Imagine you are a bird. You fly through the air almost continuously, picking off bugs for your meal, or for your offspring.
If you care to look in a mirror you’d find a dark face, cigar-shaped body, curved wings and nearly no tail. More important, you’d have such small feet as to make them useless for perching on a branch.
You’d be a chimney swift.
On a summer’s day the warm air is filled with insects, some so small or so high in the sky you can’t see them. That’s when the chimney swift, newly arrived from its winter home in Peru, flies over towns and fields in that jerky way it has, calling with rapid, hard chips. Sometimes they can be right over your head or be so high up you can’t see them. But you can hear them, calling to each other as they swarm and eat.
Swifts are not swallows, which also soar through the air or strafe a field or pond seeking bugs. In New Jersey there are many types of swallows -- Tree, Barn, Northern Rough-winged and Bank. There is also the Cliff Swallow that I have seen them going to man-made replicas of their mud nests placed to draw them beneath the bridge between Lambertville, NJ and New Hope, Pa., over the Delaware River. There are also purple martins, the largest swallows, which now nest primarily in man-made boxes.
There are four types of swifts in North America, but only the chimney swift is found in the eastern part of the US. Here is how Roger Tory Peterson described the chimney swift in the celebrated 1947 edition of the Peterson Field Guide to the Birds, his important field markings italicized:
The chimney swift has been called a cigar with wings. It is a blackish swallow-like bird with long slightly curved stiff wings and no apparent tail …Unlike most other birds it does not appear to beat its wings in unison but alternatively -- such is the illusion at least (slow-motion pictures to the contrary notwithstanding). The effect is quite batlike. Their narrow wings fairly twinkle as they fly and they frequently sail between spurts, holding the wings bowed like a crescent. Swallows have gliding wing beats, they frequently perch on wire and twigs. Swifts never do.
As its name implies, these swifts fly very fast and they nest in chimneys. But they can also nest in “air shafts, sometimes silos, barns, attics, old wells, garages,” according to the Peterson field guide to Eastern bird nests. Every year, on the first Saturday in May, my friends and I visit central New Jersey and wind up in Lambertville to dine. That is always when I hear my first familiar chittering of swifts overhead. Not long after I usually hear them in my town, where I've seen them use the train station chimney after heating season is over.
That is one of the biggest hazards a swift faces -- where to build a nest and raise young. In pre-colonial time Chimney Swifts nested in hollow trees. Today very few natural nesting sites are used. During migration they roost communally; it's not unusual to see 1,500 or more using one industrial size chimney. In fact, it's a sight everyone should see. Go out just before dusk to a local school the last couple of weeks of September to look for a big roost site.
I’ve never seen a nest but here is how the Field Guide to the Nests, Eggs and Nestlings of North American Birds by Colin Harrison (which calls itself as “a book for bird-lovers, not for egg-collectors“) describes a chimney swift’s nest:
The nest is stuck to a vertical surface within a shaft, from just below the top aperture to 4-5 feet above the bottom. One or two additional adults may help a nesting pair. Shallow half-cup of short dead twigs broken off by the birds in flight and glued together and to the wall by saliva. There is no lining…
There is little security for a nest attached solely by saliva. Location is everything. Although swifts are one of the bird species that actually benefited from the intrusion of man into the forests, on unexpected cold May days -- we’ve had a few such days this year -- people have been known to use their fireplaces, which would ruin a nest. Birds building nests on walls could lose them in a heavy rain, like the many such rains we’ve had this spring.
Even though the chimney swift is not considered an endangered species, according to the Cornell Lab of Ornithology, there are people who want to help the swift because -- like the swallows or bats -- they are very good at controlling insects. They make a good alternative to man-made and harmful pesticides.
Maybe that’s what inspired Roy Hyzer of Eagle Scout Troop 351 of the Boy Scouts of America, of Basking Ridge in Bernards Township, to build a fake chimney on the grounds of its neighbor NJ Audubons' Scherman Hoffman Wildlife Sanctuary. The Chimney Swift nesting tower, is a 14-foot tall structure and is a community service project: providing a structure or nest tower to hopefully restore a population of Chimney Swifts to the forest community. It took over 100 hours and many Scouts to dig the foundation, build a frame and put on the siding.
But when I first saw it, in early May during the World Series of Birding, standing at the edge of the education center parking area, I wondered, isn’t it too low? Why would a swift want to come here?
Obviously, I wasn’t thinking like a swift.
Scherman Hoffman is up in the Bernardsville hills, so even next to the education center the fake chimney is elevated.
And when you are provided with a tall, sturdy structure that stands on stilts and has a narrow opening (both to keep out predators) but a wide body suitable for a nest, why should you look for a chimney?
This was proved to me when, in early June, I came back to Scherman Hoffman and found several chimney swifts flying close to the visitor center, obviously drawn by this Trump Tower of nest boxes.
Swifts breed beginning in mid-May, laying three to six eggs over several days before beginning incubation, according to records by Peterson and Harrison. I could’ve been seeing fledged young, or it could’ve been helpers assisting the parents getting the food.
It is exciting to see a manmade structure be so successful in its task, helping swifts while educating humans. After all, manmade structures put up in parks and backyards have helped the populations of bats, swallows (particularly purple martins) and bluebirds to rebound. (You can see Scherman’s many bluebird boxes when you take the Field Loop trail.)
And there may be other such projects to come.
During the World Series of Birding, when sanctuary director Mike Anderson and his team were counting birds as part of the Big Stay team, I was on the hawk platform with them when a barn swallow flew in, zipping around and annoying the house sparrows nesting underneath.
“I wonder how we can get them to nest here?” Mike said of the swallow.
Another call to the Eagle Scouts might be in order.