The northern rough-winged swallow (Stelgidopteryx serripennis) is a small songbird found throughout much of North America. It is a member of the swallow family Hirundinidae, known for their speed, agility, and adaptability. The northern rough-winged swallow gets its name from the serrated edges of its primary wing feathers. This species breeds across Canada and the United States and migrates to Mexico, Central America, and the Caribbean for the winter. The northern rough-winged swallow inhabits open country near water and nests in burrows, crevices, or artificial structures. Let’s explore some fascinating facts about this widespread yet underappreciated bird!
Physical Description
The northern rough-winged swallow is a small, slender swallow approximately 5-6 inches (13-15 cm) in length with pointed wings and a medium-length forked tail. Adults have brown upperparts and pale underparts, with a brown cap and pale throat. The wings are darker brown with pale “windows” when spread. The outer primary feathers have stiff serrations that produce a humming sound in flight. The sexes are similar in appearance. Juveniles have paler upperparts and whiter underparts with dusky streaks on the breast. Rough-winged swallows have a swift, erratic flight pattern consisting of quick zig-zagging turns interspersed with glides. Their call is a dry rattle or chip note.
Size and Weight
Length: 5.1 – 5.9 in (13 – 15 cm)
Wingspan: 11.8 – 13.0 in (30 – 33 cm)
Weight: 0.4 – 0.7 oz (11 – 21 g)
Plumage
– Brownish upperparts
– Pale underparts with some dusky streaking on breast
– Brown cap contrasting with pale throat
– Forked tail with white outer tail feathers
– Dark brown wings with pale “windows” when spread
Distinguishing Features
– Serrated outer primary wing feathers produce humming sound in flight
– Swift, darting flight with zig-zagging turns
– Small size, pointed wings, medium-length forked tail
– Pale throat contrasts with brown cap
Habitat and Range
The northern rough-winged swallow inhabits open and semi-open environments near bodies of water across much of North America. Its breeding habitat extends from Alaska and Canada south throughout the continental United States to Florida, the Gulf Coast, and central Mexico. This species winters in the southernmost United States, Mexico, Central America, and the Caribbean islands. Preferred breeding areas include meadows, agricultural fields, wetlands, lakes, rivers, and coastal habitats. Northern rough-winged swallows nest in burrows, crevices, cracks, holes, and cavities, both natural and manmade. They are often found nesting in association with bank swallows or belted kingfishers along earthen banks, quarries, or road cuts.
Breeding Range
– Alaska across Canada
– Throughout the continental United States south to Florida and Mexico
Winter Range
– Southern U.S.
– Mexico
– Central America
– Caribbean islands
Year-Round Range
Some northern rough-winged swallows are permanent residents along the southern Atlantic and Gulf coasts of the U.S. as well as southern California.
Preferred Habitats
– Open country near water
– Meadows, fields, wetlands
– Lakes, rivers, coasts
– Nest in burrows, crevices, cavities in banks, cliffs, structures
Migration
The northern rough-winged swallow is one of the later swallow species to arrive on its breeding grounds, typically showing up in April and May. It is also one of the earliest swallows to depart for its wintering grounds, leaving starting in July through September. This species migrates during the day, traveling in loose flocks. Northern rough-winged swallows have one of the longest migrations of any North American swallow, as some travel between Alaska and South America. However, this species exhibits leap-frog migration, meaning that northern breeding populations migrate shorter distances compared to southern populations. Birds that breed farther north tend to winter farther south.
Spring Migration
– Arrives on breeding grounds April – May
– Travels in loose flocks
– Northern populations migrate shorter distances than southern ones
Fall Migration
– Begins departing July – September
– One of the earliest swallows to migrate south
– Travels to southern U.S., Mexico, Central America, Caribbean
– Makes one of the longest swallow migrations in North America
Diet
The northern rough-winged swallow primarily feeds on insects caught during sustained flight. Its diet is composed mostly of small flying insects such as flies, bees, wasps, ants, and beetles. This species forages over open country, fields, water sources, and in wooded edges. Northern rough-winged swallows drink by skimming across water surfaces while flying. They occasionally feed on emerging aquatic insects such as mayflies, stoneflies, and caddisflies. This adaptable species will also eat moths, grasshoppers, crickets, leafhoppers, and other insects. Swallows feed almost constantly during daylight hours, needing substantial food intake to support their high metabolic rates required for flight.
Primary Prey
– Flying insects
– Flies, bees, wasps, ants, beetles
Other Prey
– Aquatic insects (mayflies, etc.)
– Moths, grasshoppers, crickets
– Feeds mostly while in sustained flight
– Drinks by skimming across water in flight
– Feeds almost constantly during daylight
Reproduction and Nesting
The northern rough-winged swallow breeds in solitary pairs, not in colonies. Nest sites are often reused from previous years. Courtship displays include hovering flights by the male near the nest site. Northern rough-winged swallows are socially monogamous and assumed to mate for life, although divorce and re-mating does occur. Pairs raise one brood per season. The female constructs the nest in a burrow or cavity and incubates the eggs. Both sexes feed the young.
Courtship
– Male performs display flights around nest site
– Socially monogamous, likely mate for life
– Divorce and re-mating are known to occur
Nest Sites
– Burrows, crevices, holes in banks or structures
– Often reused from previous years
– Occasionally shared with other species
Nest Construction
– Nest built by female with grasses and feathers
– Lined with softer feathers, hair, plant down
– Constructed in burrow or cavity
Clutch Size
– 4-7 white eggs
– Incubated by female ~14 days
Parental Care
– Female incubates eggs
– Both parents feed nestlings
– Nestlings fledge ~18-25 days after hatching
– Raise one brood per season
Conservation Status
The northern rough-winged swallow has a large range and abundant total population estimated at 34 million birds. Its population appears to be increasing overall according to data from the North American Breeding Bird Survey. Partners in Flight estimates a global breeding population of 28 million with 99% living in the U.S. and Canada. Because of its large and growing population, the northern rough-winged swallow is evaluated as Least Concern on the IUCN Red List. Major threats include pesticide use, climate change, and competition with invasive species like European starlings for nest sites. But this adaptable species has proven able to thrive among human alteration of the landscape. It readily uses bridges, culverts, and drainage pipes for nesting. Maintaining open habitats near water will help provide nesting and foraging areas. Limiting pesticide use will also benefit northern rough-winged swallow populations.
Population Status
– Total global population: ~34 million
– Population increasing overall
– 99% of population breeds in U.S. and Canada
IUCN Conservation Status
Least Concern
Major Threats
– Pesticide use
– Climate change
– Competition with invasive species for nest sites
Conservation Actions
– Maintain open habitats near water
– Limit pesticide use
– Monitor and manage invasive species
– Protect nesting and foraging areas
Fun Facts
Here are a few fun and interesting facts about the northern rough-winged swallow:
- The serrated outer wing feathers help reduce turbulence and may improve flight maneuverability.
- The pale “windows” in the wings may serve as signals important during courtship displays.
- Rough-winged swallows rub their serrated wings together to produce the humming sound during flight.
- Oil secreted by a gland in the nestlings produces the “swallow smell” in nest burrows.
- Young swallows flap their wings up to 12,000 times a day to build flight muscles before fledging!
- Swallows sunbathe on early mornings by perching and orienting their bodies toward the sun.
Conclusion
The northern rough-winged swallow is a fascinating and handsome little songbird. This common species thrives near human settlement as long as suitable nesting sites and insect prey remain available. Its adaptable nature, identifiable fluttering flight, and willingness to use manmade structures have made the northern rough-winged swallow a beloved backyard bird. With ample food and nesting options, this species should continue brightening our skies with its swift, graceful flight for years to come. The northern rough-winged swallow remains a vibrant part of North America’s avifauna.