WhenToBird

Larus marinus · Laridae

Great Black-backed Gull: When and Where to See It

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

The Great Black-backed Gull reaches Pennsylvania first, around early October, and Wisconsin last, around late November.

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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0%1%2%3%4%Jan 1-7: 3.6% of 1114036 checklistsJan 8-14: 3.6% of 824708 checklistsJan 15-21: 3.6% of 825978 checklistsJan 22-31: 3.4% of 1105853 checklistsFeb 1-7: 3.2% of 779772 checklistsFeb 8-14: 2.7% of 864504 checklistsFeb 15-21: 2.3% of 1127933 checklistsFeb 22-28: 2.7% of 840124 checklistsMar 1-7: 2.3% of 839610 checklistsMar 8-14: 2.1% of 870138 checklistsMar 15-21: 2.0% of 898456 checklistsMar 22-31: 1.9% of 1335637 checklistsApr 1-7: 1.6% of 1030617 checklistsApr 8-14: 1.5% of 1124024 checklistsApr 15-21: 1.3% of 1194575 checklistsApr 22-30: 1.1% of 1675723 checklistsMay 1-7: 1.1% of 1449080 checklistsMay 8-14: 1.2% of 1538353 checklistsMay 15-21: 1.5% of 1219898 checklistsMay 22-31: 1.7% of 1452282 checklistsJun 1-7: 1.6% of 900636 checklistsJun 8-14: 1.6% of 829907 checklistsJun 15-21: 1.7% of 773255 checklistsJun 22-30: 1.8% of 916255 checklistsJul 1-7: 1.9% of 717733 checklistsJul 8-14: 2.2% of 658223 checklistsJul 15-21: 2.3% of 638752 checklistsJul 22-31: 2.6% of 895727 checklistsAug 1-7: 2.7% of 655651 checklistsAug 8-14: 2.9% of 650038 checklistsAug 15-21: 3.0% of 654639 checklistsAug 22-31: 2.7% of 974928 checklistsSep 1-7: 2.5% of 765914 checklistsSep 8-14: 2.4% of 738674 checklistsSep 15-21: 2.4% of 750433 checklistsSep 22-30: 2.4% of 944196 checklistsOct 1-7: 2.4% of 760106 checklistsOct 8-14: 2.5% of 793131 checklistsOct 15-21: 2.6% of 728727 checklistsOct 22-31: 2.6% of 959954 checklistsNov 1-7: 2.8% of 709464 checklistsNov 8-14: 3.0% of 693424 checklistsNov 15-21: 2.9% of 653952 checklistsNov 22-30: 3.1% of 871137 checklistsDec 1-7: 3.0% of 627591 checklistsDec 8-14: 2.8% of 642427 checklistsDec 15-21: 2.7% of 775638 checklistsDec 22-31: 3.4% of 1132751 checklistsJanFebMarAprMayJunJulAugSepOctNovDec
Share of complete checklists reporting it, by week (4 per month). Grey bars: fewer than 10 checklists, not counted.

Pooled across every state in the data, so it leans toward states with the most birders.

States, in order of first arrivals

StatePatternFirst arrivalsPeakMost gone byPeak %
Rhode IslandAll year, most in summerJun 15-21Aug 1-7Sep 15-2137%
ConnecticutAll year, most in summerJul 1-7Aug 8-14Sep 8-1413%
MaineAll year, most in fallJul 8-14Aug 8-14Nov 22-3018%
PennsylvaniaWinter visitorOct 1-7Jan 8-14Apr 1-72.3%
District of ColumbiaWinter visitorOct 22-31Dec 15-21Feb 8-1413%
MichiganWinter visitorOct 22-31Jan 1-7Mar 22-312.7%
FloridaWinter visitorOct 22-31Jan 22-31Mar 22-311.2%
DelawareAll year, most in winterNov 1-7Jan 8-14Mar 8-1418%
New YorkAll year, most in winterNov 1-7Jan 8-14Mar 1-716%
OhioWinter visitorNov 15-21Jan 15-21Apr 1-73.6%
WisconsinWinter visitorNov 22-30Jan 8-14Mar 22-311.5%
North CarolinaWinter visitorMay 15-21Jan 1-7Mar 8-145.1%
VirginiaWinter visitorMay 15-21Jan 22-31Mar 22-316.4%
MarylandWinter visitorMay 22-31Nov 15-21Mar 22-318.1%
New HampshireAll year, most in fallJul 22-31Dec 1-7Jan 22-318.0%
VermontWinter visitorJul 22-31Jan 8-14Mar 15-213.4%
South CarolinaWinter visitorAug 22-31Jan 8-14Mar 15-211.4%
New JerseyYear-round–Jan 15-21–17%
MassachusettsYear-round–Aug 8-14–17%

Winter visitor in: North Carolina, Virginia, Maryland, New Hampshire, Vermont, South Carolina

Passes through: Connecticut

Summer visitor in: Rhode Island, Maine