WhenToBird

Parkesia motacilla · Parulidae

When Do Louisiana Waterthrushes Arrive in Pennsylvania?

Adult Louisiana Waterthrush
Photo: Brian White, CC BY 4.0 via iNaturalist

Louisiana Waterthrushes arrive in Pennsylvania in early April, peak in late April (4.7% of checklists), and most are gone by early July.

When to look

First arrivalsApr 1-7early April
Common byApr 1-7early April
PeakApr 22-30late April
Most gone byJul 1-7early July

Best: late April. First arrivals early April; most are gone by early July. Peak: on about 4.7% of Pennsylvania checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Maruncommon
  4. Aprpeak season
  5. Maypeak season
  6. Juncommon
  7. Juluncommon
  8. Auguncommon
  9. Sepnot usually seen
  10. Octnot usually seen
  11. Novnot usually seen
  12. Decnot usually seen

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

0%2%4%6%Jan 1-7: 0% 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% of 42248 checklistsFeb 15-21: 0% of 55888 checklistsFeb 22-28: 0% of 42050 checklistsMar 1-7: 0% of 42709 checklistsMar 8-14: 0% of 43985 checklistsMar 15-21: 0.1% of 44547 checklistsMar 22-31: 0.4% of 66940 checklistsApr 1-7: 2.1% of 51147 checklistsApr 8-14: 3.9% of 54868 checklistsApr 15-21: 4.5% of 57252 checklistsApr 22-30: 4.9% of 81727 checklistsMay 1-7: 4.6% of 76472 checklistsMay 8-14: 4.1% of 79341 checklistsMay 15-21: 3.8% of 61724 checklistsMay 22-31: 3.2% of 70722 checklistsJun 1-7: 2.8% of 45652 checklistsJun 8-14: 2.8% of 41810 checklistsJun 15-21: 2.3% of 38973 checklistsJun 22-30: 1.9% of 44255 checklistsJul 1-7: 1.6% of 34822 checklistsJul 8-14: 1.5% of 31104 checklistsJul 15-21: 1.3% of 29262 checklistsJul 22-31: 1.4% of 41436 checklistsAug 1-7: 1.0% of 29189 checklistsAug 8-14: 0.6% of 28840 checklistsAug 15-21: 0.2% of 29948 checklistsAug 22-31: 0.1% of 48235 checklistsSep 1-7: 0.1% of 37175 checklistsSep 8-14: 0.1% of 36527 checklistsSep 15-21: 0% of 37261 checklistsSep 22-30: 0.1% of 43583 checklistsOct 1-7: 0% of 35352 checklistsOct 8-14: 0.1% of 35560 checklistsOct 15-21: 0% of 33119 checklistsOct 22-31: 0% of 44654 checklistsNov 1-7: 0% of 32965 checklistsNov 8-14: 0% of 31305 checklistsNov 15-21: 0% of 29471 checklistsNov 22-30: 0% of 38642 checklistsDec 1-7: 0% of 28779 checklistsDec 8-14: 0% of 29486 checklistsDec 15-21: 0% of 37465 checklistsDec 22-31: 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.

Embed this map on your site

Where in Pennsylvania

Best counties

Share of checklists at the peak
  1. Fayette CountyBest late April · 639 checklists that week, 15,396 in all16%
  2. Huntingdon CountyBest late April · 1547 checklists that week, 32,852 in all16%
  3. Blair CountyBest the second week of May · 449 checklists that week, 13,387 in all15%
  4. Greene CountyBest mid April · 84 checklists that week, 2,997 in all15%
  5. Perry CountyBest early May · 333 checklists that week, 10,281 in all14%
  6. Armstrong CountyBest mid April · 267 checklists that week, 11,221 in all12%

Best spots

Share of checklists at the peak
  1. Lower LakeMonroe County, best late April · 36 checklists that week, 1,218 in all89%
  2. Butler-Freeport Community TrailButler County, best mid April · 29 checklists that week, 324 in all88%
  3. Crouse RunAllegheny County, best late April · 26 checklists that week, 197 in all84%
  4. Fulshaw Craeg PreserveMontgomery County, best late April · 23 checklists that week, 240 in all83%
  5. Fall Run ParkAllegheny County, best early April · 21 checklists that week, 151 in all79%
  6. State Game Land 156Lancaster County, best mid April · 26 checklists that week, 601 in all79%

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

Best time of day

In Pennsylvania, the Louisiana Waterthrush is most often listed on checklists started between 6 and 8 am (2.3% of those checklists).

0%1%2%3%4%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: 3.2% of 92903 checklists7 am: 2.0% of 241233 checklists8 am: 1.7% of 271994 checklists9 am: 1.5% of 236842 checklists10 am: 1.3% of 199508 checklists11 am: 1.1% of 161893 checklists12 pm: 0.9% of 143945 checklists1 pm: 0.8% of 134352 checklists2 pm: 0.8% of 129692 checklists3 pm: 0.7% of 126132 checklists4 pm: 0.6% of 115055 checklists5 pm: 0.8% of 90719 checklists6 pm: 1.1% of 67534 checklists7 pm: 1.3% 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%0%0%0%
February0%0%0%0%
March0%0%0.1%0.4%
April2.1%3.9%4.5%4.9%
May4.6%4.1%3.8%3.2%
June2.8%2.8%2.3%1.9%
July1.6%1.5%1.3%1.4%
August1.0%0.6%0.2%0.1%
September0.1%0.1%0%0.1%
October0%0.1%0%0%
November0%0%0%0%
December0%0%0%0%

Neighboring states

  • Maryland: arrives late March, 1 week earlier than Pennsylvania
  • District of Columbia: arrives late March, 1 week earlier than Pennsylvania
  • Delaware: arrives late March, 1 week earlier than Pennsylvania
  • New Jersey: arrives early April, in the same week than Pennsylvania

Common questions

When do Louisiana Waterthrushes arrive in Pennsylvania?
Louisiana Waterthrushes arrive in Pennsylvania in early April, peak in late April (4.7% of checklists), and most are gone by early July.
When do Louisiana Waterthrushes leave Pennsylvania?
Most Louisiana Waterthrushes have left Pennsylvania by early July, when reports fall below half their usual rate. Stragglers are still reported until early August.
When is the best time to see a Louisiana Waterthrush in Pennsylvania?
The Louisiana Waterthrush is reported most often in late April, on about 4.7% of Pennsylvania checklists.
Where in Pennsylvania are Louisiana Waterthrushes seen most often?
By county, Fayette County, Huntingdon County, and Blair County have the highest peak reporting rates for the Louisiana Waterthrush (counties with at least 200 checklists).