Great Crested Flycatchers reach Illinois in mid April, are common by late April, peak in late May (25% of checklists), and most are gone by late August.
When to look
First arrivalsApr 15-21mid April
Common byApr 22-30late April
PeakMay 22-31late May
Most gone byAug 22-31late August
Best: late May. First arrivals mid April; most are gone by late August. Peak: on about 25% of Illinois checklists.
Jannot usually seen
Febnot usually seen
Marnot usually seen
Apruncommon
Maypeak season
Junpeak season
Julcommon
Auguncommon
Sepuncommon
Octnot usually seen
Novnot usually seen
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.
Steward ParkKendall County, best late May · 29 checklists that week, 788 in all85%
Busy spots report more of everything; compare the checklist counts before you drive anywhere.
Best time of day
In Illinois, the Great Crested Flycatcher is most often listed on checklists started between 6 and 8 am (10% 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%
0.4%
4.7%
May
14%
20%
26%
27%
June
22%
19%
17%
14%
July
14%
11%
11%
9.4%
August
7.6%
6.5%
6.5%
7.4%
September
6.1%
3.9%
1.4%
0.2%
October
0.1%
0%
0%
0.1%
November
0%
0%
0%
0%
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 late April, 1 week later than Illinois
Iowa: arrives late April, 1 week later than Illinois
Common questions
When do Great Crested Flycatchers arrive in Illinois?
Great Crested Flycatchers reach Illinois in mid April, are common by late April, peak in late May (25% of checklists), and most are gone by late August.
When do Great Crested Flycatchers leave Illinois?
Most Great Crested Flycatchers have left Illinois by late August, when reports fall below half their usual rate. Stragglers are still reported until mid September.
When is the best time to see a Great Crested Flycatcher in Illinois?
The Great Crested Flycatcher is reported most often in late May, on about 25% of Illinois checklists.
Where in Illinois are Great Crested Flycatchers seen most often?
By county, Schuyler County, Monroe County, and Mercer County have the highest peak reporting rates for the Great Crested Flycatcher (counties with at least 200 checklists).