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

Tree Swallow In Sierra Nevada

All regionsSierra NevadaAerial insectivores

Tree Swallow in Sierra Nevada has surged: up 94% on the route-weighted index since 1970.

+94%Since 1970
30Routes In Region
56Years

Notable Signals

long arc increasecomputed index

Tree Swallow has surged in Sierra Nevada: up 94% on the route-weighted index since 1970.

Forecast

If the recent trend holds, Tree Swallow in Sierra Nevada is projected to rise about 191% by 2029 — from 1.2 in 2024 to a central estimate of 3.4 (95% range 1.5–5.2). A 5-year backtest shows a typical error of ±93.2%, with 60% of held-out values landing inside the 95% band.

+191%Change by 2029
3.4Projected 2029 index
1.5–5.295% range
±93.2%Backtest error
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 index95% low95% high
20253.21.35.1
20263.31.45.1
20273.31.45.2
20283.31.55.2
20293.41.55.2

Routes In Sierra Nevada

Routes recording Tree Swallow in Sierra Nevada.
Bass LakeCALIFORNIA112018
SattleyCALIFORNIA72014
PaxtonCALIFORNIA72024
KernvilleCALIFORNIA72008
JohnsvilleCALIFORNIA52023
Meadow ValleyCALIFORNIA52024
Last ChanceCALIFORNIA52019
GoumazCALIFORNIA42011
WawonaCALIFORNIA42021
WoodfordsCALIFORNIA32024
GeneseeCALIFORNIA32024
DownievilleCALIFORNIA32024
ChilcootCALIFORNIA31998
Cottage SpgsCALIFORNIA21975
DardanelleCALIFORNIA21993
Greenhorn MtCALIFORNIA22008
Silver CityCALIFORNIA22013
Kings CanyonCALIFORNIA21982
Hat CreekCALIFORNIA22017
Chaos CraterCALIFORNIA22019
CrestviewCALIFORNIA21998
Lassen ParkCALIFORNIA11989
Eagle LakeCALIFORNIA12024
Tuolumne GroveCALIFORNIA12000
Butte MeadowCALIFORNIA12014

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