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

Eurasian Tree Sparrow Population Trend in Iowa

All statesGeneralists

Eurasian Tree Sparrow in Iowa has surged: up 14× on the route-weighted index since 2013.

14×Since 2013TrendPercent 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 →
8Routes 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 →
13YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Eurasian Tree Sparrow 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 →

long arc increasecomputed 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 →

Eurasian Tree Sparrow has surged in Iowa: up 14× on the route-weighted index since 2013.

Eurasian Tree Sparrow Survey Routes in Iowa

Routes recording Eurasian Tree Sparrow 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 →
West Liberty1820242011
Williamsburg420232019
Mt Hamill320242006
Brooklyn220212014
Mccallsburg220242024
Bryant120232016
Red Rock120242022
Tipton120222022

Eurasian Tree Sparrow Population Trend in Other States

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