A box of bluebirds

Nearly 15 years ago, the spirit moved me to build a bluebird box. Bluebirds were rarely seen in my wooded yard, but I was struck with hope that a nicely built box would attract a nesting pair.

Year after year, the box went unused.

Some years, we spotted bluebirds inspecting the box. Once or twice, they seemed to actually start a nest, but then would vanish.

Until this year.

A parent feeds the chicks.

A bluebird pair not only built a nest, but laid eggs and is now in the midst of feeding chicks that are about to fledge.

What happened? Here’s my theory.

Last year, another spirit moved me to clean up the back edge of the yard, a 10-foot-wide strip along a stone wall that was filled with fallen trees, rambling wild shrubs, tall wildflowers that others might call “weeds,” and piles of brush from years of cleaning up after hurricanes and winter storms, seasoned with discarded Christmas trees and wreaths. The area had been allowed to run wild and the brush piles to grow for decades.  The nesting box was on a post at the edge of this strip.

My excuse for allowing this mess to exist was to consider it a sort of backyard wildlife refuge. Indeed, many birds, reptiles, amphibians, and small mammals could be spotted there — not to mention neighborhood cats in search of rodents. (Other hunters included Cooper’s and Red-tailed Hawks, and nice, long garter snakes.)

However, the wildlife also included House Wrens, mortal enemies of bluebirds. 
The wrens could often be seen hunting insects in and about the brush piles. They may have nested there, too.

House Wrens do not like to share their territories with other birds, and often chase away potential neighbors. Being cavity nesters like the bluebirds, they also might grab the nesting box for themselves. At the very least, they would chase the bluebirds away.

Sometimes, as they are wont to do, the House Wrens would fill up the inside of the box with sticks, making it unusable for nesting. Many was the autumn that I would clean out a box crammed top to bottom with twigs.

I believe that clearing the mess not only made the area less attractive to wrens, it also opened up the yard, making it more attractive to bluebirds. They like open fields for bug hunting — and, probably, for keeping an eye out for predators.

My backyard “wildlife refuge” may be gone, but I don’t feel bad. On the other side of the stone wall is an acre of woods and wetlands, full of wild things.

And my yard now has bluebirds.

Bundling bluebirds

A correspondent told me a few years ago about a remarkable example of birds’ dealing with the cold.
“Recently, on a day when outside looked very white as snow was falling and already covering the ground, my husband and I witnessed a burst of color. Late in the afternoon, we saw about eight bluebirds sitting in the tree near our birdfeeders. Much to our surprise, some of them visited our feeders. This was our first experience at seeing bluebirds do this so we knew they must be very hungry.
“Most interesting, however, was what happened as the sun set. We witnessed a well-organized entry into a bluebird house at the edge of our yard. At least five of the birds seemed to squeeze themselves into the little house. Since that evening, we have observed this behavior several more times. We are delighted to provide shelter for our little friends.”
A number of species practice communal “bundling,” as the old New Englanders called snuggling on a cold winter’s night, but this was the first time I’ve heard of bluebirds doing it.
A check of Arthur C. Bent’s venerable and huge (21 volume) series, Life Histories of Familiar North American Birds, provides some interesting accounts of bluebirds in similar situations.
Bent quotes an item in a 1937 Springfield, Mass., newspaper, "Mr. Cross of Huntington has a photograph of 22 bluebirds together which, caught in a heavy spring snowstorm, lived upon sumac berries and, between feedings, snuggled together, all fluffed up, on a small dead branch in the shelter of a building."
Bent quotes Edward H. Forbush reporting in 1929, "In western Massachusetts and in Vermont during the late spring storms, many bluebirds have died huddled together in hollow trees, where they sought refuge from fury of the gale. During a storm, a lady in Stowe, Vt., heard a bluebird calling in her living room and found two in the stove. They had sought shelter in the chimney and had come down the stovepipe."
But perhaps the most amazing story – if it can be believed – came from that 1937 Springfield newspaper: "On March 28, a pair of bluebirds came to the feeding station of Charles J. Anderson, 24 Eddywood Ave., Springfield, and after eating began to flutter and peck at the window. It was cold outside, so after talking to them through the glass, Mrs. Anderson let them in. The male was hardy, but the female manifestly required warmth. She was given warm milk to drink, and warbled her thanks. For three days, while the cold spell lasted, she returned periodically to get warm inside the room."

Multi-brood birds

“Do phoebes raise more than one brood a season? asks Flo Vannoni of Redding.

“A pair of phoebes nested over our sliding door and succeeded in fledging three babies,” she writes. “The babies left the nest about one week ago and since then, we had not seen parents or babies. Today one of the parents returned to where the nest had been – I had removed it. Is it possible they would start another nest?”

Many species have more than one brood in a season, as Mary Walsh of Ridgefield – who sent the accompanying shot of a second-brood bluebird chick – can attest.

“The baby bluebirds fledged last week from a nesting box on my property,” Mary wrote July 14. “It is the second brood this summer.

“I found one baby hiding out on the running board of my Sequoia. As I tiptoed within a few feet, the baby bluebird hopped away. It appeared to be struggling to fly… Mom and Dad were in the trees chirping away. I had to leave and he was gone when I returned home. I hope he took flight.”

Flo wondered whether her phoebes would start another nest. They probably would, and perhaps in the same location since they would likely have used the old nest a second time.

Eastern Phoebes are very loyal to nesting location. They not only use the same nest for their two broods in a season, but also tend to re-use it for several years. That is relatively unusual among songbirds, most of whom build new nests every year. Phoebes simply make repairs and spruce up the previous year’s nest – “waste not, want not” is apparently the motto of this avian recycler.

For many songbirds, whose offspring hatch relatively quickly and don’t take long to fledge, having two broods in a season in this part of the country is normal. There is plenty of time to raise two families, and then fatten up for the migration south or, for many year-round species, to stock up on food for the winter.

Studies have found that northern birds of a given species tend to have fewer broods than southern birds, yet all produce around the same number of young per season.

In the North, for instance, Eastern Bluebirds typically have two broods. In the South, because the warm, insect-filled season is longer, bluebirds often have three broods.

Nevertheless, both northern and southern bluebirds produce about the same number of offspring per season because bluebirds in the North lay more eggs per brood than bluebirds in the South. A pair of Connecticut bluebirds might have two nestings, each with five babies, while a North Carolina bluebird couple might have three nestings with three eggs each. The result is about the same.

Did the southern birds work harder? They had more nestings, but fewer mouths to feed at each. Moreover, they probably did not migrate as far, if at all, to set up home.

(Photo of bluebird parent arriving with food for babies is by Kevin M. Doyle.)