BirdAnalyst
Species · BCR 12 · BBS 2025 Release · 1966–2024

Tree Swallow In Boreal Hardwood Transition

All regionsBoreal Hardwood TransitionAerial insectivores

Tree Swallow in Boreal Hardwood Transition has fallen sharply: down 71% on the route-weighted index since 1968.

-71%Since 1968
122Routes In Region
58Years

Notable Signals

long arc declinecomputed index

Tree Swallow has fallen sharply in Boreal Hardwood Transition: down 71% on the route-weighted index since 1968.

Forecast

If the recent trend holds, Tree Swallow in Boreal Hardwood Transition is projected to fall about 11% by 2029 — from 2.8 in 2024 to a central estimate of 2.5 (95% range 0.00–6.9). A 5-year backtest shows a typical error of ±37.7%, with 100% of held-out values landing inside the 95% band.

-11%Change by 2029
2.5Projected 2029 index
0.00–6.995% range
±37.7%Backtest error
19662029
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
20253.30.007.7
20263.10.007.5
20272.90.007.3
20282.70.007.1
20292.50.006.9

Routes In Boreal Hardwood Transition

Routes recording Tree Swallow in Boreal Hardwood Transition.
HerronMICHIGAN402016
BagleyMINNESOTA272006
FredericMICHIGAN232003
CathroMICHIGAN172016
CunardMICHIGAN162021
Pleasant ValMICHIGAN161997
PickfordMICHIGAN152024
BrainerdMINNESOTA152024
Iron RiverWISCONSIN152024
BayfieldWISCONSIN152024
Cedar RunMICHIGAN141999
Lake CityMICHIGAN132022
BackusMINNESOTA132024
DebsMINNESOTA122023
LudeMINNESOTA122023
FlambeauWISCONSIN112024
BootjackMICHIGAN102023
RiggsvilleMICHIGAN102019
SkeelsMICHIGAN102015
Wigwam BayMINNESOTA102023
CouderayWISCONSIN102019
PhillipsWISCONSIN102024
Beaver LakeMICHIGAN82011
Frederic 2MICHIGAN82017
Island LakeMINNESOTA81995

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