By Bernheim
Everything was ready. All the rooms were freshly cleaned. New, unused materials carefully put in place. The weather was perfect. On April 3 the first of our visitors arrived. What joy to welcome them back! Then it got cold. In just a couple days all of our guests had disappeared. I grew concerned. Would they be okay? April 10 saw the arrival of more visitors. By the 14 they had all left again. I started to despair. Had I done something wrong? So begins the roller coaster ride of emotions that is the Purple Martin breeding season.
I was not alone. Across the eastern half of the United States, expectant landlords were anxiously awaiting the arrival of their birds as well. I need not have worried. This coming and going is actually normal behavior. Purple Martins don’t use calendars and by the 28th of April, our birds were here in force. I say “our birds” because studies have shown that Purple Martins are site loyal. They will return every year to nest in the same place they did before. Even first year Martins will return to an area within 10 square miles of where they were born!
East of the Mississippi River these beautiful birds are nearly 100% dependent on humans for nesting sites. At Bernheim Forest we maintain two separate colony sites. As a volunteer, it is my privilege to monitor these nests throughout the season.
The first colony is located at the bottom of the hill in front of the Education Center. This is a well established colony and it fills up fast. Of the 30 spaces available, only 4 were left unused this year (last year we had 8 spaces unused). While I worried about the weather, the Purple Martins went about the business of nesting. On May 5, the first egg of the season was laid. Many more quickly followed. Purple Martins lay between 1 and 8 eggs with the average brood being 5 eggs. By June 1, this site had 39 little ones hatched out with an amazing 84 more eggs to go!
The Edible Garden plays host to our other colony. This location was just started last year. It can take a few years to get a colony fully established. Although only in its second year, by June 1 this site was home to 5 young hatchlings with another 40 eggs waiting to hatch. This amounted to a 50 % increase over last year at this site! I’m optimistic about the future of this new colony. Stay tuned.
After hatching, the parents will feed each baby bird up to 60 times a day. That is a lot of bugs! The nestlings grow quickly. In only 28 days, these young birds will be fully fledged (feathered) and ready to fly. It’s a bittersweet time. Like watching your kids move out. You have to let them go. When a young Martin leaves the nest for the first time the whole colony is there to help. The adults will swarm the youngster and offer support. If they falter in their flight the adults will fly underneath and bump the fledgling back up until they can safely land in a tree or back at the nest! It is an inspirational sight to see.
Of course, it also means the time to leave is fast approaching. By August our colonies have grown quiet and still. Purple Martins spend most of the year in the rainforest of Brazil. They only visit us long enough to raise their young. Once all the young have fledged, Purple Martins will start to gather in huge flocks, called roosts. The birds in these roosts can number in the millions. Then they all migrate to South America.
This year at Bernheim, we had 36 nesting pairs of Purple Martins. They managed to successfully raise and fledge over 160 young birds. I miss the chatter and all the hustle and bustle of an active colony. It just seems so empty. But, I know they will return in the spring, and I can start the cycle of worry and joy all over again.
–Jim Scout, Volunteer Naturalist