Cliff Swallow
Cliff Swallow has surged: up 229% on the route-weighted index since 1968.
About the Cliff Swallow
A colonial swallow that builds gourd-shaped mud nests under bridges, culverts and eaves, the Cliff Swallow nests in dense colonies that can number in the thousands.
- Size
- 5–5.5 in long, about 0.7 oz (13–14 cm, 21 g)
- Habitat
- Open airspace over fields, water and towns; nests in cavities, earthen banks or on structures.
- Diet
- Flying insects taken on the wing, often in swarms.
- Range
- Recorded on 2,963 Breeding Bird Survey routes across 48 states, most concentrated in the Eastern Tallgrass Prairie.
- Family
- Hirundinidae · Aerial insectivores
- Conservation
- Least Concern
Notable Cliff Swallow Trends
Cliff Swallow has surged in surveyed states: up 229% on the route-weighted index since 1968.
Cliff Swallow Population Forecast
If the recent trend holds, Cliff Swallow is projected to rise about 21% by 2029 — from 15 in 2024 to a central estimate of 19 (95% range 13–24). A 5-year backtest shows a typical error of ±36.2%, with 40% of held-out values landing inside the 95% band.
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 18 | 13 | 24 |
| 2026 | 18 | 13 | 24 |
| 2027 | 19 | 13 | 24 |
| 2028 | 19 | 13 | 24 |
| 2029 | 19 | 13 | 24 |
Where the Cliff Swallow Is Detected
BBS routes recording Cliff Swallow, sized by most recent count.
Cliff Swallow Population Trend by State
| Alabama | 173× | 1971 | 66 |
| Alaska | -84% | 1978 | 58 |
| Arizona | -42% | 1970 | 49 |
| Arkansas | 18× | 1976 | 33 |
| California | -14% | 1970 | 215 |
| Colorado | -32% | 1970 | 142 |
| Connecticut | -42% | 1976 | 8 |
| Delaware | insufficient data | n/a | 1 |
| Florida | +7% | 1983 | 7 |
| Georgia | 22× | 1991 | 34 |
| Idaho | +40% | 1970 | 59 |
| Illinois | 179× | 1969 | 95 |
| Indiana | 53× | 1975 | 47 |
| Iowa | 28× | 1970 | 37 |
| Kansas | +152% | 1969 | 65 |
| Kentucky | 77× | 1979 | 29 |
| Louisiana | 38× | 1994 | 62 |
| Maine | -95% | 1968 | 61 |
| Maryland | +32% | 1969 | 20 |
| Massachusetts | -61% | 1969 | 15 |
| Michigan | -66% | 1968 | 82 |
| Minnesota | +292% | 1969 | 82 |
| Mississippi | 41× | 1988 | 44 |
| Missouri | 139× | 1974 | 69 |
| Montana | +43% | 1970 | 103 |
| Nebraska | +112% | 1969 | 70 |
| Nevada | +498% | 1970 | 37 |
| New Hampshire | -93% | 1968 | 22 |
| New Jersey | -48% | 1987 | 5 |
| New Mexico | +148% | 1970 | 71 |
| New York | -80% | 1968 | 92 |
| North Carolina | +108% | 1973 | 25 |
| North Dakota | +203% | 1969 | 51 |
| Ohio | 16× | 1971 | 42 |
| Oklahoma | +308% | 1969 | 61 |
| Oregon | -25% | 1970 | 105 |
| Pennsylvania | -36% | 1968 | 85 |
| South Carolina | +175% | 1990 | 9 |
| South Dakota | +57% | 1969 | 60 |
| Tennessee | 53× | 1968 | 38 |
| Texas | +65% | 1969 | 231 |
| Utah | +16% | 1970 | 88 |
| Vermont | -82% | 1968 | 25 |
| Virginia | +127% | 1969 | 23 |
| Washington | -28% | 1970 | 96 |
| West Virginia | -94% | 1971 | 26 |
| Wisconsin | -21% | 1968 | 94 |
| Wyoming | -27% | 1970 | 124 |
Cliff Swallow Population Trend by Region
Bird Conservation Regions are the ecological unit for trends.
Cliff Swallow Conservation Status
Least Concern
The IUCN Red List rates this species as Least Concern. Our route-weighted index shows it up about 229% 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 2026-05-22. Trend is a route-weighted relative-abundance index, not an absolute population.