BirdAnalyst
Species · BCR 33 · BBS 2025 Release · 1966–2024

Lucy's Warbler In Sonoran and Mojave Deserts

All regionsSonoran and Mojave DesertsArid-land birds

Lucy's Warbler in Sonoran and Mojave Deserts has surged: up 159% on the route-weighted index since 1970.

+159%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 →
40Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
55YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable 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 →

Lucy's Warbler has surged in Sonoran and Mojave Deserts: up 159% on the route-weighted index since 1970.

Lucy's Warbler In Sonoran and Mojave Deserts Population Forecast

If the recent trend holds, Lucy's Warbler in Sonoran and Mojave Deserts is projected to rise about 55% by 2029 — from 2.3 in 2024 to a central estimate of 3.5 (95% range 1.5–5.5). A 5-year backtest shows a typical error of ±93.5%, with 60% of held-out values landing inside the 95% band.

+55%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 →
3.5Projected 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 →
1.5–5.595% 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 →
±93.5%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, Lucy's Warbler in Sonoran and Mojave Deserts is projected to rise about 55% by 2029 — from 2.3 in 2024 to a central estimate of 3.5 (95% range 1.5–5.5). A 5-year backtest shows a typical error of ±93.5%, with 60% of held-out values landing inside the 95% band.19682029
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 →
20253.31.35.3
20263.41.35.4
20273.41.45.4
20283.51.55.5
20293.51.55.5

Routes In Sonoran and Mojave Deserts

Routes recording Lucy's Warbler in Sonoran and Mojave Deserts.
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 →
Cutter 2ARIZONA682018
WikieupARIZONA372024
WickenburgARIZONA162023
LukevilleARIZONA131980
New RiverARIZONA122016
Organ PipeARIZONA102023
FlorenceARIZONA91988
Red Rock 2ARIZONA72024
NelsonNEVADA62024
DatelandARIZONA52021
CoolidgeARIZONA51985
RivieraARIZONA52024
Alamo Res.ARIZONA42023
Cibola LakeARIZONA42024
PisinimoARIZONA41993
Red RockARIZONA42014
Squaw PeakARIZONA31968
AjoARIZONA32006
Casa GrandeARIZONA32023
Ajo 2ARIZONA32021
VicksburgARIZONA21980
Palo VerdeARIZONA22013
Cabeza PrietARIZONA22024
Willow BeachARIZONA21995
HopeARIZONA21994

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