BirdAnalyst
Species · Maryland · BBS 2025 Release · 1966–2024

Henslow's Sparrow Population Trend in Maryland

All statesGrassland birds

Henslow's Sparrow in Maryland has fallen sharply: down 66% on the route-weighted index since 1969.

-66%Since 1969TrendPercent 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 →
12Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
14YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Henslow's Sparrow Trends in MarylandNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

long arc declinecomputed 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 →

Henslow's Sparrow has fallen sharply in Maryland: down 65% on the route-weighted index since 1969.

Henslow's Sparrow Survey Routes in Maryland

Routes recording Henslow's Sparrow in Maryland.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →
Madison219691968
Newark219701969
Theodore119681968
Piney Neck119711971
Accident119941994
Emmitsburg119691969
Olney119721972
Warfieldsbrg119691969
Cokesbury119671967
Fowblesburg119691969
Finzel120211999
Cheltenham119981998

Henslow's Sparrow Population Trend in Other States

delawareillinoisindianaiowakansaskentuckymichiganminnesotamissourinebraskanew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniasouth-dakotavermontvirginiawest-virginiawisconsin

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