WhenToBird

Larus smithsonianus · Laridae

When Do American Herring Gulls Arrive in Wisconsin?

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

American Herring Gulls are in Wisconsin all year, but most are here in winter: numbers build from late October, peak in early December (17% of checklists), and fall back by mid January. In the quietest week (early July) they are still on about 5.0% of checklists.

When to look

Numbers buildOct 22-31late October
PeakDec 1-7early December
Fall back byJan 15-21mid January
FewestJul 1-7early July

Best: early December. Here all year; numbers build from late October and fall back by mid January. Peak: on about 17% of Wisconsin checklists.

  1. Janpeak season
  2. Febcommon
  3. Marpeak season
  4. Aprcommon
  5. Maycommon
  6. Juncommon
  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 27925 checklistsJan 8-14: 13% of 18337 checklistsJan 15-21: 11% of 17370 checklistsJan 22-31: 9.3% of 23777 checklistsFeb 1-7: 10% of 16656 checklistsFeb 8-14: 9.3% of 18286 checklistsFeb 15-21: 8.8% of 24739 checklistsFeb 22-28: 13% of 20113 checklistsMar 1-7: 15% of 24024 checklistsMar 8-14: 15% of 26722 checklistsMar 15-21: 14% of 27238 checklistsMar 22-31: 13% of 40171 checklistsApr 1-7: 12% of 34961 checklistsApr 8-14: 10% of 39128 checklistsApr 15-21: 9.7% of 38887 checklistsApr 22-30: 9.8% of 57231 checklistsMay 1-7: 8.6% of 55115 checklistsMay 8-14: 6.9% of 63098 checklistsMay 15-21: 8.1% of 49821 checklistsMay 22-31: 7.9% of 56796 checklistsJun 1-7: 6.1% of 33621 checklistsJun 8-14: 5.3% of 31282 checklistsJun 15-21: 5.5% of 30186 checklistsJun 22-30: 4.9% of 35128 checklistsJul 1-7: 4.7% of 27088 checklistsJul 8-14: 5.5% of 23293 checklistsJul 15-21: 5.8% of 20933 checklistsJul 22-31: 7.4% of 27595 checklistsAug 1-7: 7.2% of 19147 checklistsAug 8-14: 7.3% of 18286 checklistsAug 15-21: 8.3% of 19195 checklistsAug 22-31: 7.8% of 28229 checklistsSep 1-7: 7.9% of 22408 checklistsSep 8-14: 8.1% of 20857 checklistsSep 15-21: 9.4% of 20707 checklistsSep 22-30: 8.9% of 26469 checklistsOct 1-7: 8.6% of 21069 checklistsOct 8-14: 8.4% of 21011 checklistsOct 15-21: 9.5% of 20006 checklistsOct 22-31: 12% of 26362 checklistsNov 1-7: 15% of 18928 checklistsNov 8-14: 15% of 17052 checklistsNov 15-21: 16% of 16291 checklistsNov 22-30: 17% of 20564 checklistsDec 1-7: 17% of 15354 checklistsDec 8-14: 16% of 16294 checklistsDec 15-21: 15% of 21430 checklistsDec 22-31: 13% of 26314 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 Wisconsin 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 Wisconsin

Best counties

Share of checklists at the peak
  1. Kewaunee CountyBest mid November · 102 checklists that week, 9,747 in all61%
  2. Douglas CountyBest late November · 200 checklists that week, 14,015 in all57%
  3. Racine CountyBest late November · 313 checklists that week, 18,400 in all44%
  4. Marinette CountyBest early April · 328 checklists that week, 16,075 in all44%
  5. Manitowoc CountyBest early December · 289 checklists that week, 26,017 in all41%
  6. Kenosha CountyBest late November · 175 checklists that week, 11,654 in all37%

Best spots

Share of checklists at the peak
  1. Allouez BayDouglas County, best late March · 22 checklists that week, 113 in all100%
  2. Public SquareManitowoc County, best late January · 40 checklists that week, 590 in all99%
  3. Milwaukee BayMilwaukee County, best the second week of July · 38 checklists that week, 574 in all98%

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

Best time of day

In Wisconsin, the American Herring Gull is most often listed on checklists started between 12 and 2 pm (11% of those checklists).

0%5%10%15%12 am: too few checklists (993) to judge1 am: too few checklists (844) to judge2 am: too few checklists (839) to judge3 am: too few checklists (1488) to judge4 am: too few checklists (5344) to judge5 am: 6.2% of 27016 checklists6 am: 9.3% of 83973 checklists7 am: 9.8% of 160717 checklists8 am: 11% of 160531 checklists9 am: 11% of 136968 checklists10 am: 11% of 119110 checklists11 am: 11% of 99116 checklists12 pm: 11% of 85078 checklists1 pm: 11% of 80688 checklists2 pm: 11% of 79140 checklists3 pm: 10% of 78599 checklists4 pm: 8.8% of 69767 checklists5 pm: 7.7% of 53229 checklists6 pm: 6.5% of 38769 checklists7 pm: too few checklists (24396) to judge8 pm: too few checklists (10155) to judge9 pm: too few checklists (4990) to judge10 pm: too few checklists (2463) to judge11 pm: too few checklists (1281) 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%13%11%9.3%
February10%9.3%8.8%13%
March15%15%14%13%
April12%10%9.7%9.8%
May8.6%6.9%8.1%7.9%
June6.1%5.3%5.5%4.9%
July4.7%5.5%5.8%7.4%
August7.2%7.3%8.3%7.8%
September7.9%8.1%9.4%8.9%
October8.6%8.4%9.5%12%
November15%15%16%17%
December17%16%15%13%

Neighboring states

  • Illinois: arrives early November, 1 week later than Wisconsin
  • Iowa: arrives early October, 3 weeks earlier than Wisconsin
  • Michigan: arrives mid October, 1 week earlier than Wisconsin
  • Minnesota: arrives mid May, 21 weeks earlier than Wisconsin

Common questions

When do American Herring Gulls arrive in Wisconsin?
American Herring Gulls are in Wisconsin all year, but most are here in winter: numbers build from late October, peak in early December (17% of checklists), and fall back by mid January. In the quietest week (early July) they are still on about 5.0% of checklists.
When do American Herring Gulls leave Wisconsin?
American Herring Gulls never fully leave Wisconsin: numbers fall back below half their usual rate by mid January, but some are still reported in every week, about 5.0% of checklists at the low.
When is the best time to see a American Herring Gull in Wisconsin?
The American Herring Gull is reported most often in early December, on about 17% of Wisconsin checklists.
Where in Wisconsin are American Herring Gulls seen most often?
By county, Kewaunee County, Douglas County, and Racine County have the highest peak reporting rates for the American Herring Gull (counties with at least 200 checklists).