A Lesson
Re-Learned:
Missed Opportunity at Crooked Creek Lake
Ken Kostka
Purple Martin Preservation Alliance
Pittsburgh, PA
www.purple-martin.org
12/11/09
I
cannot emphasize how critically important it is to prevent ALL other species of
birds from using your martin housing when you are attempting to
attract that first breeding pair of Purple Martins. You must diligently and
relentlessly prevent ALL other species from nest-building, even the "nice,”
native birds like Eastern Bluebirds and Tree Swallows. They are just as good as
starlings and House Sparrows at chasing away martins! Discouraging other species
is necessary because when a pair of birds builds a nest,
they develop what is called “site tenacity,” which causes them to defend the
nest and the area around it. In the case of a martin house, non-colonial
species tend to
claim and defend the entire house, not just the cavity they are using;
they will
aggressively repulse (harass and chase away) other birds that try to use the
house. A pair of inexperienced cavity-hunting martins will usually be repulsed by species that have already claimed the house,
because the martins have not yet developed enough of an interest in the
house to stand their ground.
It was a lack of diligence in keeping non-martin species from using the house
that may have cost me the opportunity to establish a new colony site in 2009.
I’ve tried to attract martins to Crooked Creek State Park in Ford City, PA
since 1999. These efforts have included erecting two T-14’s with large gourds,
playing the dawnsong, and deploying decoys, among other social attraction
techniques. Though it’s a 25 mile drive to the lake, I make it a point to visit
at least weekly in May and June to keep the housing free of all other species.
(I do not open the housing until May 1st). In mid-June of 2009, the
ranger at the park, Mike Mazzocco, called to report that a martin had been seen
on one of the houses. This was not highly unusual since subadult male martins
had been spotted on several occasions in the past several years. So I skipped my
weekly visit because I was extremely busy that week. When I did visit two weeks
later, I found three separate nests in three adjacent gourds – a Tree Swallow
nest with eggs, an Eastern Bluebird nest with eggs, and an abandoned Purple
Martin nest with dried green leaves. I strongly suspect that the martins
abandoned the housing because of harassment from the nesting Tree Swallows and
Eastern Bluebirds. Had I made my normal weekly visit, I would have been able to
keep these other species from using the housing. Had this pair of martins nested
successfully, I might have established only the second Purple Martin colony in
all of Armstrong Co., PA. Ten years of effort may have been undone by two weeks
of inattentiveness. This incident
underscores the need for VIGILANCE, the PMPA’s
mantra - vigilance against predators, nest site competitors, nest parasites,
and poor weather!