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

Ruby-throated Hummingbird Population Trend in Iowa

All statesGeneralists

Ruby-throated Hummingbird in Iowa has surged: up 391% on the route-weighted index since 1970.

+391%Since 1970TrendPercent 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 →
21Routes 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 →
42YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Ruby-throated Hummingbird Trends in IowaNotable 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 →

Ruby-throated Hummingbird has surged in Iowa: up 391% on the route-weighted index since 1970.

Ruby-throated Hummingbird Population Forecast in Iowa

If the recent trend holds, Ruby-throated Hummingbird in Iowa is projected to rise about 51% by 2029 — from 0.18 in 2024 to a central estimate of 0.28 (95% range 0.08–0.47). A 5-year backtest shows a typical error of ±48.2%, with 80% of held-out values landing inside the 95% band.

+51%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 →
0.28Projected 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 →
0.08–0.4795% 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 →
±48.2%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, Ruby-throated Hummingbird in Iowa is projected to rise about 51% by 2029 — from 0.18 in 2024 to a central estimate of 0.28 (95% range 0.08–0.47). A 5-year backtest shows a typical error of ±48.2%, with 80% of held-out values landing inside the 95% band.19672029
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 →
20250.260.060.46
20260.260.060.46
20270.270.070.47
20280.270.070.47
20290.280.080.47

Ruby-throated Hummingbird Survey Routes in Iowa

Routes recording Ruby-throated Hummingbird in Iowa.
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 →
West Liberty219891986
Maquoketa220191969
Washta220141998
Gaza220041998
Mt Hamill120241977
Exline120232000
Melrose120242019
Bryant120232013
Brooklyn120152006
Williamsburg119801980
Red Rock120241988
Wales120162016
Alice119991991
Prairieburg119671967
Hudson120222022
Zearing119951995
Sioux City120171970
Festina120221973
Tipton120142014
Lafayette120232003
Mccallsburg120242024

Ruby-throated Hummingbird Population Trend in Other States

alabamaarkansasconnecticutdelawarefloridageorgiaillinoisindianakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourinebraskanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawest-virginiawisconsin

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