As all gardeners know, working in the garden is not just about plants. Being outside with your hands in the soil makes you keenly aware of animal life, too. Over the years, I’ve gardened in tandem with a majestic blue heron, a band of three crows and a playful red fox. Now, with the arrival of warmer weather, I’m looking forward to the return of the purple martins.
Aside from being able to identify their houses (virtual mansions of the ornithological kind), I didn’t know much about these birds until recently, when my garden club hosted two members of a local purple martin society. Ever since, I’ve been scanning the skies for the colorful species. According to the experts, the first wave of birds will be arriving in my area soon.
Purple martin house
PURPLE MARTINS HEAD NORTH IN THEIR ‘WINTER’
Of the eight swallow species, purple martins are the largest. The dark, bluish-black birds arrive in North America each spring, soaring on the jet stream from their native southern Brazil. It takes them about five weeks to fly the 10,000 miles, which is quite a feat for a bird that weighs only about 2 ½ ounces.
Female purple martin in flight
Like many neotropical birds, purple martins travel north in order to breed. The birds arrive at the height of the insect season, establishing themselves in colonies located close to water where there is the greatest food supply. In total, the migration can take up to 2 to 3 months to complete.
ONLY MAN-MADE HOUSING WILL DO
In Brazil, purple martins are considered a public nuisance, mainly due to their large numbers and preference for roosting in trees around central plazas. As a result, some municipalities have gone so far as to install sirens and other devices to chase the birds away.
In the United States, on the other hand, it’s a different story. Here, large groups of purple martins return each year to establish neighborhoods in man-made housing only. In fact, they are the only bird species that is totally dependent on human-supplied housing. Not only do they like people, but they actually prefer living in close proximity.
As a species, purple martins favor locations in wide-open terrain, usually in the form of pole-mounted martin houses or gourds. This keeps them out of reach of predators like owls and hawks that dwell in tree cavities. They’ll generally avoid congested suburban areas and instead roost in open meadows or fields located near lakes or other bodies of water.
Although just one male and female live together in a room or gourd, the highly sociable birds house together in colonies, where they interact as a unit, sharing food and singing to each other. All told, a group of houses or gourds can host as many as 60 to 70 birds over a 2-month period.
Purple martin pair
THEY SEND SCOUTS
Now is the time of year when the first scouts (who are the oldest birds) begin arriving from Brazil to check out their nesting sites from the previous year. The scouts pave the way for the rest of the flock, which arrives 4 to 6 weeks later. Built like a glider, the birds can travel at speeds of more than 40 miles per hour.
THEY ONLY FEED ON THE FLY
And purple martins bring a whole new meaning to eating ‘on the fly.’ According to Mike Dickson of the Purple Martin Society of Frederick, Maryland, they only recognize food that is in flight, meaning that they primarily snatch insects in midair. Adept in performing complex aerial acrobatics, the birds even drink in the air. They accomplish this by flying low over lakes or ponds while scooping up water with their bills.
A female in flight
Indeed, you’ll never find purple martins foraging for food on the ground, or eating seed from a feeder. People who choose to feed the friendly birds will discover they’re quite open to the idea, but only if the food is flung to them. On occasion, human intervention is necessary when periods of cold or rain suppress insect populations. This can spell death to entire colonies.
THEY SING REALLY WELL
One of only a few colony birds that love to sing, purple martins’ throaty chirps can be heard May through June during the breeding season. According to the Cornell Lab of Ornithology, males make a croaking song during courtship that can last up to 4 seconds. People say that once you’ve heard it, you’ll never forget it.
Males perform the dawn song
Purple martins sing in a combination of gurgles, clicks and song, with the loudest singing occurring before daylight. Males perform this dawn song possibly to attract other birds to the nesting site. Click here to hear a few of their beautiful songs.
AN EARLY DEPARTURE
All too soon, by the end of July or first week in August, the birds prepare to leave for their migratory roost. Many purple martin lovers describe this time as a sad one, when they awake to find the birds gone and their houses empty. It’s as if suddenly, the countryside has fallen silent.
Female purple martin
Once airborne, the birds fly south to a designated spot to roost before heading back to Brazil. Often they gather by the tens of thousands. In fact, the largest roosting colony on record was estimated to have 700,000 birds at one time. All told, there can be thousands of purple martins in the sky at one time, so many that they often show up on Doppler radar as giant rings.
Interested in attracting purple martins? Here’s a great article from the Purple Martin Conservation Association in Edinboro, PA, a non-profit conservation organization.