BirdAnalyst
Species · BBS 2025 Release · 1966–2024

Vesper Sparrow

PasserellidaeGrassland birdsPooecetes gramineus

Vesper Sparrow has held roughly steady: up 2% on the route-weighted index since 1968.

+2%Since 1968TrendPercent 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 →
1,929RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
58Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

About the Vesper Sparrow

The Vesper Sparrow (Pooecetes gramineus) is a North American member of the New World Sparrows (Passerellidae). In this analysis it is grouped with the grassland birds.

Size
4.5–7.5 in long (12–19 cm) — a small songbird (typical for the family)
Habitat
Open grasslands, prairie, pasture and hayfields.
Diet
Seeds and insects gathered from grasses and the ground.
Range
Recorded on 1,929 Breeding Bird Survey routes across 40 states, most concentrated in the Eastern Tallgrass Prairie.
Family
Passerellidae · Grassland birds

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

No notable trend signals for Vesper Sparrow. See the full index history below.

Vesper Sparrow Population Forecast

If the recent trend holds, Vesper Sparrow is projected to stay roughly flat through 2029, near 3.6 (95% range 2.6–4.7). A 5-year backtest shows a typical error of ±13%, with 100% of held-out values landing inside the 95% band.

-5%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 →
3.6Projected 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 →
2.6–4.795% 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 →
±13%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, Vesper Sparrow is projected to stay roughly flat through 2029, near 3.6 (95% range 2.6–4.7). A 5-year backtest shows a typical error of ±13%, 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 →
20253.62.54.7
20263.62.54.7
20273.62.54.7
20283.62.54.7
20293.62.64.7

Where the Vesper Sparrow Is Detected

BBS routes recording Vesper Sparrow, sized by most recent count.

Vesper Sparrow Population Trend by State

Vesper Sparrow population trend by state.
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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Arizona-43%197025
California+638%197241
Colorado19×1970124
Connecticutinsufficient datan/a1
Delaware-81%196814
Idaho+323%197050
Illinois-44%196886
Indiana-88%196858
Iowa-65%196938
Kansas-20%197515
Kentuckyinsufficient datan/a7
Maine-99%196831
Maryland-98%196850
Massachusetts-79%19689
Michigan-92%196898
Minnesota-48%196970
Missouri-73%197123
Montana+70%1970105
Nebraska+119%197050
Nevada+202%197135
New Hampshire-86%196820
New Jersey-67%196811
New Mexico+437%197342
New York-87%196893
North Carolinainsufficient datan/a4
North Dakota+27%196951
Ohio-89%196873
Oklahomainsufficient datan/a1
Oregon+89%197085
Pennsylvania-96%1968104
South Dakota-25%196962
Tennesseeinsufficient datan/a1
Texasinsufficient datan/a5
Utah+3%197094
Vermont-88%196918
Virginia-96%196826
Washington+112%197057
West Virginia-96%196824
Wisconsin-93%196890
Wyoming+34%1970138

Vesper Sparrow Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Vesper Sparrow population trend by Bird Conservation Region.
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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Northern Pacific Rainforest-93%197023
Great Basin+172%1970212
Northern Rockies+61%1970188
Prairie Potholes+31%1969123
Boreal Hardwood Transition-79%196897
Lower Great Lakes / St. Lawrence Plain-86%196878
Atlantic Northern Forest-97%196877
Sierra Nevada+2%197311
Southern Rockies / Colorado Plateau+94%1970201
Badlands and Prairies+135%1969137
Shortgrass Prairie+526%197056
Central Mixed Grass Prairie+57%197027
Eastern Tallgrass Prairie-73%1968215
Prairie Hardwood Transition-91%1968149
Central Hardwoods-83%196828
Appalachian Mountains-97%1968190
Piedmont-99%196834
New England / Mid-Atlantic Coast-97%196861
Sierra Madre Occidental-45%197011
Chihuahuan Desert-93%19803

Vesper Sparrow Conservation Status

Our route-weighted index shows it up about 2% since 1968. Grassland birds are North America's steepest-declining group, down roughly 50% since 1970 as prairie and pasture were lost.

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22. Trend is a route-weighted relative-abundance index, not an absolute population.