By: Susan A. Smith and James R. Hill, III, Executive Director, Purple Martin Conservation Association
Researchers at the Purple Martin Conservation Association (PMCA) have been studying a spectacular Purple Martin roost in Presque Isle Bay for ten years. The roost is located just outside the boundaries of Presque Isle State Park, on a pair of isolated cattail islands, tucked in the western end of Presque Isle Bay, near the port of Lake Erie. The PMCA estimates that from early July through early September upwards of 100,000 Purple Martins congregate nightly at this site.
These cattail islands (only 4.5 acres in size, combined) are not islands in the conventional sense of the word, as there is currently no dry land. The leaves of the plants are just densely-packed, emergent vegetation. The birds land on the leaves, matting them down horizontally, and sleep, side-by-side, very near the water of the bay.
For years, the PMCA and the local birding community have kept the exact location of this roost a relative secret and out of the news media, in hopes of protecting it from unregulated human visitation, potential development, and other unforeseen threats.
Recognizing the international significance and potential vulnerability of the roost location, the PMCA nominated the site as an Important Bird Area (IBA) earlier this year, and have recently received word that their nomination was granted. It is one of the PMCA’s most important accomplishments. Being designated an IBA will offer protection to this fragile roost located in the neck of the bay, an area popular with boaters, jet skiers, anglers, kayakers, and curious visitors.
According to banding studies conducted by the PMCA, this roost draws martins from at least a 250-mile radius, including birds from Ontario, New York, Pennsylvania, Ohio, and Indiana. The PMCA theorizes that Purple Martins are attracted to this site for at least three reasons. First, because of nearby Presque Isle State Park with its natural wetland habitats and superabundance of flying insects, allowing the birds to fatten up prior to their migration to South America. Second, the isolated cattail beds are a safe place for large concentrations of martins to sleep away from terrestrial predators. And finally, because the shallow bay waters are a huge heat sink, absorbing heat during the day and staying 30-40 degrees warmer than surrounding night air. Martins roosting on the cattail islands, within inches of the warm waters, are able to conserve valuable energy.
The PMCA is very pleased to have secured IBA status for this significant roost. Conserving the site will have direct benefits for martins, and will help preserve the state’s biodiversity as well as this fragile ecosystem, which is also used by waterfowl and marsh birds and a variety of swallows. By focusing attention on the most essential and vulnerable areas, the Important Bird Area Program promotes habitat conservation. While not all martin roosts will qualify for IBA status, some will. We encourage martin landlords throughout North America to assist in identifying, monitoring, and, if appropriate, nominating roosts in their area for IBA status. Please contact the PMCA (www.purplemartin.org) and/or your state Audubon office for assistance.
The following criteria are used to select IBA sites: