pine straw and the purple martins will fill it the rest of the way with leaves, twigs and mud, Briggs said.
Once you put up the gourds or houses, you have to be prepared to check them regularly to make sure invasive birds don’t take over the compartments. That’s why you need the types of birdhouses that can be raised and lowered with a pulley.
“It’s a full-time job keeping the sparrows out,” agreed Briggs’ wife, Sharon.
Herdegen said he checks the gourds by the south pier and the gourds and houses on the north pier at least once a week until the purple martins vacate for the winter. If an invasive bird – such as a sparrow or starling – attempts to make a nest, then he removes the bird and the nesting materials to keep the unit open for the purple martins.
The Owastanong Islands Audubon Society owns the houses on both sides of the channel.
“Our club bought these gourds 20 years ago,” Herdegen said, pointing to the cluster mounted on a pole on top of a small dune next to the south pier. “We had difficulty finding a good place to put them.”
Herdegen said after moving them around without success, they finally received permission from the Michigan Department of Natural Resources to place the pole on top of the dune a couple of years ago. This year, all 12 gourds were populated and each pair of birds produced an average of five young, Herdegen said.
On the north side of the channel, in the houses donated to the club by Herb DeJonge, there are 44 houses with more than 200 birds, he said. That’s where ornithologist Brian Johnson banded 90 birds on July 7, Herdegen said.
Anybody who finds a band can go online to the Bird Banding Laboratory on the United States Geological Services website: reportband.gov. This site will tell you when and where the bird was banded, as well as other information, Herdegen said.
Purple martins used to nest in holes created by woodpeckers, but as more and more land has been developed, the birds have come to depend on humans to provide nesting for them.
“They like humans,” Herdegen said. “They like being around farm yards and beaches.”
Briggs agreed, noting the reason he placed his birdhouse out in the lake was to give the purple martins room to freely swoop around before landing on their perch. They also need to be within a couple miles of water, he said.
While Briggs has had success in the 14 years he has cultivated the graceful birds, Herdegen said others have not been so lucky. That’s why he is so excited about the birds populating the houses on the north and south sides of the Grand Haven channel.
It’s gotten to the point where the birds are starting to repopulate houses up the river, Herdegen said. As an example, the birdhouse by the U.S. Army Corps of Engineers office had sparrows in it up until last year when the purple martins took over again.
“It’s an overflow from here,” Herdegen said. “We’re like an incubator here.”
Briggs, who has a zoology degree, said he has always been interested in the biology of birds. His specific interest in the purple martins started when he went to a store to buy some birdseed and saw the martin house. He was recovering from chemotherapy, so “putting together the house gave him something to do and was good therapy for him,” Sharon said.
He’s been doing it ever since and it’s kept him very busy, Briggs said.
“There’s a lot to learn to be a good purple martin landlord,” Herdegen agreed. He encouraged people to check the Purple Martin Conservation Association website at www.purplemartin.org. This is also where people can check scout reports to see when it’s time to raise their birdhouses.
Herdegen said it’s important not to set up the houses too early or the sparrows will use them.
Purple martins have been a beloved bird species, Herdegen said. People appreciate the activities of these unique birds as they live and forage from an active colony. Being colonial nesters, there is a lot to watch as many birds interact from the colony site. There are spring arrivals from Brazil, pairing up, nest box selection, nest building, egg laying, hatching, feeding, fledgling (first flight) and fall migration.
“Everyone appreciates the thousands of flying insects that a colony will devour in flight, as they swoop and dive,” Herdegen said.
These birds prefer dragonflies and flying spiders, Briggs said. The purple martins are already bedded down for the night when the mosquitos make their appearance and are followed by hungry bats.
Herdegen said many purple martin colonies have experienced failures in the past few decades. Two invasive species have been jeopardizing the success of the human landlords trying to maintain colonies. Aggressive house sparrows and starlings from England have been taking over prime housing, leading to colony collapse.
Advancements have been made in housing design and, along with active human management, colony success can be improved, Herdegen said. Housing that can be lowered vertically is used by the landlord to do frequent nest checks to look for and mitigate problems. A new entrance hole design has been successful in limiting European starling access.
Briggs said the outward appeal of the purple martin is its soaring approach and beautiful song.
Briggs said the last purple martin left the nest in front of his home on Aug. 10. He gives the birds a couple of weeks to make sure they are gone for sure before he takes the house down, gives it a thorough cleaning and puts it away until next April.