WhenToBird

Larus delawarensis · Laridae

When Do Ring-billed Gulls Arrive in Pennsylvania?

Adult Ring-billed Gull
Photo: Isaac Krone, CC BY 4.0 via iNaturalist

Ring-billed Gulls are winter birds in Pennsylvania: the first arrive in early July, they are common by the second week of August, peak in early March (15% of checklists), and most are gone by the second week of April.

When to look

First arrivalsJul 1-7early July
Common byAug 8-14the second week of August
PeakMar 1-7early March
Most gone byApr 8-14the second week of April

Best: early March. First arrivals early July; most are gone by the second week of April. Peak: on about 15% of Pennsylvania checklists.

  1. Janpeak season
  2. Febpeak season
  3. Marpeak season
  4. Aprcommon
  5. Mayuncommon
  6. Junrare
  7. Juluncommon
  8. Auguncommon
  9. Sepuncommon
  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: 13% of 47145 checklistsJan 8-14: 13% of 35840 checklistsJan 15-21: 12% of 35423 checklistsJan 22-31: 12% of 49126 checklistsFeb 1-7: 11% of 36366 checklistsFeb 8-14: 10% of 42248 checklistsFeb 15-21: 10% of 55888 checklistsFeb 22-28: 15% of 42050 checklistsMar 1-7: 15% of 42709 checklistsMar 8-14: 14% of 43985 checklistsMar 15-21: 12% of 44547 checklistsMar 22-31: 9.2% of 66940 checklistsApr 1-7: 6.4% of 51147 checklistsApr 8-14: 5.2% of 54868 checklistsApr 15-21: 4.6% of 57252 checklistsApr 22-30: 3.4% of 81727 checklistsMay 1-7: 3.0% of 76472 checklistsMay 8-14: 2.8% of 79341 checklistsMay 15-21: 2.8% of 61724 checklistsMay 22-31: 1.8% of 70722 checklistsJun 1-7: 1.1% of 45652 checklistsJun 8-14: 0.9% of 41810 checklistsJun 15-21: 1.1% of 38973 checklistsJun 22-30: 1.3% of 44255 checklistsJul 1-7: 2.0% of 34822 checklistsJul 8-14: 3.0% of 31104 checklistsJul 15-21: 4.2% of 29262 checklistsJul 22-31: 4.2% of 41436 checklistsAug 1-7: 5.0% of 29189 checklistsAug 8-14: 5.6% of 28840 checklistsAug 15-21: 5.1% of 29948 checklistsAug 22-31: 4.9% of 48235 checklistsSep 1-7: 4.7% of 37175 checklistsSep 8-14: 4.2% of 36527 checklistsSep 15-21: 4.1% of 37261 checklistsSep 22-30: 4.6% of 43583 checklistsOct 1-7: 4.9% of 35352 checklistsOct 8-14: 5.3% of 35560 checklistsOct 15-21: 5.7% of 33119 checklistsOct 22-31: 7.2% of 44654 checklistsNov 1-7: 8.2% of 32965 checklistsNov 8-14: 11% of 31305 checklistsNov 15-21: 11% of 29471 checklistsNov 22-30: 13% of 38642 checklistsDec 1-7: 13% of 28779 checklistsDec 8-14: 12% of 29486 checklistsDec 15-21: 10% of 37465 checklistsDec 22-31: 11% of 50651 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 Pennsylvania 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 Pennsylvania

Best counties

Share of checklists at the peak
  1. Philadelphia CountyBest late December · 2048 checklists that week, 96,503 in all48%
  2. Erie CountyBest the second week of December · 645 checklists that week, 49,012 in all43%
  3. Dauphin CountyBest the second week of March · 891 checklists that week, 35,877 in all40%
  4. Mercer CountyBest the second week of March · 456 checklists that week, 17,853 in all38%
  5. Crawford CountyBest the second week of November · 353 checklists that week, 23,552 in all33%
  6. Bucks CountyBest mid November · 1435 checklists that week, 95,030 in all33%

Best spots

Share of checklists at the peak
  1. Governor Printz ParkDelaware County, best early January · 38 checklists that week, 739 in all100%
  2. Pymatuning ReservoirCrawford County, best the second week of March · 20 checklists that week, 223 in all100%
  3. Dry Brooks Day-Use AreaBerks County, best the second week of November · 20 checklists that week, 1,039 in all100%
  4. McClure ParkDelaware County, best late January · 35 checklists that week, 541 in all100%
  5. Pymatuning State ParkCrawford County, best the second week of March · 28 checklists that week, 1,001 in all100%

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

Best time of day

In Pennsylvania, the Ring-billed Gull is most often listed on checklists started between 1 and 3 pm (8.9% of those checklists).

0%5%10%12 am: too few checklists (1558) to judge1 am: too few checklists (1136) to judge2 am: too few checklists (839) to judge3 am: too few checklists (842) to judge4 am: too few checklists (2550) to judge5 am: too few checklists (18294) to judge6 am: 5.2% of 92903 checklists7 am: 6.3% of 241233 checklists8 am: 6.4% of 271994 checklists9 am: 7.0% of 236842 checklists10 am: 7.6% of 199508 checklists11 am: 8.0% of 161893 checklists12 pm: 8.4% of 143945 checklists1 pm: 8.9% of 134352 checklists2 pm: 8.9% of 129692 checklists3 pm: 8.2% of 126132 checklists4 pm: 6.8% of 115055 checklists5 pm: 5.1% of 90719 checklists6 pm: 3.8% of 67534 checklists7 pm: 2.5% of 43004 checklists8 pm: too few checklists (13966) to judge9 pm: too few checklists (3913) to judge10 pm: too few checklists (1989) to judge11 pm: too few checklists (1146) 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
January13%13%12%12%
February11%10%10%15%
March15%14%12%9.2%
April6.4%5.2%4.6%3.4%
May3.0%2.8%2.8%1.8%
June1.1%0.9%1.1%1.3%
July2.0%3.0%4.2%4.2%
August5.0%5.6%5.1%4.9%
September4.7%4.2%4.1%4.6%
October4.9%5.3%5.7%7.2%
November8.2%11%11%13%
December13%12%10%11%

Neighboring states

  • Maryland: arrives late June, 1 week earlier than Pennsylvania
  • District of Columbia: arrives early July, in the same week than Pennsylvania
  • Delaware: arrives late October, 15 weeks later than Pennsylvania
  • New Jersey: arrives mid October, 14 weeks later than Pennsylvania

Common questions

When do Ring-billed Gulls arrive in Pennsylvania?
Ring-billed Gulls are winter birds in Pennsylvania: the first arrive in early July, they are common by the second week of August, peak in early March (15% of checklists), and most are gone by the second week of April.
When do Ring-billed Gulls leave Pennsylvania?
Most Ring-billed Gulls have left Pennsylvania by the second week of April, when reports fall below half their usual rate. Stragglers are still reported until late May.
When is the best time to see a Ring-billed Gull in Pennsylvania?
The Ring-billed Gull is reported most often in early March, on about 15% of Pennsylvania checklists.
Where in Pennsylvania are Ring-billed Gulls seen most often?
By county, Philadelphia County, Erie County, and Dauphin County have the highest peak reporting rates for the Ring-billed Gull (counties with at least 200 checklists).