Species · BBS 2025 Release · 1966–2024

Bobolink

IcteridaeGrassland birdsDolichonyx oryzivorus

Bobolink has fallen sharply: down 70% on the route-weighted index since 1968.

About the Bobolink

A grassland songbird that makes one of the longest migrations of any American songbird, the Bobolink has declined steeply with the loss of hayfields and prairie.

Size
6–8.5 in long, about 1.3 oz (15–21 cm, 37 g)
Habitat
Open grasslands, prairie, pasture and hayfields.
Diet
Seeds and grain, with insects in the breeding season.
Range
Recorded on 1,278 Breeding Bird Survey routes across 36 states, most concentrated in the Eastern Tallgrass Prairie.
Family
Icteridae · Grassland birds
Conservation
Declining

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

Bobolink has fallen sharply in surveyed states: down 70% on the route-weighted index since 1968.

Bobolink Population Forecast

If the recent trend holds, Bobolink is projected to fall about 34% by 2029 — from 1.3 in 2024 to a central estimate of 0.82 (95% range 0.26–1.4). A 5-year backtest shows a typical error of ±12.6%, with 100% of held-out values landing inside the 95% band.

If the recent trend holds, Bobolink is projected to fall about 34% by 2029 — from 1.3 in 2024 to a central estimate of 0.82 (95% range 0.26–1.4). A 5-year backtest shows a typical error of ±12.6%, 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 →
20251.00.471.6
20260.980.421.5
20270.930.371.5
20280.880.311.4
20290.820.261.4

Where the Bobolink Is Detected

BBS routes recording Bobolink, sized by most recent count.

Bobolink Population Trend by State

Bobolink 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 →
Californiainsufficient datan/a1
Colorado-80%19759
Connecticut-72%196818
Idaho+2%197814
Illinois-97%196860
Indiana-95%196851
Iowa-76%196938
Kansas-71%198210
Kentucky+411%197613
Maine-84%196860
Maryland+509%197016
Massachusetts-44%196826
Michigan-82%196893
Minnesota-34%196980
Missouri+110%196933
Montana+926%197074
Nebraska+144%196958
Nevadainsufficient datan/a1
New Hampshire-63%196825
New Jersey+29%197013
New Mexicoinsufficient datan/a1
New York-36%1968116
North Carolinainsufficient datan/a1
North Dakota+24%196951
Ohio-89%196869
Oregon+47%19779
Pennsylvania-36%1968100
Rhode Islandinsufficient datan/a2
South Dakota+34%196956
Utah-21%20017
Vermont-78%196826
Virginia+87%19924
Washington+11%19906
West Virginia+393%197323
Wisconsin-81%196892
Wyoming+170%197722

Bobolink Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Bobolink 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 →
Great Basin+54%197719
Northern Rockies+134%197053
Prairie Potholes+2%1969120
Boreal Hardwood Transition-48%196899
Lower Great Lakes / St. Lawrence Plain-66%196886
Atlantic Northern Forest-75%1968131
Southern Rockies / Colorado Plateau-84%19755
Badlands and Prairies+190%196996
Shortgrass Prairie+104%198213
Central Mixed Grass Prairie+246%196937
Eastern Tallgrass Prairie-91%1968195
Prairie Hardwood Transition-84%1968155
Central Hardwoods+162%197026
Appalachian Mountains-19%1968176
Piedmont-8%197316
New England / Mid-Atlantic Coast-78%196851

Bobolink Conservation Status

Declining

Long-term surveys document a steep, sustained decline for this species, a recognized conservation concern. Our route-weighted index shows it down about 70% 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.