BirdAnalyst
Species · BCR 35 · BBS 2025 Release · 1966–2024

Bronzed Cowbird In Chihuahuan Desert

All regionsChihuahuan DesertGeneralists

Bronzed Cowbird in Chihuahuan Desert has fallen sharply: down 52% on the route-weighted index since 1983.

-52%Since 1983TrendPercent 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 →
29Routes 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 →
38YearsYears 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 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 →

Bronzed Cowbird has fallen sharply in Chihuahuan Desert: down 52% on the route-weighted index since 1983.

Bronzed Cowbird In Chihuahuan Desert Population Forecast

If the recent trend holds, Bronzed Cowbird in Chihuahuan Desert is projected to stay roughly flat through 2029, near 0.18 (95% range 0.00–0.77). A 5-year backtest shows a typical error of ±199.8%, with 100% of held-out values landing inside the 95% band.

+3%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 →
0.18Projected 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 →
0.00–0.7795% 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 →
±199.8%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, Bronzed Cowbird in Chihuahuan Desert is projected to stay roughly flat through 2029, near 0.18 (95% range 0.00–0.77). A 5-year backtest shows a typical error of ±199.8%, with 100% of held-out values landing inside the 95% band.19772029
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 →
20250.200.000.79
20260.190.000.78
20270.190.000.78
20280.180.000.77
20290.180.000.77

Routes In Chihuahuan Desert

Routes recording Bronzed Cowbird in Chihuahuan Desert.
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 →
ComstockTEXAS62017
ShafterTEXAS61985
PumpvilleTEXAS62011
ToyahvaleTEXAS52005
GirvinTEXAS32017
MarathonTEXAS32011
Van HornTEXAS32024
GageNEW-MEXICO22012
ColumbusNEW-MEXICO22013
Black GapTEXAS22013
LongfellowTEXAS22022
OzonaTEXAS22018
Bear MtnTEXAS21989
Devils R CynTEXAS22017
JornadaNEW-MEXICO12014
RodeoNEW-MEXICO12021
Bitter LakeNEW-MEXICO12016
Hatchet PeakNEW-MEXICO12007
Hot SpringsTEXAS11992
AltudaTEXAS12004
ValentineTEXAS11987
Casa PiedraTEXAS12015
CastolonTEXAS11998
PresidioTEXAS12015
Coyanda DrawTEXAS12024

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