BirdAnalyst
Species · BBS 2026 Release · 1966–2025

Lucy's Warbler Population Analysis

ParulidaeArid-land birdsLeiothlypis luciae

Lucy's Warbler has risen sharply: up 67% on the route-weighted index since 1970.

+67%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 →
90RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
57Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

About the Lucy's Warbler

The Lucy's Warbler (Leiothlypis luciae) is a North American member of the Wood-Warblers (Parulidae). In this analysis it is grouped with the arid-land birds.

Size
4.5–5.5 in long (11–14 cm) — a small, active songbird (typical for the family)
Habitat
Deserts, dry scrub and brushland of the Southwest.
Diet
Seeds, insects and cactus fruit of arid-land plants.
Range
Recorded on 90 Breeding Bird Survey routes across 6 states, most concentrated in the Sonoran and Mojave Deserts.
Family
Parulidae · Arid-land birds

Notable Lucy's Warbler TrendsNotable 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 risen sharply in surveyed states: up 67% on the route-weighted index since 1970.

Lucy's Warbler Population Forecast

If the recent trend holds, Lucy's Warbler is projected to rise about 17% by 2030 — from 0.20 in 2025 to a central estimate of 0.24 (95% range 0.17–0.31). A 5-year backtest shows a typical error of ±6.8%, with 100% of held-out values landing inside the 95% band.

+17%Change by 2030TrendPercent 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 →
0.24Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.17–0.3195% 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 →
±6.8%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 is projected to rise about 17% by 2030 — from 0.20 in 2025 to a central estimate of 0.24 (95% range 0.17–0.31). A 5-year backtest shows a typical error of ±6.8%, with 100% of held-out values landing inside the 95% band.19682030
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 →
20260.230.160.30
20270.230.160.30
20280.230.160.30
20290.240.170.31
20300.240.170.31

Where the Lucy's Warbler Is Detected

BBS routes recording Lucy's Warbler, sized by most recent count.

Lucy's Warbler Population Trend by State

Lucy's Warbler population trend by state.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Arizona+16%197055
California+101%19803
Nevada+770%19897
New Mexico+358%199312
Texas+64%20016
Utah+505%19947

Lucy's Warbler Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Lucy's Warbler population trend by Bird Conservation Region.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Great Basin+475%19973
Southern Rockies / Colorado Plateau+623%19947
Sonoran and Mojave Deserts+113%197040
Sierra Madre Occidental-43%197024
Chihuahuan Desert+249%199315

Lucy's Warbler Conservation Status

Our route-weighted index shows it up about 67% since 1970.

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14. Trend is a route-weighted relative-abundance index, not an absolute population.