Blue-headed Vireos mostly pass through Illinois: they arrive in mid April, peak in the second week of May (5.9% of checklists), and most are gone by early June.
When to look
First arrivalsApr 15-21mid April
Common byApr 15-21mid April
PeakMay 8-14the second week of May
Most gone byJun 1-7early June
Best: the second week of May. First arrivals mid April; most are gone by early June. Peak: on about 5.9% of Illinois checklists.
Jannot usually seen
Febnot usually seen
Marnot usually seen
Aprcommon
Maypeak season
Junrare
Julnot usually seen
Augnot usually seen
Sepcommon
Octcommon
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 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.
Busy spots report more of everything; compare the checklist counts before you drive anywhere.
Best time of day
In Illinois, the Blue-headed Vireo is most often listed on checklists started between 6 and 8 am (1.9% 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
0.1%
0%
0%
0.1%
February
0%
0%
0%
0%
March
0%
0%
0%
0%
April
0%
0.1%
0.3%
2.5%
May
5.9%
6.9%
4.4%
1.2%
June
0.1%
0.1%
0%
0.1%
July
0%
0%
0%
0%
August
0%
0.1%
0.1%
0.1%
September
0.3%
0.7%
1.3%
2.8%
October
2.9%
2.4%
1.5%
0.6%
November
0.1%
0.1%
0.1%
0.1%
December
0%
0%
0%
0%
Neighboring states
Indiana: arrives mid April, in the same week than Illinois
Wisconsin: arrives late April, 1 week later than Illinois
Michigan: arrives mid April, in the same week than Illinois
Iowa: arrives late April, 1 week later than Illinois
Common questions
When do Blue-headed Vireos arrive in Illinois?
Blue-headed Vireos mostly pass through Illinois: they arrive in mid April, peak in the second week of May (5.9% of checklists), and most are gone by early June.
When do Blue-headed Vireos leave Illinois?
Most Blue-headed Vireos have left Illinois by early June, when reports fall below half their usual rate.
When is the best time to see a Blue-headed Vireo in Illinois?
The Blue-headed Vireo is reported most often in the second week of May, on about 5.9% of Illinois checklists.
Where in Illinois are Blue-headed Vireos seen most often?
By county, Edwards County, Richland County, and Wayne County have the highest peak reporting rates for the Blue-headed Vireo (counties with at least 200 checklists).