Purple Martins are the largest member of the swallow family in North America. They are about 8” in length with a wingspan of 18”.
The male is uniformly dark, glossy blue-black. The female and juveniles are light-bellied. Mature coloration is not achieved until after the first breeding season.
Range and habitat
Purple Martins migrate from South America to nest in North America ranging from northern Mexico into southern Canada. Their habitat is open to semi-open country, towns, and farms, often near water. In eastern North America Purple Martins nest where there are humans as they have become mainly dependant upon people to provide nesting sites.
Purple Martins are aerial insectivores meaning they feed entirely on insects which they capture while in flight. They tend to forage high above the canopy or swoop low over water. Their numbers decline in areas where development and cultivation significantly reduce the insect population. Likewise, conditions such as drought, brushfires and sudden drop in temperature can reduce foodsource.
Martins winter in South America, primarily Brazil, where they congregate in large flocks probably for protection. Their migration is staggered, with the first arrivals appearing as early as January in the southern US and the last arriving in Canada in May. Adult males, referred to as “scouts” are usually the first Martins seen at a nesting site, followed by adult females and finally, the second-year birds – those that hatched the previous season. When the breeding season is over, migration back to South America is staggered as well, with the first birds leaving in July and others staying as late as October
The majority of Purple Martins nest in the houses and gourds which have been provided for them. Some return to previous nesting sites, many to the same general region. Males usually arrive first to claim their territory and attract a female. Once a pair is established and a nesting site is claimed, both male and female may gather nesting materials and prepare the nest.
The female typically lays 4 to 6 pure white eggs although smaller and larger clutches have been noted. One egg is laid each day. The female begins incubating the eggs the day before the last egg is laid. The eggs hatch after approximately 16 days of incubation. The young are altricial, without feathers and with their eyes closed. They are fed by both parents and are ready to fledge at 26 to 35 days.
Within a few days after the last young bird has fledged, both adults and young will stop using the martin house. Some Purple Martins may briefly visit the house in the late season for short periods. In Southwest Florida, martins will gather in large flocks in a communal roost in stands of trees near the Gulf of Mexico between late July and early September prior to migrating back to South America for the winter.