All during this long snowy winter, I loved watching the birds outside my kitchen window, often frantically searching for food but always so beautiful against the stark white of the snow. As I watched the snowbirds, finches, and occasional woodpecker, my eyes often looked upward to the two birdhouses swaying in the cold winter wind. These birdhouses are special to my husband and me because they will, with the arrival of spring, house our most favorite of birds, the purple martin.

There is a long tradition, in both my husband's and my family, of acting as "landlords" of these apartment-style birdhouses for purple martins. Both our grandfathers had them in their yards. My grandfather even had a special calendar where he marked the arrival and departure of these special winged friends. I never dreamed that one day I would also mark my calendar with the comings and goings of these wonderful birds.

It took awhile for us to get purple martins to come to our house, but early one May day they arrived and since then they come back each year. Our colony grows every year, which is a delight to us. Not only are they wonderful songbirds, but they are famous for their aerial acrobatics, as well.

Purple martins feed almost entirely on flying insects and do this very efficiently. They are known as diurnal aerial insectivores; simply put this means they feed on insects while flying in the daytime. It is a wonderful sight to watch purple martins do their aerial acrobats in order to catch flying insects.

There is an old wives' tale that if you have purple martins you will not have mosquitoes. It is true that they eat mosquitoes, but their diets also consist of dragonflies, ants, bees, beetles, moths and numerous other winged insects. Purple martins eat while in flight and very rarely ever land on the ground, unless to pick up nesting materials.

Purple martins, the largest members of the swallow family, are beautiful steely blue/black songbirds that spend their winters in the Amazon River basin and farther south in Brazil. They migrate to these locations to feed on available insects, but they travel north to nest and breed in many locales across the United States including Pennsylvania.

Unfortunately, much of their natural breeding area has been taken over by non-native competitors like sparrows and starlings. As a result, these birds are completely dependent on humans to supply them with nest boxes in order to breed.

One would think if purple martins are so dependent on us, they would be content with any old available birdhouse, but that is not the case. The house should be white; metal is best, positioned 10-15 feet off the ground with a 2_inch diameter entrance opening, give or take 1/4", and located 100 feet from a human dwelling and 40 feet from trees. The house should come with door plugs to close compartment holes during the off season and in early spring. This is essential for keeping sparrows and starlings from talking over purple martin housing. Purple martins will not use a nest box if another bird starts to nest in it. Each year, the nests must be thoroughly cleaned and secured with the door plugs.

Their breeding season is approximately a 70 day cycle. During this time they are busy building a nest, laying their eggs, raising their young and bringing happiness to their devoted "landlords." After the young have fledged, the purple martins begin to leave the colony area to start assembling into larger flocks.

Usually two weeks before their departure, there is increased activity near the nesting houses. We can always tell when it is getting time for them to depart. They spend daylight hours perching on high wires, preening and foraging for food. The direction they leave is not always south. Sometimes they first head north to meet up with other colonies of purple martins before heading south. Their trip south is long and hard, but most necessary for them to have enough insects for the winter months.

Purple martins can bring many, many hours of enjoyment while they are in your backyard, but their continued presence in Pennsylvania depends on committed and informed "landlords" who are willing to devote the time necessary to managing their sites.

Once you have established your houses according to the purple martins' specifications and they approve of you as "landlord," they will return faithfully to your backyard year after year. In return for your investment, you will get to enjoy their wonderful aerial acrobats and beautiful songs.