WhenToBird

Larus marinus · Laridae

When Do Great Black-backed Gulls Arrive in Wisconsin?

Adult Great Black-backed Gull
Photo: Rob Wadsworth, CC0 1.0 via iNaturalist

Great Black-backed Gulls are winter birds in Wisconsin: they arrive in late November, peak in the second week of January (1.5% of checklists), and most are gone by late March.

When to look

First arrivalsNov 22-30late November
Common byNov 22-30late November
PeakJan 8-14the second week of January
Most gone byMar 22-31late March

Best: the second week of January. First arrivals late November; most are gone by late March. Peak: on about 1.5% of Wisconsin checklists.

  1. Janpeak season
  2. Febpeak season
  3. Marcommon
  4. Apruncommon
  5. Mayrare
  6. Junrare
  7. Julnot usually seen
  8. Augnot usually seen
  9. Seprare
  10. Octrare
  11. Novuncommon
  12. Deccommon

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

0%0.5%1%1.5%2%Jan 1-7: 1.5% of 27925 checklistsJan 8-14: 1.6% of 18337 checklistsJan 15-21: 1.4% of 17370 checklistsJan 22-31: 1.2% of 23777 checklistsFeb 1-7: 1.5% of 16656 checklistsFeb 8-14: 1.0% of 18286 checklistsFeb 15-21: 0.7% of 24739 checklistsFeb 22-28: 1.1% of 20113 checklistsMar 1-7: 1.1% of 24024 checklistsMar 8-14: 0.9% of 26722 checklistsMar 15-21: 0.7% of 27238 checklistsMar 22-31: 0.5% of 40171 checklistsApr 1-7: 0.4% of 34961 checklistsApr 8-14: 0.2% of 39128 checklistsApr 15-21: 0.1% of 38887 checklistsApr 22-30: 0.1% of 57231 checklistsMay 1-7: 0.1% of 55115 checklistsMay 8-14: 0.1% of 63098 checklistsMay 15-21: 0.1% of 49821 checklistsMay 22-31: 0.1% of 56796 checklistsJun 1-7: 0.1% of 33621 checklistsJun 8-14: 0.1% of 31282 checklistsJun 15-21: 0.1% of 30186 checklistsJun 22-30: 0.1% of 35128 checklistsJul 1-7: 0.1% of 27088 checklistsJul 8-14: 0.1% of 23293 checklistsJul 15-21: 0.1% of 20933 checklistsJul 22-31: 0.1% of 27595 checklistsAug 1-7: 0.1% of 19147 checklistsAug 8-14: 0% of 18286 checklistsAug 15-21: 0.1% of 19195 checklistsAug 22-31: 0.1% of 28229 checklistsSep 1-7: 0.1% of 22408 checklistsSep 8-14: 0.1% of 20857 checklistsSep 15-21: 0.1% of 20707 checklistsSep 22-30: 0.1% of 26469 checklistsOct 1-7: 0.1% of 21069 checklistsOct 8-14: 0.1% of 21011 checklistsOct 15-21: 0.1% of 20006 checklistsOct 22-31: 0.2% of 26362 checklistsNov 1-7: 0.2% of 18928 checklistsNov 8-14: 0.3% of 17052 checklistsNov 15-21: 0.3% of 16291 checklistsNov 22-30: 0.7% of 20564 checklistsDec 1-7: 0.7% of 15354 checklistsDec 8-14: 0.9% of 16294 checklistsDec 15-21: 0.7% of 21430 checklistsDec 22-31: 1.0% 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 early March · 165 checklists that week, 9,747 in all24%
  2. Manitowoc CountyBest late January · 402 checklists that week, 26,017 in all15%
  3. Douglas CountyBest late March · 241 checklists that week, 14,015 in all12%
  4. Racine CountyBest the second week of January · 243 checklists that week, 18,400 in all6.8%
  5. Milwaukee CountyBest early January · 3185 checklists that week, 114,667 in all6.2%
  6. Sheboygan CountyBest mid January · 393 checklists that week, 25,419 in all5.1%

Best spots

Share of checklists at the peak
  1. Allouez BayDouglas County, best late March · 22 checklists that week, 113 in all78%
  2. Public SquareManitowoc County, best the second week of February · 26 checklists that week, 590 in all77%
  3. Manitowoc RiverManitowoc County, best the second week of March · 24 checklists that week, 771 in all55%
  4. KewauneeKewaunee County, best early March · 72 checklists that week, 2,215 in all48%
  5. Manitowoc Small Boat HarborManitowoc County, best mid March · 41 checklists that week, 2,200 in all47%

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

Best time of day

In Wisconsin, the Great Black-backed Gull is most often listed on checklists started between 1 and 3 pm (0.6% of those checklists).

0%0.5%1%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: 0.1% of 27016 checklists6 am: 0.1% of 83973 checklists7 am: 0.2% of 160717 checklists8 am: 0.3% of 160531 checklists9 am: 0.4% of 136968 checklists10 am: 0.5% of 119110 checklists11 am: 0.6% of 99116 checklists12 pm: 0.6% of 85078 checklists1 pm: 0.6% of 80688 checklists2 pm: 0.6% of 79140 checklists3 pm: 0.4% of 78599 checklists4 pm: 0.3% of 69767 checklists5 pm: 0.1% of 53229 checklists6 pm: 0.1% 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
January1.5%1.6%1.4%1.2%
February1.5%1.0%0.7%1.1%
March1.1%0.9%0.7%0.5%
April0.4%0.2%0.1%0.1%
May0.1%0.1%0.1%0.1%
June0.1%0.1%0.1%0.1%
July0.1%0.1%0.1%0.1%
August0.1%0%0.1%0.1%
September0.1%0.1%0.1%0.1%
October0.1%0.1%0.1%0.2%
November0.2%0.3%0.3%0.7%
December0.7%0.9%0.7%1.0%

Neighboring states

  • Michigan: arrives late October, 4 weeks earlier than Wisconsin
  • Ohio: arrives mid November, 1 week earlier than Wisconsin
  • Pennsylvania: arrives early October, 7 weeks earlier than Wisconsin
  • Virginia: arrives mid May, 23 weeks later than Wisconsin

Common questions

When do Great Black-backed Gulls arrive in Wisconsin?
Great Black-backed Gulls are winter birds in Wisconsin: they arrive in late November, peak in the second week of January (1.5% of checklists), and most are gone by late March.
When do Great Black-backed Gulls leave Wisconsin?
Most Great Black-backed Gulls have left Wisconsin by late March, when reports fall below half their usual rate.
When is the best time to see a Great Black-backed Gull in Wisconsin?
The Great Black-backed Gull is reported most often in the second week of January, on about 1.5% of Wisconsin checklists.
Where in Wisconsin are Great Black-backed Gulls seen most often?
By county, Kewaunee County, Manitowoc County, and Douglas County have the highest peak reporting rates for the Great Black-backed Gull (counties with at least 200 checklists).