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Species · Alaska · BBS 2025 Release · 1966–2024

MacGillivray's Warbler Population Trend in Alaska

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MacGillivray's Warbler in Alaska has collapsed: down 92% on the route-weighted index since 1986.

-92%Since 1986TrendPercent 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 →
16Routes 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 →
37YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable MacGillivray's Warbler Trends in AlaskaNotable 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 →

MacGillivray's Warbler has collapsed in Alaska: down 92% on the route-weighted index since 1986.

MacGillivray's Warbler Population Forecast in Alaska

If the recent trend holds, MacGillivray's Warbler in Alaska is projected to fall about 100% by 2029 — from 0.07 in 2024 to a central estimate of 0.00 (95% range 0.00–0.46). A 5-year backtest shows a typical error of ±170.6%, with 100% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–0.4695% 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 →
±170.6%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, MacGillivray's Warbler in Alaska is projected to fall about 100% by 2029 — from 0.07 in 2024 to a central estimate of 0.00 (95% range 0.00–0.46). A 5-year backtest shows a typical error of ±170.6%, with 100% of held-out values landing inside the 95% band.19722029
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 →
20250.000.000.46
20260.000.000.46
20270.000.000.46
20280.000.000.46
20290.000.000.46

MacGillivray's Warbler Survey Routes in Alaska

Routes recording MacGillivray's Warbler in Alaska.
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 →
Hyder1020091994
Craig320191987
Thorne Bay319901990
Stikine River220241998
Kuiu Island220042004
Juneau Alt219861986
Haines220241972
Zimovia Strt119941988
Eagle119821982
Skagway120141993
Zarembo119931993
Juneau119861986
Ketchikan120162000
Whale Pass120192019
Yakutat120042004
Mitkof Isle120241989

MacGillivray's Warbler Population Trend in Other States

arizonacaliforniacoloradoidahomontananevadanew-mexicooregonsouth-dakotatexasutahwashingtonwyoming

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