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Chimney swifts swirling into old chimneys at dusk before migration
When: August to September
In the weeks before migration, chimney swifts in eastern Massachusetts gather at dusk and pour into big old chimneys to roost, hundreds swirling in like water down a drain.
Why this time of year
Swift roosts in eastern Massachusetts build to their biggest in late August and early September, and most swifts have left for South America by mid-September, so this show does not wait.
How to notice it
- Pick out the tallest old brick chimney in town, on a school, church, mill, or downtown block.
- Arrive a little before dusk on a clear evening in late August or early September and watch the sky above it.
- Look for a chittering flock circling the chimney, then tightening into a funnel and dropping in; the whole show lasts about half an hour.
- Roosts change, so if a chimney stays quiet, try a different one on another evening.
Try this with kids: Can you count the swifts as they drop into the chimney before dark?
A roost is a place where birds settle in for the night.
Sources
- massaudubon.orgAutumn migration principally late August and early September; several hundred swifts circling then entering a roost at dusk, swirling into the chimney like a whirlpool over about half an hour; most Massachusetts swifts departed by mid-September.
- massaudubon.orgSwifts roost in large numbers in big chimneys or airshafts, while only single pairs nest in house chimneys.
In the guide for August, September