Returning bluebirds are a welcome sign of spring鈥攂ut in many places, it鈥檚 up to people to give them a home. To keep populations healthy, people across the country to erect and tend bluebird boxes. Over the past few decades, they鈥檝e helped all three bluebird species鈥擡astern, Western, and Mountain鈥攔ecover from a declining population, says Geoff LeBaron, director of 爆料公社鈥檚 Christmas Bird Count, and in the years to come, they could help secure the bird鈥檚 future.
Bluebirds鈥攁nd more than in North America鈥攁re cavity nesters. Rather than make their own nests, these birds take advantage of existing nooks and crannies in trees. But today, as natural cavities have become fewer and farther between, bluebirds increasingly rely on human-made homes.
鈥淭here is no one single perfect, ultimate bluebird nestbox,鈥 according to the (NABS). But a good box should be made of untreated wood, and be able to be opened for monitoring and cleaning. to select an , or to make your own. If you place your box on a pole鈥攁nd , rather than trees to better protect against insects鈥攎ake sure to add a: raccoons and cats love bluebirds, too. (Bluebirds prefer to nest at the edges of forests and fields; they鈥檙e less inclined to shack up in city boxes.)
It鈥檚 important to monitor the boxes for unwanted residents鈥攃heck in on the box at least once a week to make sure other birds haven鈥檛 taken over the bluebirds鈥 home. European Starlings and House Sparrows are unwelcome in a bluebird house; these are both invasive species .
One way you can tell what species has taken up residence in your nestbox is by checking the or the variety of nesting materials. Bluebirds generally favor grasses and pine needles, though the specifics vary by geographic area. Mountain Bluebirds often add wool and deer hair, while Western Bluebirds like to add feathers and ribbons. In comparison, starling nests are bulky while sparrows use a looser jumble of materials.
If an invasive species takes over your bluebird box, you can remove the nests by hand (some birds will keep coming back and laying new eggs, so you can render eggs infertile ). But the invasive birds don鈥檛 like human activity, so just your presence might be enough to scare them off, LeBaron says. Putting up a pair of nest boxes, at least several feet away from each other, can ensure that there is a spot for the bluebirds even if starlings or sparrows set up camp, too.
Need one more reason why it鈥檚 particularly important to help these native birds? 爆料公社鈥檚 Birds and Climate Report spells bad news for both 鈥攑rojected to lose the majority of its winter range by 2080鈥攁nd 鈥攑rojected to experience severe loss in its summer range.
鈥淐limate change adds to the pressure on many of these species,鈥 says 爆料公社鈥檚 chief scientist, Gary Langham. 鈥淣estboxes [are] more important than ever to the long-term future of these vulnerable species.鈥
Once you set up your boxes, report any residents to to help scientists and other birders understand the cavity nester population.