Species · Connecticut · BBS 2025 Release · 1966–2024
Northern Rough-winged Swallow Population Trend in Connecticut
Northern Rough-winged Swallow in Connecticut has surged: up 295% on the route-weighted index since 1969.
+295%Since 1969
18Routes In State
53Years
Notable Northern Rough-winged Swallow Trends in Connecticut
long arc increasecomputed index
Northern Rough-winged Swallow has surged in Connecticut: up 295% on the route-weighted index since 1969.
Northern Rough-winged Swallow Population Forecast in Connecticut
If the recent trend holds, Northern Rough-winged Swallow in Connecticut is projected to fall about 24% by 2029 — from 2.3 in 2024 to a central estimate of 1.8 (95% range 0.09–3.4). A 5-year backtest shows a typical error of ±77.8%, with 100% of held-out values landing inside the 95% band.
-24%Change by 2029
1.8Projected 2029 index
0.09–3.495% range
±77.8%Backtest error
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 1.7 | 0.01 | 3.4 |
| 2026 | 1.7 | 0.03 | 3.4 |
| 2027 | 1.7 | 0.05 | 3.4 |
| 2028 | 1.7 | 0.07 | 3.4 |
| 2029 | 1.8 | 0.09 | 3.4 |
Northern Rough-winged Swallow Survey Routes in Connecticut
| Uncasville | 15 | 2024 | 1982 |
| Buckingham | 5 | 2022 | 1981 |
| Danbury | 5 | 2017 | 1976 |
| Sherman | 4 | 2019 | 1974 |
| Mystic | 3 | 2013 | 1977 |
| New Hartford | 3 | 2006 | 1994 |
| Mid Haddam | 3 | 2024 | 1975 |
| Westbrook | 2 | 2024 | 1974 |
| Southington | 2 | 2017 | 1995 |
| Warren 2 | 2 | 2022 | 2022 |
| E Hartland | 1 | 1992 | 1968 |
| Willimantic | 1 | 2014 | 1967 |
| No Woodbury | 1 | 2010 | 1980 |
| Greenwich | 1 | 2008 | 1974 |
| Warren | 1 | 2009 | 1977 |
| Long Hill | 1 | 2018 | 1977 |
| New Hartford | 1 | 1987 | 1973 |
| Granby | 1 | 2024 | 1990 |
Northern Rough-winged Swallow Population Trend in Other States
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Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.