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Species · Michigan · BBS 2025 Release · 1966–2024

Black-throated Green Warbler Population Trend in Michigan

All statesForest birds

Black-throated Green Warbler in Michigan has surged: up 470% on the route-weighted index since 1968.

+470%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 →
70Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
58YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Black-throated Green Warbler Trends in MichiganNotable 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 →

Black-throated Green Warbler has surged in Michigan: up 470% on the route-weighted index since 1968.

Black-throated Green Warbler Population Forecast in Michigan

If the recent trend holds, Black-throated Green Warbler in Michigan is projected to rise about 89% by 2029 — from 2.5 in 2024 to a central estimate of 4.8 (95% range 3.0–6.6). A 5-year backtest shows a typical error of ±65.7%, with 20% of held-out values landing inside the 95% band.

+89%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 →
4.8Projected 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 →
3.0–6.695% 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 →
±65.7%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, Black-throated Green Warbler in Michigan is projected to rise about 89% by 2029 — from 2.5 in 2024 to a central estimate of 4.8 (95% range 3.0–6.6). A 5-year backtest shows a typical error of ±65.7%, with 20% 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 →
20254.52.76.3
20264.62.86.4
20274.62.96.4
20284.72.96.5
20294.83.06.6

Black-throated Green Warbler Survey Routes in Michigan

Routes recording Black-throated Green Warbler in Michigan.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →
Imp Lake2420191992
Ensign2220102006
Scott'S Marsh1620102006
Big Island Lake1620102008
Hiawatha Nf1520241992
Sidnaw1520241993
Marenisco1420191981
Gooseneck1420102008
Gilchrist1220211974
Cluster Lakes1220102006
Isabella 21220242013
Ontonagon1020191970
Muskallonge1020241968
Betchler Lks1020241992
Herman920221983
Gibbs City820241979
Shingleton820241967
Raco820241971
Tahquamenon720241974
Bergland520221982
Ned Lake520241986
Isabella520121966
Pickford520241973
Brush Creek520161974
Maple Grove420241969

Black-throated Green Warbler Population Trend in Other States

alabamaarkansasconnecticutgeorgiaindianakentuckymainemarylandmassachusettsminnesotamissourinew-hampshirenew-jerseynew-yorknorth-carolinaohiooklahomapennsylvaniarhode-islandsouth-carolinatennesseevermontvirginiawest-virginiawisconsin

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.