WhenToBird

Larus smithsonianus · Laridae

When Do American Herring Gulls Arrive in Illinois?

Adult American Herring Gull
Photo: Priya Sandhu, CC BY 4.0 via iNaturalist

American Herring Gulls are in Illinois all year, but most are here in winter: numbers build from early November, peak in the second week of January (16% of checklists), and fall back by mid March. In the quietest week (mid June) they are still on about 4.0% of checklists.

When to look

Numbers buildNov 1-7early November
PeakJan 8-14the second week of January
Fall back byMar 15-21mid March
FewestJun 15-21mid June

Best: the second week of January. Here all year; numbers build from early November and fall back by mid March. Peak: on about 16% of Illinois checklists.

  1. Janpeak season
  2. Febpeak season
  3. Marpeak season
  4. Aprcommon
  5. Mayuncommon
  6. Jununcommon
  7. Julcommon
  8. Augcommon
  9. Sepcommon
  10. Octcommon
  11. Novpeak season
  12. Decpeak season

Darker months: more checklists report it. Outlined: peak month.

0%5%10%15%20%Jan 1-7: 16% of 29700 checklistsJan 8-14: 17% of 20189 checklistsJan 15-21: 16% of 19784 checklistsJan 22-31: 16% of 26641 checklistsFeb 1-7: 16% of 20478 checklistsFeb 8-14: 14% of 21967 checklistsFeb 15-21: 13% of 28735 checklistsFeb 22-28: 17% of 24223 checklistsMar 1-7: 15% of 26775 checklistsMar 8-14: 13% of 27579 checklistsMar 15-21: 12% of 27193 checklistsMar 22-31: 10% of 42278 checklistsApr 1-7: 8.6% of 34579 checklistsApr 8-14: 7.4% of 38290 checklistsApr 15-21: 7.4% of 39261 checklistsApr 22-30: 7.1% of 59584 checklistsMay 1-7: 5.7% of 60485 checklistsMay 8-14: 5.5% of 59647 checklistsMay 15-21: 6.5% of 43173 checklistsMay 22-31: 6.6% of 47913 checklistsJun 1-7: 4.9% of 31151 checklistsJun 8-14: 4.0% of 27692 checklistsJun 15-21: 3.9% of 23983 checklistsJun 22-30: 3.9% of 28448 checklistsJul 1-7: 4.7% of 21273 checklistsJul 8-14: 5.5% of 19284 checklistsJul 15-21: 6.7% of 17712 checklistsJul 22-31: 8.2% of 24500 checklistsAug 1-7: 8.1% of 18498 checklistsAug 8-14: 8.4% of 19331 checklistsAug 15-21: 8.0% of 19983 checklistsAug 22-31: 7.7% of 31892 checklistsSep 1-7: 7.6% of 26396 checklistsSep 8-14: 7.7% of 25011 checklistsSep 15-21: 7.4% of 23597 checklistsSep 22-30: 7.9% of 30638 checklistsOct 1-7: 7.5% of 23949 checklistsOct 8-14: 7.0% of 24412 checklistsOct 15-21: 8.3% of 22359 checklistsOct 22-31: 9.0% of 29794 checklistsNov 1-7: 10% of 21877 checklistsNov 8-14: 12% of 19742 checklistsNov 15-21: 14% of 18989 checklistsNov 22-30: 15% of 23905 checklistsDec 1-7: 15% of 16935 checklistsDec 8-14: 15% of 16687 checklistsDec 15-21: 13% of 20931 checklistsDec 22-31: 15% of 29011 checklistsJanFebMarAprMayJunJulAugSepOctNovDec
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
Second week of November

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.

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Where in Illinois

Best counties

Share of checklists at the peak
  1. Lake CountyBest early December · 1583 checklists that week, 113,940 in all39%
  2. Franklin CountyBest early December · 26 checklists that week, 1,745 in all37%
  3. Rock Island CountyBest late January · 313 checklists that week, 12,910 in all34%
  4. Putnam CountyBest the second week of January · 18 checklists that week, 3,333 in all32%
  5. Clinton CountyBest mid January · 233 checklists that week, 8,606 in all30%
  6. Cook CountyBest mid January · 5483 checklists that week, 432,644 in all28%

Best spots

Share of checklists at the peak
  1. Gun Club PondsCook County, best mid February · 31 checklists that week, 211 in all98%
  2. Douglas (Stephen)Cook County, best late February · 22 checklists that week, 1,219 in all98%
  3. Cooper Park - North & SouthTazewell County, best late October · 40 checklists that week, 750 in all98%
  4. Dead Stick Pond (Hegewisch Marsh)Cook County, best early February · 65 checklists that week, 361 in all97%
  5. Midewin National Tallgrass PrairieWill County, best early January · 44 checklists that week, 472 in all97%
  6. Ben Butterworth Memorial ParkwayRock Island County, best mid February · 28 checklists that week, 700 in all95%

Busy spots report more of everything; compare the checklist counts before you drive anywhere.

Best time of day

In Illinois, the American Herring Gull is most often listed on checklists started between 6 and 8 am (12% of those checklists).

0%5%10%15%12 am: too few checklists (484) to judge1 am: too few checklists (631) to judge2 am: too few checklists (485) to judge3 am: too few checklists (610) to judge4 am: too few checklists (2321) to judge5 am: too few checklists (23536) to judge6 am: 13% of 95511 checklists7 am: 11% of 164584 checklists8 am: 9.1% of 163654 checklists9 am: 9.2% of 141804 checklists10 am: 9.9% of 122882 checklists11 am: 10% of 100640 checklists12 pm: 10% of 89894 checklists1 pm: 9.7% of 82729 checklists2 pm: 9.7% of 79801 checklists3 pm: 8.8% of 82169 checklists4 pm: 6.8% of 75124 checklists5 pm: 5.5% of 57708 checklists6 pm: 4.0% of 41843 checklists7 pm: too few checklists (20943) to judge8 pm: too few checklists (6131) to judge9 pm: too few checklists (1677) to judge10 pm: too few checklists (843) to judge11 pm: too few checklists (448) to judge12a3a6a9a12p3p6p9p
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
MonthDays 1-78-1415-2122-end
January16%17%16%16%
February16%14%13%17%
March15%13%12%10%
April8.6%7.4%7.4%7.1%
May5.7%5.5%6.5%6.6%
June4.9%4.0%3.9%3.9%
July4.7%5.5%6.7%8.2%
August8.1%8.4%8.0%7.7%
September7.6%7.7%7.4%7.9%
October7.5%7.0%8.3%9.0%
November10%12%14%15%
December15%15%13%15%

Neighboring states

  • Indiana: arrives early July, 16 weeks earlier than Illinois
  • Wisconsin: arrives late October, 1 week earlier than Illinois
  • Michigan: arrives mid October, 2 weeks earlier than Illinois
  • Iowa: arrives early October, 4 weeks earlier than Illinois

Common questions

When do American Herring Gulls arrive in Illinois?
American Herring Gulls are in Illinois all year, but most are here in winter: numbers build from early November, peak in the second week of January (16% of checklists), and fall back by mid March. In the quietest week (mid June) they are still on about 4.0% of checklists.
When do American Herring Gulls leave Illinois?
American Herring Gulls never fully leave Illinois: numbers fall back below half their usual rate by mid March, but some are still reported in every week, about 4.0% of checklists at the low.
When is the best time to see a American Herring Gull in Illinois?
The American Herring Gull is reported most often in the second week of January, on about 16% of Illinois checklists.
Where in Illinois are American Herring Gulls seen most often?
By county, Lake County, Franklin County, and Rock Island County have the highest peak reporting rates for the American Herring Gull (counties with at least 200 checklists).