BirdAnalyst
Species · BBS 2025 Release · 1966–2024

Carolina Wren

TroglodytidaeForest birdsThryothorus ludovicianus

Carolina Wren has surged: up 109% on the route-weighted index since 1968.

+109%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 →
2,082RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
58Years 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 Carolina Wren

A rich-rust, loud-voiced wren of southeastern thickets and yards, the Carolina Wren sings a ringing 'teakettle' song all year.

Size
4.5–5.5 in long, about 0.7 oz (12–14 cm, 20 g)
Habitat
Woodlands and forest edges, including wooded suburbs and parks.
Diet
Insects and spiders gleaned from low cover, with some seeds and fruit.
Range
Recorded on 2,082 Breeding Bird Survey routes across 35 states, most concentrated in the Appalachian Mountains.
Family
Troglodytidae · Forest birds
Conservation
Least Concern

Notable Carolina Wren 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 →

Carolina Wren has surged in surveyed states: up 109% on the route-weighted index since 1968.

Carolina Wren Population Forecast

If the recent trend holds, Carolina Wren is projected to stay roughly flat through 2029, near 8.8 (95% range 7.1–11). A 5-year backtest shows a typical error of ±10.3%, with 100% of held-out values landing inside the 95% band.

-8%Change by 2029TrendPercent 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 →
8.8Projected 2029 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
7.1–1195% 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 →
±10.3%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, Carolina Wren is projected to stay roughly flat through 2029, near 8.8 (95% range 7.1–11). A 5-year backtest shows a typical error of ±10.3%, with 100% of held-out values landing inside the 95% band.19662029
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 →
20258.46.710
20268.56.810
20278.66.910
20288.77.010
20298.87.111

Where the Carolina Wren Is Detected

BBS routes recording Carolina Wren, sized by most recent count.

Carolina Wren Population Trend by State

Carolina Wren 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+99%1968109
Arkansas+18%196962
Connecticut33×197620
Delaware13×196817
Florida+68%1968124
Georgia+137%1968111
Illinois+196%196886
Indiana+85%196864
Iowa+220%197110
Kansas+574%196947
Kentucky+132%196864
Louisiana+172%196997
Maine15×20009
Maryland11×196876
Massachusetts67×197127
Michigan+756%198729
Minnesotainsufficient datan/a3
Mississippi+325%196874
Missouri+99%196991
Nebraska-15%197611
New Hampshire20×200313
New Jersey54×196842
New York101×197176
North Carolina+171%1968111
Ohio+374%196888
Oklahoma+139%196962
Pennsylvania32×1968131
Rhode Island24×19757
South Carolina+8%196851
Tennessee+183%196855
Texas+148%1969150
Vermont+299%19948
Virginia+581%196888
West Virginia+296%196863
Wisconsininsufficient datan/a6

Carolina Wren Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Carolina Wren 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 →
Lower Great Lakes / St. Lawrence Plain62×196964
Atlantic Northern Forest27×197632
Central Mixed Grass Prairie20×196966
Edwards Plateau+183%196919
Oaks and Prairies+530%196974
Eastern Tallgrass Prairie+129%1968227
Prairie Hardwood Transition22×197351
Central Hardwoods+87%1968166
West Gulf Coastal Plain / Ouachitas+81%1969110
Mississippi Alluvial Valley+368%196873
Southeastern Coastal Plain+147%1968346
Appalachian Mountains+219%1968389
Piedmont+416%1968170
New England / Mid-Atlantic Coast+928%1968160
Peninsular Florida+18%196879
Tamaulipan Brushlands+70%197610
Gulf Coastal Prairie+4%196941

Carolina Wren Conservation Status

Least Concern

The IUCN Red List rates this species as Least Concern. Our route-weighted index shows it up about 109% since 1968.

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22. Trend is a route-weighted relative-abundance index, not an absolute population.