BirdAnalyst
Species · BBS 2026 Release · 1966–2025

Hermit Thrush Population Analysis

TurdidaeForest birdsCatharus guttatus

Hermit Thrush has surged: up 218% on the route-weighted index since 1968.

+218%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 →
1,225RoutesSurvey 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 Hermit Thrush

The Hermit Thrush (Catharus guttatus) is a North American member of the Thrushes (Turdidae). In this analysis it is grouped with the forest birds.

Size
6–11 in long (15–28 cm) — a medium songbird (typical for the family)
Habitat
Woodlands and forest edges, including wooded suburbs and parks.
Diet
Insects and spiders gleaned from foliage and bark, with seeds and berries in season.
Range
Recorded on 1,225 Breeding Bird Survey routes across 33 states, most concentrated in the Atlantic Northern Forest.
Family
Turdidae · Forest birds

Notable Hermit Thrush 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 →

Hermit Thrush has surged in surveyed states: up 218% on the route-weighted index since 1968.

Hermit Thrush Population Forecast

If the recent trend holds, Hermit Thrush is projected to rise about 68% by 2030 — from 1.5 in 2025 to a central estimate of 2.6 (95% range 1.8–3.4). A 5-year backtest shows a typical error of ±66.8%, with 0% of held-out values landing inside the 95% band.

+68%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 →
2.6Projected 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 →
1.8–3.495% 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 →
±66.8%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, Hermit Thrush is projected to rise about 68% by 2030 — from 1.5 in 2025 to a central estimate of 2.6 (95% range 1.8–3.4). A 5-year backtest shows a typical error of ±66.8%, with 0% 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 →
20262.41.63.2
20272.51.73.3
20282.51.73.3
20292.51.73.3
20302.61.83.4

Where the Hermit Thrush Is Detected

BBS routes recording Hermit Thrush, sized by most recent count.

Hermit Thrush Population Trend by State

Hermit Thrush 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 →
Alaska+142%1972107
Arizona+417%197023
California+21%1970116
Colorado+247%197082
Connecticut-48%196917
Idaho+103%197138
Indianainsufficient datan/a1
Maine-24%196878
Maryland+746%19779
Massachusetts+5%196830
Michigan+79%196868
Minnesota+76%196941
Montana+738%197339
Nevada-82%19997
New Hampshire+52%196826
New Jersey-33%19804
New Mexico+621%197123
New York+30%1968101
North Carolinainsufficient datan/a3
Ohio-23%19945
Oregon-28%197086
Pennsylvania+167%196881
Rhode Island-30%19735
South Dakotainsufficient datan/a1
Tennesseeinsufficient datan/a1
Texasinsufficient datan/a2
Utah+20%197043
Vermont-5%196826
Virginiainsufficient datan/a5
Washington+152%197051
West Virginia21×197920
Wisconsin+111%196850
Wyoming+760%197636

Hermit Thrush Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Hermit Thrush 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 →
BCR 2-54%198512
BCR 4+62%197659
Northern Pacific Rainforest+171%1970123
Great Basin-10%197085
Northern Rockies+239%1970127
Boreal Hardwood Transition+66%1968124
Lower Great Lakes / St. Lawrence Plain-27%196851
Atlantic Northern Forest+23%1968156
Sierra Nevada-49%197236
Southern Rockies / Colorado Plateau+274%1970142
Badlands and Prairies+405%19978
Prairie Hardwood Transition+357%196832
Appalachian Mountains+269%1968150
New England / Mid-Atlantic Coast-41%196853
Coastal California+186%197328
Sierra Madre Occidental+28%197023
Chihuahuan Desert-59%19786

Hermit Thrush Conservation Status

Our route-weighted index shows it up about 218% since 1968.

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