For many decades and even for generations of farm owners, having a colony of purple martin birds in the yard during the late spring and summer was a common experience on a great number of farms in Wisconsin and elsewhere.
In most cases, the birds were self-sufficient except for having the farmers clean out the nests after the birds departed.
But that's no longer true because of a significant decline in the population of the bird species whose major habitat is in the eastern half of the United States and travels to South America during the winter here.
In Wisconsin, the purple martin population has declined by about 75 percent from its high point, according to Tom Rank of rural Sheboygan Falls, who is the president of the Eastern Wisconsin Purple Martin Association, which was formed in February of this year.
Rank told Wisconsin State Farmer that competition from starlings and sparrows during the nesting season and bad weather - a combination of low temperatures and rain or snow lasting for at least two and up to five days - are largely responsible for the demise of the purple martin population.
He said it is not due to the use of insecticides on farmland or other properties.
Although based in Sheboygan County, the group membership (no fee at the moment) is open to anyone interested in preserving and restoring the purple martin population.
At the group's monthly meetings on the 3rd Thursday of the month (6:30 p.m. at the Intergenerational Center, 1500 Douglas Drive at the northeast edge of Plymouth off County E), updates and education about housing and caring for purple martins are the major topics.
Record early dates
As with other bird species, insects, and plant growth, some record early dates for purple martin arrivals were reported by scouts around Wisconsin this spring.
By April 19, the www.purplemartin.org/scoutreport Web site indicated that observers had seen 63 adult birds in the state already this spring - the earliest being on March 27.
Rank reported that the first male appeared at his residence between Sheboygan Falls and Oostburg on March 29.
He pointed out that the birds migrate northward in several waves with the birds with those raised in the previous year being the last to do so.
The national website, which tracks the migration, indicated that a few birds had already reached Canada this spring while the young birds were still in the southern United States.
Merely putting up housing in the form of wood, plastic, or metal compartments or gourds to invite purple martins to take up residence on one's property is no guarantee of immediate success because of the limited number of birds and because one must wait for the birds to find the site and be comfortable with it, Rank explained.
In the Eastern Wisconsin association's latest newsletter, a couple in northeast Sheboygan County reported that in the first two years after they put up houses they did not see any birds but some birds appeared for a few nights last year - though not to stay and nest.
Among the fundamentals recommended by the national Purple Martin Conservation Association (PMCA) are to put the housing units on top of a 12- to 20-foot pole located at least 60 feet away from any large trees (a hiding place for predators) and a minimum of 30 feet to an ideal of 120 feet from human housing.
On April 14, members of the Eastern Wisconsin association put up a T-14 house, including a decoy bird, at the edge of the parking lot at the Intergenerational Center here.
To attract purple martins today, high-tech artificial lures are in fashion, Rank points out. In addition to the decoy, the association's house is set up for playing the Dawnsong CD (a mimic of the bird's sound) intermittently from dawn to dusk.
Also known as sound magnets (www.songbirdmagnet.com), similar to mimic calls for duck and turkey hunting, those units cost $35 to $50 and should be covered with plastic to protect them from rain.
Another high-tech attractant is the power horn - a CD player available for as little as $7.
Rank describes the Downsong CD as a form of advertising - a mimicking of a male purple martin's call to young females for mating before the annual southerly migration begins. Those calls, if made from heights of 500 feet in the early a.m., can carry for miles, he indicated.
Purple martins are a communal bird, which means that they prefer to nest as a colony group (unlike other birds which prefer isolation and control over a certain amount of territory).
Therefore, the various supplemental techniques to draw them to a particular site are necessary and appropriate, Rank and Eastern Wisconsin Association vice-president Greg Zimmermann remarked.
Artificial stimuli, such as the mechanical vocalizations create an illusion that a certain place is an active populated site, can be augmented with nesting area mirrors attached with duct tape so birds will see reflections of themselves, Rank observed.
Attracting the first pair is the key to establishing a colony on one's property, he said.
Since purple martins are not considered to be clean birds, do not expect to attract them with shiny paint housing, Rank remarked.
Instead, use an old paint brush to smear mud on the outside of the housing unit near the entrance and, if necessary, provide some mud that they might use to build a mud dam inside the house, he advised.
Once purple martins are attracted to a site, it is crucial to offer them protection from predators and to offer them supplemental food when weather conditions limit their flying and that of their favorite natural forage such as dragonflies, butterflies, and bees (but not mosquitoes) for several days, Rank observes.
He and Zimmermann also recommend placing two decoys, resembling black adult purple martin males, made of wood or plastic that will fool and perhaps deter future attacks by predators such as Cooper's hawks.
At many sites, having an entrance hole that does not allow starlings to enter the housing unit would be important for the purple martin survival and reproduction. Information on how to cut and size such an entrance hole is readily available from the PMCA.
An ideal size for housing compartments is 7 by 12 inches and the diameter of gourds provided for housing should be 10 to 12 inches.
At the April meeting here, association director Ike Kumrow demonstrated how to drill a one-inch hole in gourds in order to provide extra venting for the nestlings.
After the hole is cut, Kumrow advised threading in a PVC elbow joint readily available in farm supply or hardware stores in order to prevent rainwater from entering the nest.
An option would be to put a screen on the end of the vent, turned downward, to stop pests such as yellow jacket bees from entering but it was noted that the screen might could plug up with dust being stirred from the nest.
Rank explained that moisture can easily build up in gourd housing when the nestlings are about 20 to 21 days old.
With the additional trapping of heat, this could create sauna-like conditions and be fatal for the young birds, he pointed out. He also noted that tree swallows love gourd housing and will compete with purple martins for the space.
For gourd houses, gourds with chimney shapes are preferred. Rank noted that the birds like the horizontal gourds but warned that this shape is more likely to lead to moisture problems in the nest.
At any time during the birds' presence, supplemental feeding is appropriate and necessary, Rank stated. A video depicting the "flipping" method used by a man in New Jersey was shown during the meeting here.
The highlight of that video was the tossing or even slingshotting of crickets that can be ordered on-line, frozen, and then thawed before being made available to the purple martins.
The video presenter indicated that the birds need to be trained to pursue and catch the airborne crickets but that once a few of them do so the remainder will follow their lead.
Mealworms are another and less expensive type of supplemental food, along with scrambled eggs - both of which would be served in a platform feeder around the bird house.
The New Jersey man was pleased that only about two dozen of his colony of about 60 purple martins perished when a series of hurricanes moved through the area.
Rank commented that the "flipping" method has not worked for him and that feeding scrambled eggs should be a last resort.
He said not all purple martins seem willing to accept supplemental food and suggested that eggs are too high in fat, leading to possible diarrhea among the birds.
Instead of waiting out periods during which the weather is stressful on the birds, provide supplemental feed "before you have to," Rank advised.
At all times, provide the birds with egg and oyster shells, other types of grit, mud, and bedding materials (during the nesting period), he added.
Egg shells could often be obtained from an area restaurant but they should be rinsed and microwaved in order to guard against salmonella, he cautioned.
Rank can be reached by phone at 920-564-6507 or by e-mail to email@example.com.
The association has also developed a Web site at http://www.localendar.com/public/EWPMA.
Rank does not know of any similar local or regional purple martin organization in Wisconsin.