Saw-whet owls are small, secretive owls that breed across North America. In fall and winter, saw-whet owls move south in large numbers during migration. This has led many people to ask: do saw-whet owls migrate?
Quick Answer: Yes, saw-whet owls do migrate
Saw-whet owls are migratory birds. Each fall, saw-whets that bred in Canada and the northern United States migrate south to wintering grounds in the southern United States and Mexico. In spring, they make the return journey back north. Banding studies have shown that some individual saw-whet owls migrate up to 1,000 miles between their breeding and wintering grounds.
What is saw-whet owl migration like?
Saw-whet owl migration occurs primarily at night in fall and winter. The small owls tend to migrate along mountain ridges and coastlines, avoiding long water crossings over the Great Lakes or Gulf of Mexico. Migration peaks in October and November as the owls move south, and again in March and April as they return north.
Saw-whet owls migrate singly, not in flocks. But during peak migration, dozens or even hundreds of saw-whets may pass a single spot each night. At banding stations, it’s common for hundreds of saw-whets to be banded each fall.
What flyways do saw-whet owls use?
There are four main flyways used by saw-whet owls in North America:
- The Atlantic flyway along the east coast
- The Mississippi flyway through the Great Lakes and Midwest
- The Central flyway between the Rocky Mountains and Great Plains
- The Pacific flyway along the west coast
Saw-whets that breed farther north tend to funnel south through these main flyways. Those that breed farther south may not migrate as far.
Where do saw-whet owls migrate to and from?
Saw-whet owls that nest in Canada migrate south into the United States for winter. Those that breed in the northern U.S. migrate shorter distances south. And saw-whets in the southern U.S. are often year-round residents that don’t migrate at all.
In general, the breeding, migration, and wintering range looks like:
- Breeding grounds: Alaska, Canada, northern U.S.
- Migration: Through the U.S. along the Pacific, Central, Mississippi, and Atlantic flyways
- Wintering grounds: Pacific Northwest, southern U.S., Mexico
Breeding grounds
Saw-whet owls breed across Alaska, Canada, and the northern United States. Their breeding range extends as far north as central Alaska and across Canada to Newfoundland and Labrador. In the Lower 48, they breed across the northern U.S. from Washington to Maine.
Migration routes
During fall and spring migration, saw-whets move south through all of the lower 48 states. Migration hotspots include:
- Pacific Northwest along the Cascades and Coast Ranges
- Great Lakes region
- Appalachian Mountains
- Central U.S. from the Rockies to the Mississippi River
Wintering grounds
The core wintering range of saw-whet owls extends from the Pacific Northwest through the southern U.S. and into Mexico. Northern populations migrate farther south, while southern saw-whets may not migrate at all. Important wintering areas include:
- Pacific Coast from southern Alaska to Northern California
- Southern U.S. from California to the Carolinas
- Southernmost U.S. and Mexico
How far do saw-whet owls migrate?
The distance saw-whet owls migrate depends on where they nest. Northern breeding populations migrate the farthest. For example:
- Saw-whets in Alaska may migrate 1,000 miles or more to the Pacific Northwest.
- Canadian saw-whets often migrate 500-1,000 miles to the U.S.
- In the northern U.S., migration distances range from a few hundred to 500 miles south.
- Southern saw-whets are often year-round residents.
The longest recorded migration by a banded saw-whet owl is 1,053 miles between Washtucna, WA and Saskatoon, SK.
When do saw-whet owls migrate?
Saw-whet owl migration peaks in October and November heading south, and again in March and April heading north. But their movements are influenced by weather and food supplies, so migration timing can vary.
Fall migration
Most saw-whet owls migrate south from September through November. In a typical fall, migration peaks in October and the first half of November. Some key events in fall saw-whet migration include:
- Early migrants begin moving south in September
- Peak migration from mid-October to mid-November
- Movements continue into December
Cold snaps with northern winds often spur large migration events. Saw-whets migrate more steadily in mild falls.
Spring migration
Saw-whet owls generally migrate north from March to May. In an average spring, migration peaks in April. Some key events include:
- Early migrants depart wintering grounds by late February and March
- Peak migration in April
- Some linger into May
Warm southerly winds help boost migration. Movements are more drawn out in cooler, wetter springs.
How do saw-whet owls migrate?
Saw-whet owls are nocturnal migrants. They fly under the cover of darkness and rest during the day. Saw-whets migrate solo, not in flocks. Even at peak migration spots, owls pass one-by-one rather than in groups.
Saw-whet owls make their migratory journeys by powered flight. They flap their small rounded wings continuously to propel themselves south each fall and north in spring. Their flight speed averages 15-25 mph, but can reach 40 mph with a tailwind.
Stopover habitat
During migration, saw-whet owls seek out small forested areas to rest and refuel during the daytime. Ideal stopover spots provide:
- Forest cover to roost in during the daytime
- Good habitat for hunting small mammals and birds
- Protection from predators like hawks and falcons
Stopover habitats include small woodlots, forest edges, and suburban wooded parks imbedded in agricultural or developed areas.
Barriers and hazards
Saw-whet owls confront various barriers and hazards during migration including:
- Large bodies of water – sawwhets avoid making long water crossings over the Great Lakes, Gulf of Mexico, etc. This funnels them into coastal and inland routes.
- Deserts and mountains – saw-whets are less common in migration across large deserts and high mountains. They seem to prefer lower elevation routes.
- Bad weather – headwinds, precipitation, and low cloud ceilings can force migrating saw-whets to stop early and seek shelter.
- Human structures – collisions with buildings, towers, and vehicles take a toll on migrating saw-whets.
Threats faced by migrating saw-whet owls
Saw-whet owls face a variety of natural and human-caused threats during migration, including:
Collisions with human structures
Windows, towers, and vehicles account for many saw-whet deaths during migration. Their low, fast flight puts them at risk of collisions.
Habitat loss
Loss of stopover habitats due to human development deprives saw-whets of places to rest and hunt during migration.
Climate change
Changing weather patterns could disrupt timing of migration and food supplies along migration routes.
Predators
Larger owls and hawks prey on migrating saw-whets. Raccoons, foxes, and cats also take roosting saw-whets.
Exhaustion
Exhaustion and starvation are risks, especially for young, inexperienced birds on their first migration.
Tracking saw-whet owl migration
Saw-whet owl migration has been studied using banding and tracking techniques:
Banding
Capturing and banding saw-whets provides information on migration timing, routes, age and sex ratios. Hundreds or even thousands may be banded in a season at some stations.
Radio-telemetry
Studies have radio-tagged saw-whets to track individual migration routes and behavior.
Motus wildlife tracking system
Automated radio towers are used to detect tags on migrating saw-whets and document stopovers and flight paths.
Notable saw-whet migration sites
Some well-known saw-whet owl banding stations and migration hotspots include:
Location | State/Region | Seen Per Year |
---|---|---|
Lake Superior | Minnesota | 1,000-2,000 |
Whitefish Point | Michigan | 500-1,500 |
Cape May | New Jersey | 100-300 |
Allegheny Front | Pennsylvania | 500-1,000 |
Hollywood Beach | Georgia | 100-200 |
Interesting saw-whet migration facts
- Saw-whet owls get their name from their repetitive, saw-sharpening toot toot toot call, which sounds like they are whetting a saw.
- Despite being a widely distributed species, saw-whet owls were not confirmed to be migratory until 1959 when 119 birds were banded in one night on Brennan Hill, PA.
- Saw-whets migrate south later in fall than many other owl species and migrate north again earlier in spring, sometimes even when snow is still on the ground.
- Most saw-whets are migratory, but those in coastal California, southern Texas, and Florida are often year-round residents.
- Juvenile saw-whets on their first southward migration sometimes wander east out over the Atlantic Ocean in the fall, vagrancy known as “fall drift.”
Conclusion
In conclusion, most saw-whet owl populations are migratory, moving south out of Canada and northern states in fall and returning north again each spring. Saw-whet owl migration occurs primarily under the cover of darkness as solitary owls make their way along the Pacific, Central, Mississippi, and Atlantic flyways. Peak migration takes place in October and November heading south, and again in March and April going north. Understanding migration patterns helps identify risks to saw-whet owls and target conservation efforts along their routes.