Orange-crowned Warblers mostly pass through Iowa: they arrive in mid September, peak in early October (11% of checklists), and most are gone by late October.
When to look
First arrivalsSep 15-21mid September
Common bySep 15-21mid September
PeakOct 1-7early October
Most gone byOct 22-31late October
Best: early October. First arrivals mid September; most are gone by late October. Peak: on about 11% of Iowa checklists.
Jannot usually seen
Febnot usually seen
Marnot usually seen
Aprcommon
Maycommon
Junnot usually seen
Julnot usually seen
Augnot usually seen
Sepcommon
Octpeak season
Novrare
Decnot usually seen
Darker months: more checklists report it. Outlined: peak month.
Share of complete checklists reporting it, by week (4 per month). Grey bars: fewer than 10 checklists, not counted.
Frequency is the share of complete checklists in Iowa that listed the bird, 2016–2025. It is not a head count, and it follows where and when people go birding. How to read it.
JanFebMarAprMayJunJulAugSepOctNovDec
today
0%few checklistsno data
Each county is shaded by the share of complete checklists there that listed the bird, blended with the weeks either side. Darker is more often. It follows where people watch birds, not how many birds there are. How to read it.
Robison Wildlife AcresStory County, best the second week of May · 23 checklists that week, 203 in all37%
Waterworks ParkPolk County, best early May · 37 checklists that week, 1,058 in all36%
Reactor WoodsStory County, best early May · 44 checklists that week, 397 in all35%
Busy spots report more of everything; compare the checklist counts before you drive anywhere.
Best time of day
In Iowa, the Orange-crowned Warbler is most often listed on checklists started between 6 and 8 am (3.3% of those checklists).
Share of checklists started in each local hour that reported it. It reflects when people go birding as well as when birds are active. Grey hours have too few checklists (under 2% of the state’s, or under 200) to judge.Week-by-week table
Month
Days 1-7
8-14
15-21
22-end
January
0%
0%
0%
0%
February
0%
0%
0%
0%
March
0%
0%
0%
0%
April
0%
0.1%
1.3%
5.2%
May
10%
7.4%
2.6%
0.2%
June
0.1%
0%
0%
0%
July
0%
0%
0%
0%
August
0%
0%
0%
0%
September
0.2%
0.5%
1.7%
8.8%
October
13%
11%
7.3%
2.4%
November
0.3%
0.1%
0%
0%
December
0%
0%
0.1%
0%
Neighboring states
Missouri: arrives early September, 2 weeks earlier than Iowa
Wisconsin: arrives early September, 2 weeks earlier than Iowa
Minnesota: arrives early September, 2 weeks earlier than Iowa
Illinois: arrives early September, 2 weeks earlier than Iowa
Common questions
When do Orange-crowned Warblers arrive in Iowa?
Orange-crowned Warblers mostly pass through Iowa: they arrive in mid September, peak in early October (11% of checklists), and most are gone by late October.
When do Orange-crowned Warblers leave Iowa?
Most Orange-crowned Warblers have left Iowa by late October, when reports fall below half their usual rate. Stragglers are still reported until early November.
When is the best time to see a Orange-crowned Warbler in Iowa?
The Orange-crowned Warbler is reported most often in early October, on about 11% of Iowa checklists.
Where in Iowa are Orange-crowned Warblers seen most often?
By county, Sioux County, Montgomery County, and Cass County have the highest peak reporting rates for the Orange-crowned Warbler (counties with at least 200 checklists).