WhenToBird

Toxostoma rufum · Mimidae

When Do Brown Thrashers Arrive in Pennsylvania?

Adult Brown Thrasher
Photo: northerly, CC BY 4.0 via iNaturalist

Brown Thrashers reach Pennsylvania in late March, are common by early April, peak in late April (12% of checklists), and most are gone by late September.

When to look

First arrivalsMar 22-31late March
Common byApr 1-7early April
PeakApr 22-30late April
Most gone bySep 22-30late September

Best: late April. First arrivals late March; most are gone by late September. Peak: on about 12% of Pennsylvania checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Maruncommon
  4. Aprpeak season
  5. Maypeak season
  6. Junpeak season
  7. Julcommon
  8. Auguncommon
  9. Sepcommon
  10. Octuncommon
  11. Novnot usually seen
  12. Decnot usually seen

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

0%5%10%15%Jan 1-7: 0.1% of 47145 checklistsJan 8-14: 0.1% of 35840 checklistsJan 15-21: 0.1% of 35423 checklistsJan 22-31: 0.1% of 49126 checklistsFeb 1-7: 0.1% of 36366 checklistsFeb 8-14: 0.1% of 42248 checklistsFeb 15-21: 0.1% of 55888 checklistsFeb 22-28: 0.1% of 42050 checklistsMar 1-7: 0.1% of 42709 checklistsMar 8-14: 0.1% of 43985 checklistsMar 15-21: 0.1% of 44547 checklistsMar 22-31: 1.0% of 66940 checklistsApr 1-7: 4.7% of 51147 checklistsApr 8-14: 9.9% of 54868 checklistsApr 15-21: 13% of 57252 checklistsApr 22-30: 13% of 81727 checklistsMay 1-7: 12% of 76472 checklistsMay 8-14: 11% of 79341 checklistsMay 15-21: 11% of 61724 checklistsMay 22-31: 10% of 70722 checklistsJun 1-7: 9.4% of 45652 checklistsJun 8-14: 8.6% of 41810 checklistsJun 15-21: 8.5% of 38973 checklistsJun 22-30: 8.2% of 44255 checklistsJul 1-7: 7.8% of 34822 checklistsJul 8-14: 6.5% of 31104 checklistsJul 15-21: 5.2% of 29262 checklistsJul 22-31: 4.1% of 41436 checklistsAug 1-7: 3.3% of 29189 checklistsAug 8-14: 2.7% of 28840 checklistsAug 15-21: 2.8% of 29948 checklistsAug 22-31: 3.3% of 48235 checklistsSep 1-7: 4.7% of 37175 checklistsSep 8-14: 6.1% of 36527 checklistsSep 15-21: 6.7% of 37261 checklistsSep 22-30: 4.9% of 43583 checklistsOct 1-7: 2.9% of 35352 checklistsOct 8-14: 1.2% of 35560 checklistsOct 15-21: 0.7% of 33119 checklistsOct 22-31: 0.5% of 44654 checklistsNov 1-7: 0.2% of 32965 checklistsNov 8-14: 0.2% of 31305 checklistsNov 15-21: 0.2% of 29471 checklistsNov 22-30: 0.1% of 38642 checklistsDec 1-7: 0.1% of 28779 checklistsDec 8-14: 0.1% of 29486 checklistsDec 15-21: 0.1% of 37465 checklistsDec 22-31: 0.1% 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. Montour CountyBest late April · 304 checklists that week, 6,082 in all41%
  2. Juniata CountyBest late April · 408 checklists that week, 9,807 in all33%
  3. Lycoming CountyBest late April · 1150 checklists that week, 29,685 in all31%
  4. Clarion CountyBest late April · 314 checklists that week, 9,153 in all28%
  5. Union CountyBest late April · 307 checklists that week, 7,238 in all26%
  6. Bedford CountyBest the second week of July · 179 checklists that week, 11,483 in all25%

Best spots

Share of checklists at the peak
  1. Hall PondLycoming County, best mid May · 37 checklists that week, 1,740 in all82%
  2. State Game Land 145Lebanon County, best late June · 24 checklists that week, 1,030 in all77%
  3. Armstrong Open SpaceLycoming County, best late April · 32 checklists that week, 554 in all73%
  4. High Bridge CreekSusquehanna County, best early July · 20 checklists that week, 1,092 in all72%
  5. Memorial Lake State ParkLebanon County, best late May · 77 checklists that week, 3,533 in all68%

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

Best time of day

In Pennsylvania, the Brown Thrasher is most often listed on checklists started between 6 and 8 am (8.3% of those checklists).

0%5%10%15%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: 10% of 92903 checklists7 am: 7.5% of 241233 checklists8 am: 6.0% of 271994 checklists9 am: 4.6% of 236842 checklists10 am: 3.7% of 199508 checklists11 am: 3.1% of 161893 checklists12 pm: 2.7% of 143945 checklists1 pm: 2.7% of 134352 checklists2 pm: 2.5% of 129692 checklists3 pm: 2.5% of 126132 checklists4 pm: 2.9% of 115055 checklists5 pm: 4.1% of 90719 checklists6 pm: 4.7% of 67534 checklists7 pm: 4.3% 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
January0.1%0.1%0.1%0.1%
February0.1%0.1%0.1%0.1%
March0.1%0.1%0.1%1.0%
April4.7%9.9%13%13%
May12%11%11%10%
June9.4%8.6%8.5%8.2%
July7.8%6.5%5.2%4.1%
August3.3%2.7%2.8%3.3%
September4.7%6.1%6.7%4.9%
October2.9%1.2%0.7%0.5%
November0.2%0.2%0.2%0.1%
December0.1%0.1%0.1%0.1%

Neighboring states

  • Maryland: arrives the second week of March, 2 weeks earlier than Pennsylvania
  • District of Columbia: arrives early March, 3 weeks earlier than Pennsylvania
  • Delaware: arrives mid March, 1 week earlier than Pennsylvania
  • New Jersey: arrives mid March, 1 week earlier than Pennsylvania

Common questions

When do Brown Thrashers arrive in Pennsylvania?
Brown Thrashers reach Pennsylvania in late March, are common by early April, peak in late April (12% of checklists), and most are gone by late September.
When do Brown Thrashers leave Pennsylvania?
Most Brown Thrashers have left Pennsylvania by late September, when reports fall below half their usual rate. Stragglers are still reported until the second week of October.
When is the best time to see a Brown Thrasher in Pennsylvania?
The Brown Thrasher is reported most often in late April, on about 12% of Pennsylvania checklists.
Where in Pennsylvania are Brown Thrashers seen most often?
By county, Montour County, Juniata County, and Lycoming County have the highest peak reporting rates for the Brown Thrasher (counties with at least 200 checklists).