The third is through the Florida Keys for martins that populate the east coast into Canada. The Louisianna flyway is used by martins which traverse the open waters of the Gulf of Mexico and nest throughout the central part of the U.S. The Baja Peninsula is used by martins which breed west of the Rockies. Purple Martins winter in Brazil returning to the United States in early spring using three different flyways. Except for a few areas of the Rocky Mountains they are found throughout most of North America. The back is a dull purple with black wings and tail They are typically eight inches long and have a wing span of twelve inches. Females and sub-adults have a gray chest with whitish belly. But the odds are favorable that if you erect a martin house following some simple guidelines and management practices you’ll attract a nesting colony.Īdult male Purple Martin males are a shiny dark purple with blackish wings and tail. Loss of habitat and these two invasive bird species has reduced the Purple Martin population to 10% of that in the 1800s. To this day House Sparrows and Starlings are the number one threat to nesting martins in poorly managed Purple Martin houses. These non-native birds aggressively competed for nesting structures provided by humans often driving off colonies of martins, even killing some. With the introduction of two cavity nesting species, the English (house) Sparrow and European Starling in the mid 1800s, Purple Martins faced a new threat. There is some concern that if humans were to stop supplying nesting structures for these birds they may likely disappear as a breeding bird in eastern North America. Martins have been managed by humans longer than any other North American bird species. They have become the only bird entirely dependent on humans to provide nesting structures.
Today there are no Purple Martins east of the Rocky Mountains observed nesting in natural cavities. From there it wasn’t long before the eastern population of Purple Martins nested exclusively in housing provided by humans, and the behavioral shift was complete. These colonists soon introduced ceramic gourds and eventually wooden houses. As the Europeans entered the New World they adopted the custom from Native Americans of hanging gourds to attract Purple Martins. It may have been for some or all of these reasons that other native tribes began the cultural tradition of hanging gourds to attract Purple Martins and eventually over time martins began to select gourds as nesting sites over natural cavities. There is also some evidence these earliest Americans may have used dead Purple Martins as a natural repellent to protect their furs from insects during summer storage. And much like today, the martin’s pleasant song and aerial behavior is a source of wonder and entertainment. They may have assisted in arousing the camp in the early morning with their singing. Purple Martins may also have acted as a seasonal calendar for Native Americans with their cyclic arrival, nest building, egg laying, fledging of young and departure. This mutual benefit that developed over time between Purple Martins and humans exists to this day. Documents from the 18th and 19th century indicate nesting martins attracted to these early American villages became excited and warned of approaching strangers, drove crows and blackbirds away from patches of corn, and vultures away from meats and hides hung out to cure. At the same time Indians may have discovered the benefits of Purple Martins nesting in close proximity to their encampments. It would have been adaptive for those young martins that fledged these nesting structures to seek out gourds the following year as breeding adult birds. The gourds provided martins a larger chamber than the natural cavities that were available so they were able to lay more eggs and successfully rear more young. When martins began nesting near humans they encountered fewer predators.
We can only speculate how this transition began, but over hundreds if not thousands of years we know that Purple Martins gradually gave up their ancestral ways in a process now known as a “behavioral tradition shift.” They soon discovered martins could be attracted to nest in gourds that were hung with holes in them through out their campsites. Perhaps the earliest Native Americans found martins nesting in a hollowed out gourd that was used as a utensil. How did the ancestral nesting habits of Purple Martins change? It may have been by sheer accident.
In modern times however martins have adapted to nesting in housing provided by humans from multi-room boxes know as “martin houses” to hanging natural or artificial gourds. These birds nested in abandoned woodpecker chambers, rotted out cavities in stands of dead trees, or naturally occurring holes in cliffs and steep banks. At one time the nesting habits of Purple Martins was dramatically different than today.
0 kommentar(er)
