I had chirping in my chimney too, and what you’re hearing is most likely a family of chimney swifts living in your chimney flue.
Chimney swifts are widespread breeding visitors to much of the eastern half of the U.S. and the southern reaches of eastern Canada. Chimney swifts are tiny birds that migrate from Peru in late March. They leave in early November, about the time the leaves start to change color, and before the first frost.
The migratory bird treaty act protects chimney swifts.
Therefore, they (birds and nests) cannot be legally removed from your chimney without a federally-issued permit. You will have to wait until after the adults and juveniles leave your chimney to have your chimney cleaned, and a chimney cap installed.
Chimney swifts are most often unnoticed until the time when their young are grown up enough to make chirping sounds when the parents bring them food. During this time, the chirping sounds can be very persistent and loud. However, this time is short-lived. Newly lain eggs will take up to six weeks to reach maturity. They only lay one brood per year, so once this family leaves, your chimney will be bird free for the winter months. They will return to the same location year after year. If they are a disturbance to you, cleaning your chimney and installing a chimney cap, once they are gone (mid-November), will keep them from returning next year.
We had chirping in my chimney…
I had chimney swifts come to my house year after year for twenty-two years, and I thoroughly enjoyed them. It’s amazing watch how fast the adults fly in and out of the flue feeding the babies. One year however, I forgot to close the damper on my fireplace and a baby chimney swift fell from the flue into the fireplace. The little guy was fully feathered and could fly. I very, gently cupped it in a dish towel, went to the front door, and with an upward motion released it into the air. It was a wonderful feeling watching it get lift, and fly away.
The young are able to climb up the walls of the chimney. If a baby were to fall down, the best thing to do would be to gently guide it to the walls of the chimney and allow it to climb back up to the nest.
Chimney swifts generally mate for life and both the male and female are involved in building the nest, incubating the eggs, and feeding the young. They build a half cup nest out of twigs broken from the tips of tree branches. These twigs are glued together with saliva to the inside wall of a chimney, hollowed-out tree or other cavity.
Chimney swift breeding time…
The female normally lays three to five white eggs with an incubation period of 18-21 days. The hatchlings are pink, and completely naked at birth. They have sharp claws which enable them to cling to textured surfaces. Within a few days, black pinfeathers begin to appear, and within 8-10 days these feathers unfurl. The young are able to climb even before their feathers emerge. By 15-17 days of age, their eyes begin to open. By the time the baby swifts are 21 days old, they will cling tightly to the nest or chimney wall, rear back and flap their wings rapidly until they are out of breath. This is important exercise to strengthen their wings for flight. Twenty-eight to 30 days after hatching, the young swifts will leave the safety of the nest for their first flight.
At the end of the breeding season, the swift’s communal instincts peak prior to fall migration. When it’s almost time to migrate, hundreds, even thousands gather together at suitable roost sites before the time is right for their long flight back to Peru.
Chimney swifts are approximately five inches in length and have a dark, sooty, brown body with a paler throat and upper breast. The male, female and juvenile all look the same, with the males being slightly heavier on average. They are built for speed with narrow, slightly bowed, long wings (11”-12”), with short, massive wing bones. Their wings extend as much as 1.5” beyond the bird’s tail when folded, and their wingtips are pointed, which helps to decrease air turbulence during flight. They are often confused with bats because of their fast, erratic flight.