What is a Martin Roost? In late Summer, after leaving the nesting colony, Purple Martins gather in large flocks to feed, socialize and rest before migrating. This activity, known as pre-migratory roosting can attract thousands of birds to one small area. Martins also form winter roosts on their South American wintering grounds were they will often flock together with other martin species.
Where to Find a Roost? Migratory Purple Martin roosts are typically associated with larger bodies of water where reed beds and dry islands with low, thick brush provide sanctuary from predators and a micro-climate warmer and less windy than land. In urban and suburban settings, migratory roosts sometimes form in trees or on man-made structures such as bridges and pipes. Winter roosts in South America usually occur in urban settings, often in small parks. Scores of migratory martin roosts are thought to exist in the eastern half of North America, and some can be very large. It was estimated that one roost at Lake Murray, South Carolina contained 703,000 martins. Although this is exceptional, many martin roosts are large enough to be detected by weather radar. Studies indicate that martins using a particular roost may come from a wide geographic area; flying many miles to join other martins. Individual martins may use a roost for several weeks before migrating, but the roost itself may last 8-12 weeks or more until all birds are gone. Once established, martin roost locations may be reused for many consecutive years.
Roost Conservation: Migratory and wintering roosts are critically important to the annual life cycle and ecology of Purple Martins. Roosts can be a spectacular sight with tens of thousands of birds descending at dusk. Visiting a roost is a unique bird watching experience, and roosts can provide community and conservation groups a focal point for environmental education programs, birding festivals, or ecotourism promotions.
How You Can Help: Project Martin Roost is a cooperative research project between the PMCA, its members, and bird enthusiasts everywhere. It is designed to protect and promote Purple Martin roosts in North and South America.
The first step in conserving Purple Martin roosts is documenting their occurrence. Radar images suggest that more than 350 migratory roosts occur in the eastern U.S. and Canada; however most of these locations are undocumented. Where exactly are these roost sites? How many exist in North and South America? Are there any issues with established roost sites? This is where you can help the most!
If you have visited a roost please submit a report. Keep in mind that roosts do occasionally move and knowing whether a roost is still active at the previous or new location is very important. Some roosts have been detected with radar, but it may not be known how many martins are there. Please consider visiting some of these roosts to help improve the roost database. With your help we can help to protect and improve roosting locations for martins throughout the range.