By MITCHELLE STEPHENSON, For The Capital
Published 05/14/09
Dave Gillum is the kind of volunteer that any organization dreams of recruiting. About two years ago, Dave thought he might enjoy learning a little more about birding, or bird watching.
He started with an interest in the hobby and is now heading up a group that oversees 50 bluebird-nesting sites at the Smithsonian Environmental Research Center in Edgewater.
In all this year, they're hoping to see their efforts pay off with close to 200 eastern bluebird fledglings.
Dave is not a naturalist by training. In fact, he is a computer mapper for a county agency. He and his wife live in Riva. About two years ago, he thought he was spending "too much time indoors," and decided to do something about it.
He started volunteering at the Patuxent Wildlife Reserve in Laurel and he took a part-time job as a sales clerk at the local Wild Birds Unlimited store in Gambrills. He thought working at the bird store would help him learn a little about birding.
"In that year, I learned a lot," Dave said of his experience at the bird store.
He was also volunteering to check bird boxes at Patuxent. Then he learned about SERC, and since it was much closer to his home, decided to call Karen McDonald to see if they needed any help.
SERC had just lost the volunteer who maintained the trail and the 40 or so bird boxes, so she was excited to have Dave as a potential volunteer.
Eastern bluebirds over-winter here in Maryland, and in the spring they begin nesting. The pretty blue birds have many predators, including snakes and raccoons, but one of the biggest threats to the bird is that, as a cavity nester, their habitat is being threatened by development. People simply don't keep dead trees on their property, which gives the birds a place to build their nests.
Dave said that as soon as the weather begins to get warm, bluebirds begin building their nests, so spring is his busy time.
"They make a nice, neat nest," Dave said. "It's made out of woven grass."
Once the nest is made, the female begins to lay one egg each day until she has a clutch of three to five eggs. She then sits on them for about two weeks until they hatch.
She feeds the hatchlings worms and other insects for another two weeks until they leave the nest. Then Dave cleans out the nest and another bird will come in and do the same thing.
One of the nests we found on a recent Friday afternoon already had four bright blue eggs in it. Dave tapped the side of the nest to let the bird know that he was there. She flew out and he lifted the latch on the box. He was able to swing the top of the triangle-shaped box forward, easily exposing the indentation of the nest and the eggs.
Part of Dave's job is to check the nests, and clean them out once the fledglings have left. Dave said that they don't leave the nests there because they can contain mites and parasites. Plus each bird likes to build her own nest.
Each box will get used two to three times during the year. Dave also looks out for predators.
"Snakes like to eat the eggs, as do raccoons," Dave said.
They hang 3 inch PVC up the length of the pole as a baffle to prevent those predators from getting in.
Another threat is the house wren, which will also attack the nests, busting the eggs, but not eating them.
Invasive species are also a problem, but they cut the hole in the box to just one-and-a-half inches to prevent some of the larger birds from getting in and attacking the bluebirds.
In his first year in charge of the eastern bluebird boxes on the SERC property, Dave saw 170 fledglings leave the nest. He is hoping for 200 this year.
As of early May, he's already seen about a dozen hatched chicks.
Dave has two helpers, Bob Newburn and Richard Mills, who also take a part of the trail, so that each person only has to check on a third of the boxes several times a week.
They're expanding now, and have a house for purple martins, plus boxes for wood ducks.
In addition, they're looking at boxes for screech owls and kestrels.
"The goal is to help cavity nesters." Dave said. "Birds that traditionally nest in a woodpecker cavity. We don't maintain old dead trees with holes in them, so we put up the boxes to help the birds."
Dave described different kinds of nests: "a bluebird nest is a nice woven nest made of grass; a chickadee builds its nest out of moss; a house sparrow builds a crazy nest - they'll use plastic, string, whatever they can find - and wrens use big sticks."
Finally, Dave said that the best way to get bluebirds to nest near your home is to start by building a bluebird box, then lure them with mealworms from the pet store.
"If you look up bird boxes on the Internet you can get easy plans for building the Peterson or NABS style box," Dave said. In addition, you can get more information by visiting the Maryland Bluebird Society at http://www.mdbluebirdsociety.org/.
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