Midsummer visitors to our home often look about in confusion when they hear the sound of chattering baby birds coming from the closed off fireplace in our living room. Having kept this home warm for many years, the fireplace finally fell into disuse for heating 20 years ago due to damage to brick and mortar after one chimney fire too many. But the chimney swifts, who have nested there for many summers, continued using it even after we stopped.

This year, the chattering began in mid July. According to online sources, it takes the chicks about a month to fledge. Good parents, chimney swifts spend all their waking hours gobbling flying insects in mid air to feed to their young. In and out they glide, with grace and agility, regurgitating a stored up ball or bolus of digested insects.

The same is true when they build their nest; they never land, but grab onto small twigs while in active flight, bring them back and attach them to the chimney wall with glue made from their own saliva. They eventually produce a semicircular nest of twigs attached by spit, which seems incredible, but that actually holds extremely well attached to reasonably clean firebrick and mortar.

In a chimney coated with glassy, baked on creosote, the nest may break off and fall to the bottom, which makes the sound of twittering even louder. Our birds always seem to make it out eventually, but by then we have become inured to the sounds. (Could you turn the sound up? I can’t hear the TV.)

 Despite the volume of noisy chattering, a single chimney or other hollow structure will contain

only one active chimney-swift nest, although non breeding birds may come in to roost at night. Sometimes referred to as “flying cigars,” chimney swifts may be mistaken for bats because of their flight pattern. About five inches long, with graceful swept back wings, their dark coloration makes them difficult to observe since they only land when inside their protective chimney. Claw like feet and tiny spurs at the end of their tail feathers allow them to cling to rough surfaces.

In the late summer or early fall, swifts begin to gather in suitable locations to roost by the hundreds before they return to warmer climes, in their case, the Amazon Basin of Peru, which makes for an annual round-trip migration of about 6000 miles. Vincejo de chimnea flies in the skies south of the equator while snow flies in New Hampshire.

Watching these creatures all summer long, I begin to feel proprietary towards them. They live in our chimney for six or more weeks, after all. But, knowing of their other home reminds me these tiny creatures are not anyone’s property but important beings in the global web of life.

Before European settlers arrived, chimney swifts lived in hollow trees. Audubon called them American Swifts. As pioneers headed west, clearings and settlements became more common to North America, hollow trees became harder to find, and the swifts turned more and more to man made chimneys. As the Industrial Revolution spawned factories, mills with chimneys began serving as attractive nesting structures for swifts. Soon people began to refer to them as chimney swifts, a name that stuck. Their adaptation to chimneys actually increased their numbers in the first part of the twentieth century. Today, their numbers have begun waning again due to the lack of masonry chimneys. Wildlife groups around the country are working to build new nesting towers for these voracious insectivores that glide through our skies in search of food for their nestlings and themselves.

The summer begins with little fluttering sounds as the nesting pair explores and prepares their nest. My husband and I just roll our eyes and hope that this summer’s nest will stay on the wall of the chimney and that the babies will fledge quickly. Inevitably though, and this year has been no exception, the nest eventually winds up in the bottom, with four to six twittering babies waiting impatiently for Mum and Dad to bring the chow. Removing the baby birds from the chimney would spell a sure death for them; their parents won’t feed them outside of the nesting site. (Disturbing an active chimney swift nest is also illegal under the federal Migratory Bird Treaty Act.)

So the chattering continues, and soon we don’t even notice. As the tiny birds grow stronger, they leave the nest to cling to the walls of the chimney and practice beating their tiny wings until they pant with exhaustion. One day, they will actually fly or crawl to the top and practice flying in circles around the house and chimney.

By mid-August, the chattering ceases, the TV volume decreases, and we breathe a sigh, not of relief, but of satisfaction. Another summer, another brood off to Peru.

By Helen Downing, Master Gardener