Greater Yellowlegses arrive in Illinois in late March, peak in mid April (5.1% of checklists), and most are gone by the second week of May.
When to look
First arrivalsMar 22-31late March
Common byMar 22-31late March
PeakApr 15-21mid April
Most gone byMay 8-14the second week of May
Best: mid April. First arrivals late March; most are gone by the second week of May. Peak: on about 5.1% of Illinois checklists.
Jannot usually seen
Febnot usually seen
Maruncommon
Aprpeak season
Maycommon
Junrare
Julcommon
Augpeak season
Sepcommon
Octcommon
Novuncommon
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 Greater Yellowlegs is most often listed on checklists started between 5 and 7 pm (2.1% 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
0.1%
0%
0.1%
0.1%
March
0.1%
0.1%
0.3%
1.2%
April
2.0%
3.7%
5.4%
5.8%
May
3.3%
1.6%
1.0%
0.2%
June
0.1%
0.1%
0.1%
0.1%
July
0.8%
1.5%
2.0%
2.6%
August
3.8%
4.1%
4.6%
4.2%
September
2.9%
2.1%
2.0%
2.2%
October
2.1%
2.0%
2.3%
2.3%
November
1.9%
1.0%
0.3%
0.1%
December
0.1%
0%
0.1%
0%
Neighboring states
Indiana: arrives mid March, 1 week earlier than Illinois
Wisconsin: arrives early April, 1 week later than Illinois
Michigan: arrives early April, 1 week later than Illinois
Iowa: arrives late March, in the same week than Illinois
Common questions
When do Greater Yellowlegses arrive in Illinois?
Greater Yellowlegses arrive in Illinois in late March, peak in mid April (5.1% of checklists), and most are gone by the second week of May.
When do Greater Yellowlegses leave Illinois?
Most Greater Yellowlegses have left Illinois by the second week of May, when reports fall below half their usual rate. Stragglers are still reported until mid May.
When is the best time to see a Greater Yellowlegs in Illinois?
The Greater Yellowlegs is reported most often in mid April, on about 5.1% of Illinois checklists.
Where in Illinois are Greater Yellowlegses seen most often?
By county, Moultrie County, Fulton County, and Crawford County have the highest peak reporting rates for the Greater Yellowlegs (counties with at least 200 checklists).