Words On Birds 03-13-26

 

     March marks the beginning of the real estate market for most birds. Yes, great horned owls are likely already on eggs in abandoned red-tail hawk nests, and screech owls are close to settling in on their favorite hole or nest box. The warm weather that we experienced earlier in the week has bluebirds preparing to scout for nest boxes. A few tree swallows have already been spotted on Plum Island and before too long, they too will soon be searching for residences.

 

     It is, therefore, time again to provide my refresher on attracting bluebirds and tree swallows. Now is the time to put up a house or clean out existing ones, as bluebirds will start nesting by late March or early April. 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 spring and even early summer. Most swallows arrive in late March and early April, and they usually have one nesting, but sometimes two.

 

     Bluebirds or tree swallows nest in similar houses, so you’ll want a nesting box designed for them. Though there are different styles, most have a 1 1/2-inch opening that is about six inches above a four-inch square floor. Some have 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. Other popular styles include the Peterson box, which is wedge-shaped with a sloping, overhanging roof that helps deter predators, and the Kentucky style, with a long entrance slot at the top, said to deter house sparrows.

 

     All bird houses should be easy to open for maintenance, and for monitoring the birds during the nesting season if you so choose. Bluebirds and swallows like an open area for feeding, so placement of 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. Further distance from trees may be necessary if house wrens are present. In an open field, a tall stick in the ground near the house can be a favorite perch for bluebirds while they forage for food or guard the house. Direct placement onto a fence post or tree can also be successful, but more difficult to discourage predators.

 

     The house should be placed between four and seven feet high, facing away from foul weather winds. Like many birds, bluebirds are territorial. That is, they will not allow another pair of bluebirds to nest too close. If you are putting up multiple houses, they should be spaced about 100-200 feet apart. 

 

     The tree swallows, once they arrive, may compete for the same house as bluebirds. Swallows are also beautiful birds. They eat flying insects, so they are beneficial as well. For that reason, many people place pairs of houses within 10-25 feet of each other to allow bluebirds and tree swallows to nest side by side. This way, both species’ presence helps control both crawling and flying insects.

 

     These two species also help protect each other from the aggressive house sparrow, their number-one competitor. House sparrows often take over bluebird nesting boxes and will even kill adult bluebirds or swallows in the process. Because house sparrows are so aggressive, houses should be placed as far away from buildings as possible and they should be monitored on a regular basis, especially early in the nesting cycle. If sparrows are present, their nesting material should be removed. If sparrows become a real problem, trapping the sparrows may be necessary.

 

     Once bluebirds arrive, you can put out mealworms to encourage them to stay. You will be ahead of the game if you have been feeding bluebirds in your yard regularly. Once the bluebirds begin nesting, you can continue to help them by providing mealworms (live or dried) in a nearby feeder. This will minimize the time the male spends away from the nesting box, where he can protect his mate from intruders. 

 

     Females lay one pale blue egg a day for a total of 3-7 eggs, typically 4 or 5. The female does most of the incubating and only leaves the nest periodically to feed. Thus, having mealworms nearby will help shorten her absence from the nest and further increase their chances for a successful brood. They incubate for about two weeks and nestlings fledge two to three weeks after that. 

 

     Tree swallow eggs are white and they may take a bit longer to hatch. Swallows also take a longer time to fledge as they need to be able to fly when leaving the box.

 

     Boxes should be cleaned after fledglings leave the nest as the adults may use the same house for another brood. Houses should also be cleaned after every nesting season and checked again just before spring. Once established, bluebirds and tree swallows will return to the same area every year and more boxes can be added for returning offspring.

 

     These beautiful birds have made a comeback in recent decades due to efforts of homeowners providing suitable nesting habitats for them. In turn, the bluebirds and swallows share with us their beautiful colors and song, and they help naturally control insects in our yards!