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

Great-tailed Grackle Population Trend in Iowa

All statesGeneralists

Great-tailed Grackle in Iowa has edged down: down 24% on the route-weighted index since 1999.

-24%Since 1999TrendPercent 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 →
6Routes 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 →
17YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Great-tailed Grackle Trends in IowaNotable 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 Great-tailed Grackle in Iowa. See the full index history below.

Great-tailed Grackle Survey Routes in Iowa

Routes recording Great-tailed Grackle in Iowa.
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 →
Scranton719961994
Wales520132007
Neola220112011
Hudson220222021
Sioux City220141999
Bedford120182013

Great-tailed Grackle Population Trend in Other States

arizonaarkansascaliforniacoloradoidahoillinoiskansaslouisianamissourinebraskanevadanew-mexicooklahomaoregonsouth-dakotatexasutahwyoming

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