Purple martins arrive in Missouri; Study finds birds fast track home

In the birding world, nearly everyone has a favorite. In Missouri, many people choose the bluebird, the state bird.

But another species, the purple martin, has a devoted following, too. These largest of American swallows arrive in Missouri throughout early spring, with many reports of "scouts" logged online, and Jim Switlick of Nevada has already spotted one, according to a scout report on www.purplemartin.org.

Purple martins are totally dependent on man-made housing and faithfully return to the same locations each year, so it's understandable that human "landlords" anxiously await the return of "their" birds from wintering grounds in South America.

Reports of "scouts" with dates/locations are made almost daily on an online data base maintained by the Purple Martin Conservation Association, a nonprofit conservation organization.

The earliest reported purple martin was in Farmington on March 1. Among other early arrivals: Boonville, March 8, and to Forest Park in St. Louis on March 23.

While purple martins begin returning to Missouri after about March 1, migration is drawn out. Most new arrivals are not seen in the northern half of the state until after about April 1.

Hobbyists marvel at the returns each year and sometimes wonder how a martin can get here so quickly after the first few warm days of spring. New research in which the PMCA participated gives some clues.

Pub-lished recently in the journal Science, a female martin -- fitted with a tiny "geo-locater" --returned in spring from central Brazil to Pennsylvania in just 13 days --astounding professional researchers. Apparently with a warm tail wind, a martin can cover well over 300 miles a day in returning north in spring.

The first wave consists of senior martins -- three or more years old -- followed in a few weeks by two-year-olds. Martins two years or older are called "adults," with adult males sporting full dark-purple color. Females are a bit drab, with a gray breast.

One-year-old martins -- called "sub adults" --arrive 10 to 12 weeks later than the older birds -- in April and May. These younger birds -- males lack full purple dress --are more easily attracted to new housing locations, which they may not choose until early June.

The term "scout" actually is a misnomer. These are simply older experienced birds that are eager to reclaim their housing.

Some arrive dangerously early and may perish when cold temperatures clear the air of flying insects. A historic cold snap in April 2007 killed many martins in Missouri.

For some fortunate martins, many landlords today offer emergency feeding of thawed crickets, live mealworms or even small bits of scrambled eggs flung into the air from a plastic spoon and placed on elevated platforms and in compartments.

A generation ago, many people erected purple martin houses in the belief that these birds consumed mosquitoes, but according to the PMCA martins do not specialize. A martin's diet is diverse and includes many kinds and sizes of insects, from leafhoppers, flies and beetles to dragonflies, bees, wasps and grasshoppers.

Today, most hobbyists host the birds simply for pleasure. As a species, purple martins are relatively common throughout Missouri, with the greatest numbers found in the southern half of the state, according to North American Breeding Bird survey.

Many martins nest in housing in open rural yards and on boat docks, but are happy to reside in urban areas, too. Colonies have been established in Forest Park, St. Louis, and on the grounds of the Monsanto Education Center at the Missouri Botanical Garden.

But there are localized areas of decline, particularly in the state's urban areas where lack of open space and waning tradition may be one cause. The martins in St. Louis city probably number fewer than 100 pairs.

Even in areas where martins are present, many people may try for years to attract them without success, or their colonies disappear. Hobbyists may be unaware that problems such as competition from invasive non-native birds -- European starlings and House Sparrows -- or predation from raccoons or rat snakes caused abandonment.

While generations of Americans have hosted purple martins -- the custom adopted from Native Americans who hung out nesting gourds -- specific techniques to help a colony thrive emerged in the past decade, based on research conducted by the PMCA and landlords in the field.

Among innovations are deeper compartments to protect nestlings from rain and aerial predators such as owls, specially-shaped entrance holes designed to admit martins while excluding starlings -- and unique pole guards to thwart rat snakes and raccoons which are common in Missouri.

Because purple martins are birds of the open sky -- catching insects on the fly -- the PMCA's number one tip: place housing in the most open space available, but where the colony can be enjoyed and monitored.

More information about purple martins can be obtained from the Purple Martin Conservation Association -- which is focused on aiding martins and landlords -- including a products catalog and information booklet, with advice on attracting and managing a colony, and data sheets to participate in "Project MartinWatch" a national effort in which participants monitor nests and mail information to the PMCA at season's end.

To obtain the booklet, contact the PMCA at 814-833-7656 or online at purplemartin.org.