Thursday, June 6, 2013

Knox Preserve Welcomes Purple Martins

In the Fall of 2012, the Stonington Town Committee of Avalonia Land Conservancy gratefully accepted a Grant from the National Audubon Society for the purpose of establishing a Purple Martin population on the Knox Preserve.
Purple Martin seeks gourd with northern exposure, can you help?

Martins are one of several species of birds that are aerial insectivores, meaning they eat insects while on the wing. They prefer open spaces for hunting, and insect levels are often higher over naturalized fields, especially those with a water source nearby. The restored fields, small pond and location near the shore make the Knox preserve a perfect site. Martins are cavity nesters and originally used abandoned woodpecker holes. However, from as early in historical records as pre-1800 it has been reported that Native Americans in the Southeast provided hollow gourds, set in colonies, to entice the Martins. They have become not only dependent on humans for their home sites, but are also very tolerant of human activity near and even within the nests. Due to loss of housing, loss of habitat, and pesticide use decreasing insects over cultivated fields and lawns, Martin populations are plummeting and they are now considered threatened in CT.

With our Audubon grant we purchased a 12 unit Super Gourd -Housing system with pulleys and locking winches to make our Landlord jobs easier. With help from a team of CONN College Students from the Goodwin -Niering Center for the Environment, we did our research and set up the system on April 27. The very next day Purple Martin scouts, the earliest arrivals, were on the location and checking out the new real estate.

Being a Martin colony landlord is a big responsibility. The houses have to be prepared with beds of pine needles to entice the nesting pairs. We do nearly daily checks to observe behavior and signs of nesting. They have been taking forever this spring to make their decisions about gourd choice! We also have to be vigilant about nest site competitors and even predators. House Sparrows frequently invade and take over Martin cavities, and they have even killed nesting birds to evict them. As landlords we need to be on the watch for this and have the instructions to remove nesting House Sparrows (which are not covered by Federal Protections as they are non -native and invasive). Another strategy is to provide alternate nesting sites. Visitors to Knox will notice 12 new Bluebird nest boxes. As of now we have no nesting bluebirds, but we do have several pairs of Tree Swallows (which is great), one box with a House Wren investigating and a few boxes where House Sparrows have taken over.
Tree Swallow headed home

In the next weeks we expect nesting behavior to intensify as the pairs get busy enhancing the nest material inside the gourds. We will regularly take down the colony (that’s the reason for the winch system) and, when lowered, we can inspect each nest for eggs. Throughout the season we can check for hatching success, chick count, fledging dates, and when needed, even do nest material change outs to decrease infestation by mites. If we have successful nests, we can also do Federal Bird Banding on our young which will further assist with studies of the species. The Martins not only tolerate this intrusion, they seem to welcome it and thrive!

We will keep you posted on our nest checks and observations as the season goes on. You can stop by and observe the colony from a distance, so bring your binoculars. At this time of year we ask visitors to stay out of the fields to avoid disturbance to all nesting birds. The Purple Martins put on quite a display with their flight and twittering chatter. Enjoy them.

Written by Beth Sullivan.
Photos by Beth Sullivan (top) and Rick Newton (bottom).

To find out more about Purple Martins visit the Cornell Lab of Ornithology web site.

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