WhenToBird

Falco peregrinus · Falconidae

When Do Peregrine Falcons Arrive in Pennsylvania?

Adult Peregrine Falcon
Photo: Andrea Poggi, CC BY 4.0 via iNaturalist

Peregrine Falcons are winter birds in Pennsylvania: the first arrive in late July, they are common by early August, peak in early October (1.5% of checklists), and most are gone by the second week of April.

When to look

First arrivalsJul 22-31late July
Common byAug 1-7early August
PeakOct 1-7early October
Most gone byApr 8-14the second week of April

Best: early October. First arrivals late July; most are gone by the second week of April. Peak: on about 1.5% of Pennsylvania checklists.

  1. Jancommon
  2. Febcommon
  3. Marcommon
  4. Aprcommon
  5. Mayuncommon
  6. Jununcommon
  7. Juluncommon
  8. Augcommon
  9. Seppeak season
  10. Octpeak season
  11. Novcommon
  12. Deccommon

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

0%0.5%1%1.5%2%Jan 1-7: 0.9% of 47145 checklistsJan 8-14: 1.0% of 35840 checklistsJan 15-21: 0.8% of 35423 checklistsJan 22-31: 0.9% of 49126 checklistsFeb 1-7: 0.8% of 36366 checklistsFeb 8-14: 0.7% of 42248 checklistsFeb 15-21: 0.7% of 55888 checklistsFeb 22-28: 0.9% of 42050 checklistsMar 1-7: 0.7% of 42709 checklistsMar 8-14: 0.8% of 43985 checklistsMar 15-21: 0.7% of 44547 checklistsMar 22-31: 0.8% of 66940 checklistsApr 1-7: 0.7% of 51147 checklistsApr 8-14: 0.6% of 54868 checklistsApr 15-21: 0.5% of 57252 checklistsApr 22-30: 0.6% of 81727 checklistsMay 1-7: 0.4% of 76472 checklistsMay 8-14: 0.4% of 79341 checklistsMay 15-21: 0.5% of 61724 checklistsMay 22-31: 0.6% of 70722 checklistsJun 1-7: 0.6% of 45652 checklistsJun 8-14: 0.5% of 41810 checklistsJun 15-21: 0.5% of 38973 checklistsJun 22-30: 0.5% of 44255 checklistsJul 1-7: 0.5% of 34822 checklistsJul 8-14: 0.5% of 31104 checklistsJul 15-21: 0.4% of 29262 checklistsJul 22-31: 0.5% of 41436 checklistsAug 1-7: 0.8% of 29189 checklistsAug 8-14: 0.8% of 28840 checklistsAug 15-21: 0.8% of 29948 checklistsAug 22-31: 0.9% of 48235 checklistsSep 1-7: 0.9% of 37175 checklistsSep 8-14: 1.0% of 36527 checklistsSep 15-21: 1.1% of 37261 checklistsSep 22-30: 1.4% of 43583 checklistsOct 1-7: 1.5% of 35352 checklistsOct 8-14: 1.5% of 35560 checklistsOct 15-21: 1.2% of 33119 checklistsOct 22-31: 1.1% of 44654 checklistsNov 1-7: 1.0% of 32965 checklistsNov 8-14: 0.9% of 31305 checklistsNov 15-21: 0.8% of 29471 checklistsNov 22-30: 0.7% of 38642 checklistsDec 1-7: 0.8% of 28779 checklistsDec 8-14: 0.6% of 29486 checklistsDec 15-21: 0.7% of 37465 checklistsDec 22-31: 0.7% 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. Schuylkill CountyBest the second week of October · 384 checklists that week, 22,261 in all6.7%
  2. Philadelphia CountyBest early October · 1914 checklists that week, 96,503 in all6.3%
  3. Beaver CountyBest mid December · 139 checklists that week, 8,775 in all6.2%
  4. Lycoming CountyBest mid January · 452 checklists that week, 29,685 in all6.0%
  5. Mifflin CountyBest the second week of November · 63 checklists that week, 6,998 in all4.3%
  6. Perry CountyBest late September · 210 checklists that week, 10,281 in all4.3%

Best spots

Share of checklists at the peak
  1. Temple UniversityPhiladelphia County, best mid June · 20 checklists that week, 1,147 in all88%
  2. Bull CreekAllegheny County, best late February · 21 checklists that week, 243 in all68%
  3. CrombyChester County, best late May · 24 checklists that week, 629 in all66%
  4. Conestoga RiverLancaster County, best late February · 22 checklists that week, 710 in all60%
  5. Schuylkill River Open SpaceMontgomery County, best mid November · 34 checklists that week, 2,272 in all41%

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

Best time of day

In Pennsylvania, the Peregrine Falcon is most often listed on checklists started between 12 and 2 pm (0.9% of those checklists).

0%0.5%1%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: 0.8% of 92903 checklists7 am: 0.7% of 241233 checklists8 am: 0.6% of 271994 checklists9 am: 0.7% of 236842 checklists10 am: 0.8% of 199508 checklists11 am: 0.8% of 161893 checklists12 pm: 0.9% of 143945 checklists1 pm: 0.9% of 134352 checklists2 pm: 0.8% of 129692 checklists3 pm: 0.8% of 126132 checklists4 pm: 0.7% of 115055 checklists5 pm: 0.9% of 90719 checklists6 pm: 0.7% of 67534 checklists7 pm: 0.5% 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
January0.9%1.0%0.8%0.9%
February0.8%0.7%0.7%0.9%
March0.7%0.8%0.7%0.8%
April0.7%0.6%0.5%0.6%
May0.4%0.4%0.5%0.6%
June0.6%0.5%0.5%0.5%
July0.5%0.5%0.4%0.5%
August0.8%0.8%0.8%0.9%
September0.9%1.0%1.1%1.4%
October1.5%1.5%1.2%1.1%
November1.0%0.9%0.8%0.7%
December0.8%0.6%0.7%0.7%

Neighboring states

  • Maryland: arrives the second week of July, 2 weeks earlier than Pennsylvania
  • District of Columbia: arrives late September, 8 weeks later than Pennsylvania
  • Delaware: arrives late July, in the same week than Pennsylvania
  • New Jersey: arrives early July, 3 weeks earlier than Pennsylvania

Common questions

When do Peregrine Falcons arrive in Pennsylvania?
Peregrine Falcons are winter birds in Pennsylvania: the first arrive in late July, they are common by early August, peak in early October (1.5% of checklists), and most are gone by the second week of April.
When do Peregrine Falcons leave Pennsylvania?
Most Peregrine Falcons have left Pennsylvania by the second week of April, when reports fall below half their usual rate. Stragglers are still reported until early May.
When is the best time to see a Peregrine Falcon in Pennsylvania?
The Peregrine Falcon is reported most often in early October, on about 1.5% of Pennsylvania checklists.
Where in Pennsylvania are Peregrine Falcons seen most often?
By county, Schuylkill County, Philadelphia County, and Beaver County have the highest peak reporting rates for the Peregrine Falcon (counties with at least 200 checklists).