Guide

Go seeBirds

Bank swallows nest in burrows in sandy riverbanks

May to July

Bank swallows, our smallest swallow, dig their own nest tunnels into steep sand or gravel banks, and a colony can riddle a bluff with dozens to hundreds of holes. From a canoe you can watch them zip in and out over the river, but Mass Audubon rates them strongly declining in Massachusetts, so this is a sight to enjoy from the water.

Why this time of year

Mass Audubon's atlas says bank swallows reach inland waters in numbers by May. At one studied Massachusetts colony, adults fed nestlings from late May to early August, most from mid-June to late July, and the last migrants usually leave by early September.

How to notice it

  1. On a river with steep, bare sand or gravel bluffs, look on the bank face for rows of small round holes, often near the top.
  2. Watch the holes for a few minutes: small brown-backed swallows with a dark band across a white chest dart in and out, and flocks fly low over the water catching insects.
  3. Listen for buzzy calls around the colony.
  4. Stay in your boat and keep off the bank; the colony nests in the bluff face.

Try this with kids: How many holes can you count in the bank, and can you see a swallow pop out of one?

Safety

  • Massachusetts requires canoeists and kayakers to wear a life jacket from September 15 to May 15, and youth under 12 years of age must wear one; the state recommends wearing a life jacket every time you are on the water.

Sources

  • massaudubon.orgMass Audubon Breeding Bird Atlas 1 account (Bank Swallow): smallest of the six swallows nesting in the state; first arrive on the coast mid-April, by May appear in numbers in the interior; colonies restricted to steep sandy or gravelly banks, bluffs along rivers, lakes, bays, ocean; colonies number tens to hundreds of pairs; at a colony studied, adults fed nestlings May 26 to August 5, most June 17 to July 21; fall migration begins mid-August, last transients usually depart by early September. read 2026-11-10
  • massaudubon.orgMass Audubon Breeding Bird Atlas 2 account: "Somewhat local and strongly declining", "Conservation action urgent"; excavates its own burrow in bare banks, colonies of dozens if not hundreds of pairs; nearly one-third fewer Confirmations in Atlas 2; Connecticut River Valley among the greatest decreases. read 2026-11-10
  • audubon.orgNational Audubon field guide: smallest of our swallows, usually seen in flocks flying low over ponds and rivers; nests in dense colonies in holes in dirt or sand banks, a tall cut bank may be pockmarked with several hundred holes; brown above, white below with dark chest band. read 2026-11-10
  • web.archive.orgMass.gov Massachusetts Boating Law Summary (Internet Archive copy dated 2025-12-17; mass.gov itself returns 403 to the fetch tool): "In Massachusetts, PFDs are required to be worn by: Youth under 12 years of age ... Canoeists/kayakers from September 15 - May 15". read 2026-11-10
  • web.archive.orgMassWildlife (DFW) Boating safety page (Internet Archive copy dated 2023-08-17): life jackets must be worn by canoeists and kayakers from September 15 - May 15 and youth under 12; "It is recommended that you wear a life jacket every time you are on the water." read 2026-11-10

Checked against these sources on November 10, 2026.

In the guide for May, June, July

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