How to Attract Purple Martins
Purple Martins are the only
bird species in the eastern half of North America entirely dependent upon
human-supplied nesting cavities for reproduction. It can be a
challenge to establish a Purple Martin colony, so be patient. The
suggestions below will help you succeed.
Learn everything you can about Purple Martins. Talk with other
martin landlords and visit the web site (www.purplemartin.org) of the Purple
Martin Conservation Association, an international nonprofit organization
dedicated to aiding Purple Martins through landlord education and scientific
Choose the Right Location (see diagram)
Martins have very specific space requirements. One of the main
reasons people fail to attract purple martins is that they place their martin
housing incorrectly. Martin housing should be in the center of the
largest open spot available, about 30-120 feet from human housing.
Place the housing where you can see it so you can enjoy watching and hearing
the martins. There should be no trees within 40 feet, preferably 60
feet., of the housing. In the southern half of their breeding range,
martins are less fussy about house placement, so sometimes housing can be
within 25 feet of trees and still attract martins. But the farther
housing is places from trees, the better. Housing height should be in the
range of 10-17 feet. Don't attach wires to the house or pole,
especially if they lead to trees, buildings, or the ground. Predators
can use the wires to access the housing.
Put up Manageable Housing
Your chances for success will be better if your housing is easy to
manage. Choose a pole that telescopes, or is equipped with a winch or
rope & pulley, and housing that has easy access to the compartments.
Houses and gourds should be white, or a light color. White housing
attracts martins best and reflects sunlight, keeping nestlings cooler.
Cavity floor dimensions should be at least 6"x6" but larger cavities
(7"x12") are preferred by the martins, and offer better protection from
predators and rain. Unfortunately, larger compartments are also
attractive to European Starlings, but a modification to the entrance hole
will minimize starling problems. A round entrance hole of 2-1/8" is
preferred by purple martins, but they will use a range from 1-3/4 to 2-3/8."
Make sure there is adequate ventilation and drainage in each nest cavity.
Many houses can be improved if need be. Add insulation to the attic,
remodel interiors to offer double-size compartments, and add porch dividers
to houses with shared porches. Dividers help keep males from claiming
extra compartments, and can double occupancy rates. They also keep
nestlings from wandering to other compartments where they can get lost and
die, or steal food from younger nestlings, causing them to starve.
Open Housing at the Right Time
Adult martins are rarely attracted to new breeding sites - they return to
the sites where they bred previously. Typically, it is sub-adult
martins (last year's young) that colonize new sites, and they begin arriving
about 4 weeks after the first adults in the northern third of the martin's
breeding range, 6 weeks after the adults in the middle of the range, and 8
weeks after the adults in the southern third. At uncolonized sites
then, opening housing when the "scouts" are due decreases chances of
attracting martins by giving House Sparrows and starlings 4-8 weeks to claim
the site before the sub-adult martins arrive. To improve your chances,
keep housing closed until it's time for sub-adults to arrive (see
migration-timing map for adults, and add 4,6, or 8 weeks onto the dates
shown, depending on latitude, to determine sub-adult arrival). At
active sites, the first martins usually show up within a week or two of
previous years' arrival dates. The strategy at active colony sites is
to have your housing ready, but keep it closed until some martins return.
Martin migration is a drawn-out affair, with birds arriving for 8-12 weeks
in the north, 16-20 weeks in the south. Martins can arrive and begin
nesting up through the end of June, range-wide, so keep your housing ready;
don't close it up, or let other birds use it.
Increase Your Chances
A few things can be done to make your site more attractive to Purple
Martins. Offer a combination of houses and gourds. Play a
dawnsong recording. Add a Purple Martin decoy or two. Place 1-2"
of nesting material in the bottom of each compartment.
it Too Soon.
Don't close the entrances, or take the housing down, until
late August, as fledglings will be searching for next year's breeding sites
in late summer.
Read More: Managing Purple Martins
For information on the Purple Martin Conservation
Association and receiving their quarterly Purple Martin Update magazine,
visit their web site, phone, or write.
Purple Martin Conservation
Edinboro University of Pennsylvania
Edinboro, PA 16444 USA