BirdAnalyst
Guild · Vermont · BBS 2025 Release · 1966–2024

Aerial Insectivores In Vermont

All statesVermont

16 species in this guild. As a group they are -56%Guild trendA mean-index aggregate across the species in this group — the structural direction of the guild, with individual-species noise smoothed out.Full methodology → since 1968.

Guild SignalsNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

guild collapsecomputed 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 →

Aerial insectivores as a group have fallen sharply in Vermont, down 56% since 1968.

Aerial Insectivores In Vermont Population Forecast

If the recent trend holds, Aerial insectivores in Vermont is projected to fall about 47% by 2029 — from 2.7 in 2024 to a central estimate of 1.4 (95% range 0.22–2.7). A 5-year backtest shows a typical error of ±22%, with 100% of held-out values landing inside the 95% band.

-47%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 →
1.4Projected 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 →
0.22–2.795% 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 →
±22%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, Aerial insectivores in Vermont is projected to fall about 47% by 2029 — from 2.7 in 2024 to a central estimate of 1.4 (95% range 0.22–2.7). A 5-year backtest shows a typical error of ±22%, with 100% of held-out values landing inside the 95% band.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 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 →
20251.80.563.0
20261.70.472.9
20271.60.392.8
20281.50.302.8
20291.40.222.7

Member Species In Vermont

Aerial insectivores species in Vermont.
TrendPercent 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 →
Bank SwallowHirundinidae-93%
Cliff SwallowHirundinidae-82%
Eastern KingbirdTyrannidae-79%
Barn SwallowHirundinidae-79%
Chimney SwiftApodidae-77%
Olive-sided FlycatcherTyrannidae-75%
Tree SwallowHirundinidae-72%
Purple MartinHirundinidae-71%
Yellow-bellied FlycatcherTyrannidae-62%
Least FlycatcherTyrannidae-46%
Great Crested FlycatcherTyrannidae-37%
Eastern Wood-PeweeTyrannidae-17%
Eastern PhoebeTyrannidae-16%
Northern Rough-winged SwallowHirundinidae+34%
Willow FlycatcherTyrannidae+100%
Alder FlycatcherTyrannidae+242%

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