WhenToBird

Astur cooperii · Accipitridae

When Do Cooper's Hawks Arrive in Pennsylvania?

Adult male Cooper's Hawk
Photo: Shirley Zundell, CC BY 4.0 via iNaturalist

Cooper's Hawks are in Pennsylvania all year, but most are here in fall: numbers build from the second week of September, peak in the second week of October (9.4% of checklists), and fall back by mid November. In the quietest week (early June) they are still on about 2.3% of checklists.

When to look

Numbers buildSep 8-14the second week of September
PeakOct 8-14the second week of October
Fall back byNov 15-21mid November
FewestJun 1-7early June

Best: the second week of October. Here all year; numbers build from the second week of September and fall back by mid November. Peak: on about 9.4% of Pennsylvania checklists.

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

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

0%5%10%Jan 1-7: 5.2% of 47145 checklistsJan 8-14: 5.4% of 35840 checklistsJan 15-21: 5.3% of 35423 checklistsJan 22-31: 4.9% of 49126 checklistsFeb 1-7: 4.4% of 36366 checklistsFeb 8-14: 4.1% of 42248 checklistsFeb 15-21: 3.6% of 55888 checklistsFeb 22-28: 3.4% of 42050 checklistsMar 1-7: 3.6% of 42709 checklistsMar 8-14: 4.1% of 43985 checklistsMar 15-21: 4.4% of 44547 checklistsMar 22-31: 4.6% of 66940 checklistsApr 1-7: 4.8% of 51147 checklistsApr 8-14: 5.2% of 54868 checklistsApr 15-21: 5.5% of 57252 checklistsApr 22-30: 5.1% of 81727 checklistsMay 1-7: 4.1% of 76472 checklistsMay 8-14: 3.2% of 79341 checklistsMay 15-21: 2.8% of 61724 checklistsMay 22-31: 2.3% of 70722 checklistsJun 1-7: 2.3% of 45652 checklistsJun 8-14: 2.3% of 41810 checklistsJun 15-21: 2.4% of 38973 checklistsJun 22-30: 2.3% of 44255 checklistsJul 1-7: 2.5% of 34822 checklistsJul 8-14: 2.5% of 31104 checklistsJul 15-21: 2.4% of 29262 checklistsJul 22-31: 2.6% of 41436 checklistsAug 1-7: 3.4% of 29189 checklistsAug 8-14: 3.8% of 28840 checklistsAug 15-21: 4.2% of 29948 checklistsAug 22-31: 4.9% of 48235 checklistsSep 1-7: 6.0% of 37175 checklistsSep 8-14: 6.5% of 36527 checklistsSep 15-21: 8.4% of 37261 checklistsSep 22-30: 8.5% of 43583 checklistsOct 1-7: 9.3% of 35352 checklistsOct 8-14: 9.4% of 35560 checklistsOct 15-21: 9.5% of 33119 checklistsOct 22-31: 8.1% of 44654 checklistsNov 1-7: 7.4% of 32965 checklistsNov 8-14: 6.7% of 31305 checklistsNov 15-21: 6.2% of 29471 checklistsNov 22-30: 5.5% of 38642 checklistsDec 1-7: 5.7% of 28779 checklistsDec 8-14: 5.5% of 29486 checklistsDec 15-21: 6.0% of 37465 checklistsDec 22-31: 5.6% 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 all24%
  2. Perry CountyBest late October · 228 checklists that week, 10,281 in all22%
  3. Philadelphia CountyBest mid October · 1681 checklists that week, 96,503 in all18%
  4. Montgomery CountyBest the second week of October · 3552 checklists that week, 184,237 in all15%
  5. Delaware CountyBest the second week of October · 1369 checklists that week, 76,406 in all15%
  6. Carbon CountyBest late October · 410 checklists that week, 16,269 in all14%

Best spots

Share of checklists at the peak
  1. Rose Tree ParkDelaware County, best the second week of October · 70 checklists that week, 652 in all74%
  2. Waggoner's Gap Hawk WatchPerry County, best mid October · 36 checklists that week, 533 in all66%
  3. Hawk Mountain SanctuarySchuylkill County, best mid October · 149 checklists that week, 1,702 in all57%
  4. Sgl 217Lehigh County, best the second week of October · 23 checklists that week, 302 in all56%
  5. Temple UniversityPhiladelphia County, best mid April · 32 checklists that week, 1,147 in all50%

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

Best time of day

In Pennsylvania, the Cooper's Hawk is most often listed on checklists started between 7 and 9 am (6.0% of those checklists).

0%2%4%6%8%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: 5.3% of 92903 checklists7 am: 6.2% of 241233 checklists8 am: 5.9% of 271994 checklists9 am: 5.1% of 236842 checklists10 am: 4.8% of 199508 checklists11 am: 4.4% of 161893 checklists12 pm: 4.4% of 143945 checklists1 pm: 4.5% of 134352 checklists2 pm: 4.4% of 129692 checklists3 pm: 4.4% of 126132 checklists4 pm: 4.0% of 115055 checklists5 pm: 3.7% of 90719 checklists6 pm: 3.2% of 67534 checklists7 pm: 2.2% 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
January5.2%5.4%5.3%4.9%
February4.4%4.1%3.6%3.4%
March3.6%4.1%4.4%4.6%
April4.8%5.2%5.5%5.1%
May4.1%3.2%2.8%2.3%
June2.3%2.3%2.4%2.3%
July2.5%2.5%2.4%2.6%
August3.4%3.8%4.2%4.9%
September6.0%6.5%8.4%8.5%
October9.3%9.4%9.5%8.1%
November7.4%6.7%6.2%5.5%
December5.7%5.5%6.0%5.6%

Neighboring states

  • Maryland: arrives the second week of September, in the same week than Pennsylvania
  • District of Columbia: arrives mid July, 7 weeks earlier than Pennsylvania
  • Delaware: arrives early September, 1 week earlier than Pennsylvania
  • New Jersey: arrives mid September, 1 week later than Pennsylvania

Common questions

When do Cooper's Hawks arrive in Pennsylvania?
Cooper's Hawks are in Pennsylvania all year, but most are here in fall: numbers build from the second week of September, peak in the second week of October (9.4% of checklists), and fall back by mid November. In the quietest week (early June) they are still on about 2.3% of checklists.
When do Cooper's Hawks leave Pennsylvania?
Cooper's Hawks never fully leave Pennsylvania: numbers fall back below half their usual rate by mid November, but some are still reported in every week, about 2.3% of checklists at the low.
When is the best time to see a Cooper's Hawk in Pennsylvania?
The Cooper's Hawk is reported most often in the second week of October, on about 9.4% of Pennsylvania checklists.
Where in Pennsylvania are Cooper's Hawks seen most often?
By county, Schuylkill County, Perry County, and Philadelphia County have the highest peak reporting rates for the Cooper's Hawk (counties with at least 200 checklists).