BirdAnalyst
Species · Michigan · BBS 2025 Release · 1966–2024

Willow Flycatcher Population Trend in Michigan

All statesAerial insectivores

Willow Flycatcher in Michigan has fallen sharply: down 61% on the route-weighted index since 1968.

-61%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 Willow Flycatcher 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 declinecomputed 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 →

Willow Flycatcher has fallen sharply in Michigan: down 61% on the route-weighted index since 1968.

Willow Flycatcher Population Forecast in Michigan

If the recent trend holds, Willow Flycatcher in Michigan is projected to rise about 35% by 2029 — from 0.68 in 2024 to a central estimate of 0.92 (95% range 0.16–1.7). A 5-year backtest shows a typical error of ±34.7%, with 100% of held-out values landing inside the 95% band.

+35%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 →
0.92Projected 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 →
0.16–1.795% 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 →
±34.7%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, Willow Flycatcher in Michigan is projected to rise about 35% by 2029 — from 0.68 in 2024 to a central estimate of 0.92 (95% range 0.16–1.7). A 5-year backtest shows a typical error of ±34.7%, 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 →
20251.000.241.8
20260.980.221.7
20270.960.201.7
20280.940.181.7
20290.920.161.7

Willow Flycatcher Survey Routes in Michigan

Routes recording Willow Flycatcher 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 →
Hamburg 2620232006
Drayton Plns619871975
Tyre619961967
Hamburg620011981
Lawrence520241969
Howardsville520241969
Barry S.G.A. 2420182014
Skegemog Pt419871977
Galesburg420241967
Pettysville419791969
Marenisco320122006
New Buffalo320141992
Seney Nwr319941993
New Troy320231971
Coopersville320241985
Lapeer320232001
Frederic320011997
Holt320241969
Prattville320211967
Cathro319891987
Juniata320231966
North Branch319991982
S Lyons319891966
Deckerville320241978
Big Blue Lk219871987

Willow Flycatcher Population Trend in Other States

alaskaarizonaarkansascaliforniacoloradoconnecticutdelawaregeorgiaidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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