Words On Birds by Steve Grinley
Bluebirds in Search of Housing
March 10, 2023
By Steve Grinley
Bluebirds are already checking out nesting boxes in area towns. They are one of the earliest nesters, often starting their first brood in late March. Now is the time to put up a nesting box or clean out existing ones. Bluebirds have two and sometimes three broods in a season, so if they don’t move in right away, you might still attract them later in May and June.
For the best chance to attract bluebirds you’ll want a nesting box designed for them. Though there are many different styles, most have a 1 1/2-inch opening that is about five or six inches above a four-inch square floor. Some have wood extensions, or predator guards, over the hole to help deter squirrels, raccoons and large birds. Metal plates around the hole help prevent squirrels from chewing and enlarging the hole. If you plan to monitor the house during the nesting season, you should have one that is easy to open with minimal disturbance to the nest. Bluebirds like an open area for feeding, so placement of bluebird houses should be in or near grassy areas. It is best to place the house on a separate pole away from the tree line, preferably with a baffle on the pole. Direct placement onto a fence post or tree can also be successful, but sometimes more difficult to discourage predators. Bluebirds are territorial so multiple houses must be placed 200-300 feet apart to encourage multiple pairs to nest.
The male, along with female, will go 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. The male may sometimes “spend the night” in the cavity with the female.
The female will incubate the eggs for about 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.
Bluebirds hunt crawling insects like hawks. They will perch on a stick, low branch or fence post and wait for an insect to show itself. The bluebird then goes to the ground and pounces on its prey, and brings the food back to the nest.
If you want to attract bluebirds with food, or help them during the nesting process, you can provide mealworms, live or dried, in a feeder in proximity to the nesting box. 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 as well, in your yard.
The young bluebirds will fledge in fifteen to twenty 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. Since bluebirds may have multiple broods, sometimes young from the first brood will assist in feeding the young from the second or third brood. This may continue into the fall and the “family group” may linger into the following spring season.
Another key to attracting and keeping bluebirds is to provide water. A heated birdbath may attract them through the late winter or a shallow bath during the warmer months. Planting shrubs and bushes that produce berries also provides a natural food source for bluebirds, especially during the colder months when insects are not available.
So the key to attracting bluebirds to your yard is to have potential nest boxes, food and water. We can’t help but feel good when a pair of bluebirds take up residence in our yard!