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

Black-headed Grosbeak In Chihuahuan Desert

All regionsChihuahuan DesertGeneralists

Black-headed Grosbeak in Chihuahuan Desert has surged: up 123% on the route-weighted index since 1970.

+123%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 →
26Routes 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 →
56YearsYears 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 →

Black-headed Grosbeak has surged in Chihuahuan Desert: up 123% on the route-weighted index since 1970.

Black-headed Grosbeak In Chihuahuan Desert Population Forecast

If the recent trend holds, Black-headed Grosbeak in Chihuahuan Desert is projected to fall about 24% by 2029 — from 2.5 in 2024 to a central estimate of 1.9 (95% range 0.67–3.2). A 5-year backtest shows a typical error of ±25.9%, with 100% of held-out values landing inside the 95% band.

-24%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 →
1.9Projected 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 →
0.67–3.295% 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 →
±25.9%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, Black-headed Grosbeak in Chihuahuan Desert is projected to fall about 24% by 2029 — from 2.5 in 2024 to a central estimate of 1.9 (95% range 0.67–3.2). A 5-year backtest shows a typical error of ±25.9%, with 100% 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 →
20251.80.593.1
20261.90.613.1
20271.90.633.1
20281.90.653.2
20291.90.673.2

Routes In Chihuahuan Desert

Routes recording Black-headed Grosbeak 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 →
CloudcroftNEW-MEXICO552024
Capitan Mtn.NEW-MEXICO52017
PinonNEW-MEXICO52024
MesillaNEW-MEXICO42000
CarrizozoNEW-MEXICO32024
LaborcitaNEW-MEXICO32018
Sunshine WllNEW-MEXICO32024
ValentineTEXAS31987
Bear MtnTEXAS32024
DemingNEW-MEXICO21974
JornadaNEW-MEXICO22007
Laborcita 2NEW-MEXICO22024
Salt FlatTEXAS22006
Chisos BasinTEXAS22023
San AntonioNEW-MEXICO11974
RoswellNEW-MEXICO11975
GageNEW-MEXICO11969
RodeoNEW-MEXICO12022
Red RockNEW-MEXICO12024
QueenNEW-MEXICO12018
EscondidaNEW-MEXICO12016
Hot SpringsTEXAS11997
LongfellowTEXAS12022
ToyahvaleTEXAS12024
Sierra BlancTEXAS12002

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