Many of our birds are cavity nesters, that is, they nest in holes in trees and fence posts. Woodpeckers can use their strong bills to chisel holes to create their own cavities. Many other birds, such as bluebirds, chickadees and house wrens must find abandoned cavities in which to nest.
We are too quick to clear timber, especially dead trees, to give woodlots and yard edges a more “pristine look”. As trees are cleared, so are the potential cavities for birds. As a result, birds have a much tougher time finding adequate natural cavities.
An even greater threat to our cavity-nesting native birds has been house sparrows and European starlings. These are non-native birds that were introduced from Europe. They are also cavity nesters. These aggressive birds have displaced many of our native birds from the fewer cavities that remain.
One way to solve the housing shortage for our cavity nesting birds is to provide artificial cavities, also known as bird houses or nesting boxes. More than 50 species of birds – including bluebirds, tree swallows, great crested flycatchers, chickadees, nuthatches, wrens, kestrels, screech owls, wood duck and woodpeckers – will use nest boxes.
Providing bird houses has enabled many species, including bluebirds, to make dramatic comebacks in our area in recent years. Bird houses on your property provide cavities in which birds nest, and also provides some enjoyable bird watching for you!
Bluebirds are already checking out nesting boxes in area towns. They are one of the earlier nesters, often starting their first brood in March or early April. The bright blue male is always a breathtaking sight as he, along with the female, will be going house to house, inspecting for possible occupancy.
Soon, they will establish a nesting territory around their chosen home and nest building will begin. The female will construct the nest in about five days with little help from the male. The female will also do all the incubation once their four to five eggs are laid – the male has no brood patch. But studies have shown that the male may sometimes “spend the night” in the cavity with the female.
The female will incubate the eggs for a little more than two weeks. She will leave the nest only a few times a day to find food. Once the eggs are hatched, the male will bring food to the female and young during the first few days. The young bluebirds will fledge in 15 to 20 days. The adult birds will continue to feed the fledglings, though the young will be able to find food on their own in about two weeks.
In late March and April, tree swallows, chickadees, tufted titmice, and white-breasted nuthatches and woodpeckers will also be looking for appropriate cavities in which to nest. All these birds have nesting cycles that are similar. The key to attracting bluebirds and these other birds to your yard is to put up nest boxes, and have food and water available.
Most of these birds will hunt insects when they become available, but feeding seed and suet to birds will sustain them in these early months and help supplement their insect diet during warmer months. So if you have bird feeders now, you are ahead of the game. If you want to attract bluebirds with food, or help them during the nesting process, you can provide mealworms in a feeder near the nesting box.
Many other birds enjoy mealworms as well. A readily available supply of mealworms will create less stress for the female that leaves the nest in search of food and will help the male provide a more readily available source of nourishment for his mate and offspring. Feeding mealworms will help increase the success rate for nesting bluebirds, and other birds in your yard as well.
Another key to attracting and keeping bluebirds, and other nesting birds, is to provide water. A birdbath will supply water needs if you are not near a natural brook or stream. Planting shrubs and bushes that produce berries also provides natural food and a source of water for birds, especially during the colder months when insects aren’t available.
Bluebirds in our area can have two and, sometimes, three broods during the season. Many other birds have second broods as well. So if birds don’t find your house right away, they may choose it for a future brood as late as June or July.
Nest boxes, food and water will help to attract bluebirds and other cavity nesting species to your yard this spring and summer, bringing you much bird watching enjoyment!
Steve Grinley is the owner of Bird Watcher’s Supply and Gift in the Port Plaza, Newburyport. Email him at Birdwsg@comcast.net. On the web: www.birdwatcherssupplyandgifts.com.