WhenToBird

Vireo solitarius · Vireonidae

When Do Blue-headed Vireos Arrive in Pennsylvania?

Adult Blue-headed Vireo
Photo: Gordon Johnston, CC BY-SA 4.0 via iNaturalist

Blue-headed Vireos are winter birds in Pennsylvania: they arrive in the second week of April, peak in the second week of October (8.0% of checklists), and most are gone by late October.

When to look

First arrivalsApr 8-14the second week of April
Common byApr 8-14the second week of April
PeakOct 8-14the second week of October
Most gone byOct 22-31late October

Best: the second week of October. First arrivals the second week of April; most are gone by late October. Peak: on about 8.0% of Pennsylvania checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Marnot usually seen
  4. Aprpeak season
  5. Maypeak season
  6. Juncommon
  7. Julcommon
  8. Auguncommon
  9. Sepcommon
  10. Octpeak season
  11. Novuncommon
  12. Decnot usually seen

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

0%5%10%Jan 1-7: 0.1% of 47145 checklistsJan 8-14: 0% of 35840 checklistsJan 15-21: 0% of 35423 checklistsJan 22-31: 0% of 49126 checklistsFeb 1-7: 0% of 36366 checklistsFeb 8-14: 0.1% of 42248 checklistsFeb 15-21: 0% of 55888 checklistsFeb 22-28: 0% of 42050 checklistsMar 1-7: 0% of 42709 checklistsMar 8-14: 0.1% of 43985 checklistsMar 15-21: 0% of 44547 checklistsMar 22-31: 0.1% of 66940 checklistsApr 1-7: 0.3% of 51147 checklistsApr 8-14: 1.8% of 54868 checklistsApr 15-21: 5.0% of 57252 checklistsApr 22-30: 8.4% of 81727 checklistsMay 1-7: 8.6% of 76472 checklistsMay 8-14: 6.6% of 79341 checklistsMay 15-21: 4.9% of 61724 checklistsMay 22-31: 3.8% of 70722 checklistsJun 1-7: 3.4% of 45652 checklistsJun 8-14: 4.2% of 41810 checklistsJun 15-21: 4.4% of 38973 checklistsJun 22-30: 4.3% of 44255 checklistsJul 1-7: 4.1% of 34822 checklistsJul 8-14: 3.7% of 31104 checklistsJul 15-21: 3.1% of 29262 checklistsJul 22-31: 2.4% of 41436 checklistsAug 1-7: 1.7% of 29189 checklistsAug 8-14: 1.2% of 28840 checklistsAug 15-21: 1.0% of 29948 checklistsAug 22-31: 1.1% of 48235 checklistsSep 1-7: 1.4% of 37175 checklistsSep 8-14: 1.8% of 36527 checklistsSep 15-21: 3.4% of 37261 checklistsSep 22-30: 5.5% of 43583 checklistsOct 1-7: 8.0% of 35352 checklistsOct 8-14: 8.7% of 35560 checklistsOct 15-21: 7.2% of 33119 checklistsOct 22-31: 2.5% of 44654 checklistsNov 1-7: 0.5% of 32965 checklistsNov 8-14: 0.1% of 31305 checklistsNov 15-21: 0.1% 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. Elk CountyBest late May · 292 checklists that week, 6,751 in all37%
  2. Warren CountyBest late April · 218 checklists that week, 5,449 in all34%
  3. Forest CountyBest the second week of June · 117 checklists that week, 5,388 in all30%
  4. Sullivan CountyBest the second week of June · 170 checklists that week, 4,362 in all29%
  5. Wyoming CountyBest the second week of July · 103 checklists that week, 6,156 in all27%
  6. Cameron CountyBest late April · 171 checklists that week, 5,057 in all22%

Best spots

Share of checklists at the peak
  1. Lower LakeMonroe County, best late April · 36 checklists that week, 1,218 in all84%
  2. Locust Lake State ParkSchuylkill County, best early May · 51 checklists that week, 919 in all71%
  3. Tumbling Run Reservoir Number TwoSchuylkill County, best early May · 20 checklists that week, 190 in all69%
  4. State Game Land 035Susquehanna County, best early May · 22 checklists that week, 729 in all65%
  5. Raymond B. Winter State ParkUnion County, best the second week of May · 34 checklists that week, 556 in all58%

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

Best time of day

In Pennsylvania, the Blue-headed Vireo is most often listed on checklists started between 6 and 8 am (4.5% of those checklists).

0%2%4%6%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: 5.1% of 92903 checklists7 am: 4.2% of 241233 checklists8 am: 3.8% of 271994 checklists9 am: 3.1% of 236842 checklists10 am: 2.7% of 199508 checklists11 am: 2.2% of 161893 checklists12 pm: 2.0% of 143945 checklists1 pm: 1.7% of 134352 checklists2 pm: 1.7% of 129692 checklists3 pm: 1.5% of 126132 checklists4 pm: 1.5% of 115055 checklists5 pm: 1.4% of 90719 checklists6 pm: 1.1% of 67534 checklists7 pm: 0.7% 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%0%0%
February0%0.1%0%0%
March0%0.1%0%0.1%
April0.3%1.8%5.0%8.4%
May8.6%6.6%4.9%3.8%
June3.4%4.2%4.4%4.3%
July4.1%3.7%3.1%2.4%
August1.7%1.2%1.0%1.1%
September1.4%1.8%3.4%5.5%
October8.0%8.7%7.2%2.5%
November0.5%0.1%0.1%0.1%
December0.1%0.1%0.1%0.1%

Neighboring states

  • Maryland: arrives the second week of September, 20 weeks later than Pennsylvania
  • District of Columbia: arrives early April, 1 week earlier than Pennsylvania
  • Delaware: arrives early September, 19 weeks later than Pennsylvania
  • New Jersey: arrives the second week of April, in the same week than Pennsylvania

Common questions

When do Blue-headed Vireos arrive in Pennsylvania?
Blue-headed Vireos are winter birds in Pennsylvania: they arrive in the second week of April, peak in the second week of October (8.0% of checklists), and most are gone by late October.
When do Blue-headed Vireos leave Pennsylvania?
Most Blue-headed Vireos have left Pennsylvania by late October, when reports fall below half their usual rate. Stragglers are still reported until early November.
When is the best time to see a Blue-headed Vireo in Pennsylvania?
The Blue-headed Vireo is reported most often in the second week of October, on about 8.0% of Pennsylvania checklists.
Where in Pennsylvania are Blue-headed Vireos seen most often?
By county, Elk County, Warren County, and Forest County have the highest peak reporting rates for the Blue-headed Vireo (counties with at least 200 checklists).