BirdAnalyst
Species · BBS 2026 Release · 1966–2025

Northern Rough-winged Swallow Population Analysis

HirundinidaeAerial insectivoresStelgidopteryx serripennis

Northern Rough-winged Swallow has risen sharply: up 54% on the route-weighted index since 1968.

+54%Since 1968TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
3,373RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
59Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

About the Northern Rough-winged Swallow

The Northern Rough-winged Swallow (Stelgidopteryx serripennis) is a North American member of the Swallows & Martins (Hirundinidae). In this analysis it is grouped with the aerial insectivores.

Size
4.5–8 in long (12–20 cm) — a small, streamlined bird (typical for the family)
Habitat
Open airspace over fields, water and towns; nests in cavities, earthen banks or on structures.
Diet
Flying insects caught on the wing.
Range
Recorded on 3,373 Breeding Bird Survey routes across 49 states, most concentrated in the Appalachian Mountains.
Family
Hirundinidae · Aerial insectivores

Notable Northern Rough-winged Swallow TrendsNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

long arc increasecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

Northern Rough-winged Swallow has risen sharply in surveyed states: up 54% on the route-weighted index since 1968.

Northern Rough-winged Swallow Population Forecast

If the recent trend holds, Northern Rough-winged Swallow is projected to rise about 33% by 2030 — from 1.3 in 2025 to a central estimate of 1.7 (95% range 0.86–2.5). A 5-year backtest shows a typical error of ±34.3%, with 100% of held-out values landing inside the 95% band.

+33%Change by 2030TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
1.7Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.86–2.595% range95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
±34.3%Backtest errorBacktest errorTypical error when we hold out the most recent years, forecast them, and compare to what actually happened. Lower means a more trustworthy projection.Full methodology →
If the recent trend holds, Northern Rough-winged Swallow is projected to rise about 33% by 2030 — from 1.3 in 2025 to a central estimate of 1.7 (95% range 0.86–2.5). A 5-year backtest shows a typical error of ±34.3%, with 100% of held-out values landing inside the 95% band.19662030
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →95% low95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →95% high95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
20261.70.852.5
20271.70.852.5
20281.70.862.5
20291.70.862.5
20301.70.862.5

Where the Northern Rough-winged Swallow Is Detected

BBS routes recording Northern Rough-winged Swallow, sized by most recent count.

Northern Rough-winged Swallow Population Trend by State

Northern Rough-winged Swallow population trend by state.
TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Alabama+46%1968108
Alaskainsufficient datan/a2
Arizona-44%197061
Arkansas+773%196950
California-49%1970204
Colorado-30%1970118
Connecticut+225%196918
Delaware-60%196813
Florida-32%196975
Georgia+22%196896
Idaho-34%197055
Illinois+394%1968104
Indiana+81%196864
Iowa+5%196938
Kansas+78%196964
Kentucky+43%196864
Louisiana+125%196965
Maine-88%197227
Maryland+85%196867
Massachusetts+25%197029
Michigan+9%196887
Minnesota-57%196967
Mississippi39×196967
Missouri+310%196985
Montana+50%197087
Nebraska+276%196964
Nevada+258%197036
New Hampshire-44%196821
New Jersey+28%196928
New Mexico-13%197052
New York+18%1968104
North Carolina+28%196899
North Dakota+103%196946
Ohio+61%196889
Oklahoma+51%196967
Oregon+10%1970102
Pennsylvania+86%1968122
Rhode Island-17%19874
South Carolina+111%196844
South Dakota+32%196950
Tennessee+163%196851
Texas+92%1969157
Utah-44%197079
Vermont+28%196924
Virginia-21%196866
Washington-29%1970103
West Virginia-22%196858
Wisconsin-40%196891
Wyoming-34%1970101

Northern Rough-winged Swallow Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Northern Rough-winged Swallow population trend by Bird Conservation Region.
TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Northern Pacific Rainforest-66%1970104
Great Basin-19%1970205
Northern Rockies+2%1970179
Prairie Potholes-4%1969104
Boreal Hardwood Transition-74%196885
Lower Great Lakes / St. Lawrence Plain-8%196880
Atlantic Northern Forest-52%196888
Sierra Nevada-70%197224
Southern Rockies / Colorado Plateau-37%1970165
Badlands and Prairies+35%1969103
Shortgrass Prairie-75%197082
Central Mixed Grass Prairie+142%1969114
Edwards Plateau-9%197413
Oaks and Prairies-11%196966
Eastern Tallgrass Prairie+203%1968270
Prairie Hardwood Transition-16%1968154
Central Hardwoods+94%1968155
West Gulf Coastal Plain / Ouachitas-46%196977
Mississippi Alluvial Valley19×196958
Southeastern Coastal Plain+29%1968308
Appalachian Mountains+35%1968362
Piedmont+151%1968155
New England / Mid-Atlantic Coast+5%1968122
Peninsular Florida-63%197138
Coastal California-59%1970106
Sonoran and Mojave Deserts+65%197058
Sierra Madre Occidental-86%197022
Chihuahuan Desert-64%197733
Tamaulipan Brushlands-48%197020
Gulf Coastal Prairie-64%197223

Northern Rough-winged Swallow Conservation Status

Our route-weighted index shows it up about 54% since 1968. Aerial insectivores have fallen sharply across the continent, a decline widely linked to dwindling insect prey.

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14. Trend is a route-weighted relative-abundance index, not an absolute population.