BirdAnalyst
Species · BCR 9 · BBS 2026 Release · 1966–2025

Tree Swallow In Great Basin

All regionsGreat BasinAerial insectivores

Tree Swallow in Great Basin has risen sharply: up 63% on the route-weighted index since 1970.

+63%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 →
170Routes 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 →
57YearsYears 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 →

Tree Swallow has risen sharply in Great Basin: up 63% on the route-weighted index since 1970.

Tree Swallow In Great Basin Population Forecast

If the recent trend holds, Tree Swallow in Great Basin is projected to rise about 29% by 2030 — from 1.8 in 2025 to a central estimate of 2.4 (95% range 0.95–3.8). A 5-year backtest shows a typical error of ±66.7%, with 80% of held-out values landing inside the 95% band.

+29%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 →
2.4Projected 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 →
0.95–3.895% 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 →
±66.7%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, Tree Swallow in Great Basin is projected to rise about 29% by 2030 — from 1.8 in 2025 to a central estimate of 2.4 (95% range 0.95–3.8). A 5-year backtest shows a typical error of ±66.7%, with 80% 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 →
20262.30.943.8
20272.30.943.8
20282.40.943.8
20292.40.943.8
20302.40.953.8

Routes In Great Basin

Routes recording Tree Swallow in Great Basin.
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 →
HenryIDAHO931983
FallonNEVADA821998
Modoc PointOREGON552018
Modoc Point 2OREGON532025
TwispWASHINGTON302024
RavendaleCALIFORNIA262025
HarringtonWASHINGTON252012
Dinner StaNEVADA201968
Ruby ValleyNEVADA192000
Barnes ValOREGON191987
Daniels ResIDAHO152007
OrdnanceOREGON141979
WapatoWASHINGTON132019
EllensburgWASHINGTON132025
Magic MtnIDAHO122025
AdrianOREGON122025
LikelyCALIFORNIA102025
HackamoreCALIFORNIA92010
LeavenworthWASHINGTON92024
MacdoelCALIFORNIA82019
Iron GateCALIFORNIA82019
Oak CityUTAH82016
Hardware RanchUTAH82016
AsotinWASHINGTON82025
Majors PlaceNEVADA72012

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.