WhenToBird

Chroicocephalus philadelphia · Laridae

Bonaparte's Gull: When and Where to See It

Adult Bonaparte's Gull
Photo: Kevin Krebs, CC BY 4.0 via iNaturalist

The Bonaparte's Gull reaches Idaho first, around early August, and Louisiana last, around early December.

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: 1.5% of 1114036 checklistsJan 8-14: 1.5% of 824708 checklistsJan 15-21: 1.4% of 825978 checklistsJan 22-31: 1.3% of 1105853 checklistsFeb 1-7: 1.1% of 779772 checklistsFeb 8-14: 0.9% of 864504 checklistsFeb 15-21: 0.7% of 1127933 checklistsFeb 22-28: 0.9% of 840124 checklistsMar 1-7: 0.9% of 839610 checklistsMar 8-14: 1.0% of 870138 checklistsMar 15-21: 1.2% of 898456 checklistsMar 22-31: 1.6% of 1335637 checklistsApr 1-7: 2.0% of 1030617 checklistsApr 8-14: 1.9% of 1124024 checklistsApr 15-21: 1.8% of 1194575 checklistsApr 22-30: 1.4% of 1675723 checklistsMay 1-7: 1.1% of 1449080 checklistsMay 8-14: 0.8% of 1538353 checklistsMay 15-21: 0.7% of 1219898 checklistsMay 22-31: 0.6% of 1452282 checklistsJun 1-7: 0.4% of 900636 checklistsJun 8-14: 0.3% of 829907 checklistsJun 15-21: 0.3% of 773255 checklistsJun 22-30: 0.3% of 916255 checklistsJul 1-7: 0.3% of 717733 checklistsJul 8-14: 0.4% of 658223 checklistsJul 15-21: 0.4% of 638752 checklistsJul 22-31: 0.6% of 895727 checklistsAug 1-7: 0.7% of 655651 checklistsAug 8-14: 0.8% of 650038 checklistsAug 15-21: 0.8% of 654639 checklistsAug 22-31: 0.7% of 974928 checklistsSep 1-7: 0.6% of 765914 checklistsSep 8-14: 0.6% of 738674 checklistsSep 15-21: 0.6% of 750433 checklistsSep 22-30: 0.6% of 944196 checklistsOct 1-7: 0.6% of 760106 checklistsOct 8-14: 0.8% of 793131 checklistsOct 15-21: 1.3% of 728727 checklistsOct 22-31: 2.1% of 959954 checklistsNov 1-7: 2.9% of 709464 checklistsNov 8-14: 3.1% of 693424 checklistsNov 15-21: 2.7% of 653952 checklistsNov 22-30: 2.5% of 871137 checklistsDec 1-7: 2.0% of 627591 checklistsDec 8-14: 1.7% of 642427 checklistsDec 15-21: 1.4% of 775638 checklistsDec 22-31: 1.5% 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 %
New JerseySummer visitorFeb 22-28Apr 1-7May 22-312.9%
PennsylvaniaSummer visitorMar 8-14Apr 8-14May 8-143.2%
West VirginiaSummer visitorMar 8-14Apr 1-7Apr 22-301.3%
District of ColumbiaPasses throughMar 15-21Apr 8-14Apr 22-306.1%
WisconsinPasses throughMar 22-31Apr 15-21Nov 22-306.0%
MinnesotaSummer visitorApr 1-7Apr 22-30May 22-313.0%
AlaskaSummer visitorApr 8-14May 8-14Oct 15-2111%
MaineSummer visitorJun 1-7Aug 8-14Nov 22-306.2%
OregonPasses throughJul 8-14Nov 1-7Dec 8-142.9%
New HampshireSummer visitorJul 8-14Aug 8-14Jan 1-71.6%
MontanaPasses throughJul 22-31Oct 22-31Nov 22-302.3%
IdahoPasses throughAug 1-7Nov 1-7Dec 8-143.1%
WyomingPasses throughSep 1-7Nov 1-7Dec 1-72.3%
MarylandSummer visitorOct 22-31Apr 1-7May 1-75.3%
VirginiaSummer visitorNov 1-7Apr 1-7Apr 15-212.7%
New MexicoPasses throughNov 1-7Nov 15-21Dec 8-141.2%
IndianaWinter visitorOct 1-7Nov 8-14Jan 1-76.3%
IllinoisWinter visitorOct 1-7Nov 8-14Jan 8-143.4%
MissouriWinter visitorOct 1-7Nov 8-14Jan 15-214.6%
NebraskaWinter visitorOct 1-7Nov 8-14Dec 8-143.7%
UtahWinter visitorOct 1-7Nov 1-7Dec 8-141.6%
Rhode IslandWinter visitorOct 8-14Jan 1-7Feb 8-143.3%
KansasWinter visitorOct 15-21Nov 15-21Jan 8-146.4%
CaliforniaWinter visitorOct 15-21Nov 15-21Feb 8-143.3%
OklahomaWinter visitorOct 22-31Dec 1-7Apr 1-79.2%
TennesseeWinter visitorOct 22-31Dec 8-14Apr 1-78.9%
KentuckyWinter visitorOct 22-31Nov 22-30Apr 8-145.4%
DelawareWinter visitorNov 1-7Jan 8-14May 1-76.0%
North CarolinaWinter visitorNov 1-7Dec 1-7Apr 1-74.7%
MississippiWinter visitorNov 8-14Jan 15-21Mar 22-317.0%
South CarolinaWinter visitorNov 8-14Jan 15-21Apr 1-76.8%
AlabamaWinter visitorNov 15-21Jan 1-7Apr 1-74.6%
ArkansasWinter visitorNov 15-21Jan 1-7Mar 8-144.2%
GeorgiaWinter visitorNov 22-30Mar 1-7Apr 1-71.8%
TexasWinter visitorNov 22-30Jan 15-21Apr 1-71.6%
LouisianaWinter visitorDec 1-7Jan 15-21Apr 1-71.4%
FloridaWinter visitorDec 8-14Jan 15-21Mar 22-313.7%
MassachusettsWinter visitorJun 15-21Nov 1-7Jan 8-142.9%
NevadaWinter visitorJul 1-7Nov 8-14Jan 1-71.8%
WashingtonWinter visitorJul 15-21Nov 1-7Jan 1-76.0%
VermontWinter visitorJul 15-21Nov 1-7Dec 1-72.9%
MichiganWinter visitorJul 22-31Nov 8-14Dec 15-217.3%
New YorkWinter visitorJul 22-31Nov 8-14Feb 1-73.7%
ConnecticutWinter visitorJul 22-31Mar 22-31May 1-71.2%
OhioWinter visitorAug 1-7Nov 8-14Jan 15-2112%
North DakotaWinter visitorSep 1-7Oct 22-31Dec 8-144.1%
IowaWinter visitorSep 15-21Nov 1-7Dec 8-146.9%
ColoradoWinter visitorSep 22-30Nov 8-14Jan 22-313.1%
South DakotaWinter visitorSep 22-30Nov 8-14Jan 1-74.7%

Winter visitor in: Georgia, Connecticut, Florida, Massachusetts, Nevada, Washington, Vermont, Michigan, New York

Passes through: District of Columbia, Wisconsin, Oregon, Montana

Summer visitor in: New Jersey, Pennsylvania, West Virginia, Minnesota, Alaska, Maine, New Hampshire, Maryland, Virginia