BirdAnalyst
Species · BCR 15 · BBS 2025 Release · 1966–2024

Wrentit In Sierra Nevada

All regionsSierra NevadaGeneralists

Wrentit in Sierra Nevada has fallen sharply: down 53% on the route-weighted index since 1972.

-53%Since 1972TrendPercent 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 →
54YearsYears 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 →

Wrentit has fallen sharply in Sierra Nevada: down 53% on the route-weighted index since 1972.

Forecast

If the recent trend holds, Wrentit in Sierra Nevada is projected to rise about 248% by 2029 — from 0.90 in 2024 to a central estimate of 3.1 (95% range 0.64–5.6). A 5-year backtest shows a typical error of ±123.7%, with 60% of held-out values landing inside the 95% band.

+248%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 →
3.1Projected 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 →
0.64–5.695% 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 →
±123.7%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, Wrentit in Sierra Nevada is projected to rise about 248% by 2029 — from 0.90 in 2024 to a central estimate of 3.1 (95% range 0.64–5.6). A 5-year backtest shows a typical error of ±123.7%, 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 →
20253.10.625.6
20263.10.635.6
20273.10.635.6
20283.10.635.6
20293.10.645.6

Routes In Sierra Nevada

Routes recording Wrentit in Sierra Nevada.
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 →
Forest HillCALIFORNIA342022
Silver CityCALIFORNIA332013
CoultervilleCALIFORNIA302019
Forest Hill 2CALIFORNIA202005
WawonaCALIFORNIA72024
Kings CanyonCALIFORNIA62024
RivertonCALIFORNIA62018
Cottage SpgsCALIFORNIA51975
Higgins CornCALIFORNIA42024
LakeshoreCALIFORNIA32014
StrawberryCALIFORNIA32015
Bass LakeCALIFORNIA22019
JohnsvilleCALIFORNIA21992
Hat CreekCALIFORNIA22012
Tahoe NfCALIFORNIA21994
Lassen ParkCALIFORNIA11988
WestvilleCALIFORNIA12023
Greenhorn MtCALIFORNIA11993
Tuolumne GroveCALIFORNIA12023
SattleyCALIFORNIA11973
GeneseeCALIFORNIA11983
DownievilleCALIFORNIA12009
Chaos CraterCALIFORNIA12014
PaxtonCALIFORNIA12019
PlacervilleCALIFORNIA12022

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