Yellow-rumped Warblers are winter birds in Illinois: the first arrive in late August, they are common by early September, peak in the second week of October (44% of checklists), and most are gone by late May.
When to look
First arrivalsAug 22-31late August
Common bySep 1-7early September
PeakOct 8-14the second week of October
Most gone byMay 22-31late May
Best: the second week of October. First arrivals late August; most are gone by late May. Peak: on about 44% of Illinois checklists.
Janrare
Febnot usually seen
Marrare
Aprpeak season
Maycommon
Junnot usually seen
Julnot usually seen
Augnot usually seen
Sepcommon
Octpeak season
Novuncommon
Decrare
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 Illinois 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.
Jon J. Duerr Forest PreserveKane County, best the second week of October · 25 checklists that week, 1,472 in all90%
Bemis Woods NorthCook County, best the second week of October · 23 checklists that week, 803 in all89%
Linne WoodsCook County, best late April · 80 checklists that week, 1,012 in all88%
Busy spots report more of everything; compare the checklist counts before you drive anywhere.
Best time of day
In Illinois, the Yellow-rumped Warbler is most often listed on checklists started between 6 and 8 am (15% 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
1.6%
1.5%
1.3%
1.6%
February
1.5%
1.3%
1.3%
1.4%
March
1.1%
1.3%
1.5%
2.9%
April
9.9%
24%
31%
35%
May
36%
27%
13%
1.6%
June
0.1%
0.1%
0.1%
0.1%
July
0%
0%
0.1%
0.1%
August
0.1%
0.1%
0.2%
0.8%
September
2.3%
4.4%
10%
31%
October
44%
47%
42%
26%
November
13%
6.0%
4.0%
3.0%
December
2.2%
2.4%
3.1%
3.0%
Neighboring states
Indiana: arrives early September, 1 week later than Illinois
Wisconsin: arrives late March, 20 weeks earlier than Illinois
Michigan: arrives late March, 20 weeks earlier than Illinois
Iowa: arrives early September, 1 week later than Illinois
Common questions
When do Yellow-rumped Warblers arrive in Illinois?
Yellow-rumped Warblers are winter birds in Illinois: the first arrive in late August, they are common by early September, peak in the second week of October (44% of checklists), and most are gone by late May.
When do Yellow-rumped Warblers leave Illinois?
Most Yellow-rumped Warblers have left Illinois by late May, when reports fall below half their usual rate.
When is the best time to see a Yellow-rumped Warbler in Illinois?
The Yellow-rumped Warbler is reported most often in the second week of October, on about 44% of Illinois checklists.
Where in Illinois are Yellow-rumped Warblers seen most often?
By county, Clark County, Iroquois County, and Crawford County have the highest peak reporting rates for the Yellow-rumped Warbler (counties with at least 200 checklists).