WhenToBird

Falco columbarius · Falconidae

When Do Merlins Arrive in Pennsylvania?

Adult female Merlin
Photo: Cricket Raspet, CC BY 4.0 via iNaturalist

Merlins are winter birds in Pennsylvania: they arrive in late August, peak in the second week of October (2.2% of checklists), and most are gone by the second week of April.

When to look

First arrivalsAug 22-31late August
Common byAug 22-31late August
PeakOct 8-14the second week of October
Most gone byApr 8-14the second week of April

Best: the second week of October. First arrivals late August; most are gone by the second week of April. Peak: on about 2.2% of Pennsylvania checklists.

  1. Jancommon
  2. Febcommon
  3. Maruncommon
  4. Apruncommon
  5. Mayuncommon
  6. Junrare
  7. Julrare
  8. Auguncommon
  9. Seppeak season
  10. Octpeak season
  11. Novpeak season
  12. Deccommon

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

0%1%2%3%Jan 1-7: 1.0% of 47145 checklistsJan 8-14: 0.9% of 35840 checklistsJan 15-21: 1.0% of 35423 checklistsJan 22-31: 1.0% of 49126 checklistsFeb 1-7: 0.9% of 36366 checklistsFeb 8-14: 0.7% of 42248 checklistsFeb 15-21: 0.5% of 55888 checklistsFeb 22-28: 0.7% of 42050 checklistsMar 1-7: 0.5% of 42709 checklistsMar 8-14: 0.6% of 43985 checklistsMar 15-21: 0.7% of 44547 checklistsMar 22-31: 0.5% of 66940 checklistsApr 1-7: 0.6% of 51147 checklistsApr 8-14: 0.6% of 54868 checklistsApr 15-21: 0.6% of 57252 checklistsApr 22-30: 0.4% of 81727 checklistsMay 1-7: 0.3% of 76472 checklistsMay 8-14: 0.2% of 79341 checklistsMay 15-21: 0.1% of 61724 checklistsMay 22-31: 0.1% of 70722 checklistsJun 1-7: 0.1% of 45652 checklistsJun 8-14: 0.1% of 41810 checklistsJun 15-21: 0.1% of 38973 checklistsJun 22-30: 0.1% of 44255 checklistsJul 1-7: 0.3% of 34822 checklistsJul 8-14: 0.2% of 31104 checklistsJul 15-21: 0.3% of 29262 checklistsJul 22-31: 0.3% of 41436 checklistsAug 1-7: 0.4% of 29189 checklistsAug 8-14: 0.4% of 28840 checklistsAug 15-21: 0.4% of 29948 checklistsAug 22-31: 0.6% of 48235 checklistsSep 1-7: 1.2% of 37175 checklistsSep 8-14: 1.8% of 36527 checklistsSep 15-21: 2.1% of 37261 checklistsSep 22-30: 2.1% of 43583 checklistsOct 1-7: 2.1% of 35352 checklistsOct 8-14: 2.3% of 35560 checklistsOct 15-21: 2.1% of 33119 checklistsOct 22-31: 1.9% of 44654 checklistsNov 1-7: 1.5% of 32965 checklistsNov 8-14: 1.5% of 31305 checklistsNov 15-21: 1.2% of 29471 checklistsNov 22-30: 1.2% of 38642 checklistsDec 1-7: 1.0% of 28779 checklistsDec 8-14: 0.9% of 29486 checklistsDec 15-21: 1.2% of 37465 checklistsDec 22-31: 1.0% 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 mid October · 448 checklists that week, 22,261 in all12%
  2. Perry CountyBest mid October · 200 checklists that week, 10,281 in all9.0%
  3. Mifflin CountyBest mid October · 57 checklists that week, 6,998 in all6.9%
  4. Carbon CountyBest the second week of October · 252 checklists that week, 16,269 in all5.8%
  5. Luzerne CountyBest late September · 642 checklists that week, 34,996 in all5.0%
  6. Northampton CountyBest early October · 848 checklists that week, 45,480 in all4.7%

Best spots

Share of checklists at the peak
  1. State Game Land 168Northampton County, best late October · 22 checklists that week, 296 in all38%
  2. Hawk Mountain SanctuarySchuylkill County, best mid October · 149 checklists that week, 1,702 in all38%
  3. Sgl 217Lehigh County, best the second week of October · 23 checklists that week, 302 in all33%
  4. Waggoner's Gap Hawk WatchPerry County, best mid October · 36 checklists that week, 533 in all32%
  5. Luzerne County Levee TrailLuzerne County, best mid September · 20 checklists that week, 691 in all28%

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

Best time of day

In Pennsylvania, the Merlin is most often listed on checklists started between 6 and 8 am (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: 1.0% of 241233 checklists8 am: 0.8% of 271994 checklists9 am: 0.7% of 236842 checklists10 am: 0.8% of 199508 checklists11 am: 0.7% of 161893 checklists12 pm: 0.7% of 143945 checklists1 pm: 0.8% of 134352 checklists2 pm: 0.8% of 129692 checklists3 pm: 0.9% of 126132 checklists4 pm: 0.8% of 115055 checklists5 pm: 0.8% of 90719 checklists6 pm: 0.6% of 67534 checklists7 pm: 0.3% 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
January1.0%0.9%1.0%1.0%
February0.9%0.7%0.5%0.7%
March0.5%0.6%0.7%0.5%
April0.6%0.6%0.6%0.4%
May0.3%0.2%0.1%0.1%
June0.1%0.1%0.1%0.1%
July0.3%0.2%0.3%0.3%
August0.4%0.4%0.4%0.6%
September1.2%1.8%2.1%2.1%
October2.1%2.3%2.1%1.9%
November1.5%1.5%1.2%1.2%
December1.0%0.9%1.2%1.0%

Neighboring states

  • Maryland: arrives early September, 1 week later than Pennsylvania
  • District of Columbia: arrives early September, 1 week later than Pennsylvania
  • Delaware: arrives early September, 1 week later than Pennsylvania
  • New Jersey: arrives late August, in the same week than Pennsylvania

Common questions

When do Merlins arrive in Pennsylvania?
Merlins are winter birds in Pennsylvania: they arrive in late August, peak in the second week of October (2.2% of checklists), and most are gone by the second week of April.
When do Merlins leave Pennsylvania?
Most Merlins have left Pennsylvania by the second week of April, when reports fall below half their usual rate.
When is the best time to see a Merlin in Pennsylvania?
The Merlin is reported most often in the second week of October, on about 2.2% of Pennsylvania checklists.
Where in Pennsylvania are Merlins seen most often?
By county, Schuylkill County, Perry County, and Mifflin County have the highest peak reporting rates for the Merlin (counties with at least 200 checklists).