WhenToBird

Cistothorus palustris · Troglodytidae

When Do Marsh Wrens Arrive in Maryland?

Adult Marsh Wren
Photo: Kathy Richardson, CC BY 4.0 via iNaturalist

Marsh Wrens arrive in Maryland in the second week of April, peak in late April (1.3% of checklists), and most are gone by the second week of August.

When to look

First arrivalsApr 8-14the second week of April
Common byApr 8-14the second week of April
PeakApr 22-30late April
Most gone byAug 8-14the second week of August

Best: late April. First arrivals the second week of April; most are gone by the second week of August. Peak: on about 1.3% of Maryland checklists.

  1. Januncommon
  2. Febrare
  3. Maruncommon
  4. Aprpeak season
  5. Maypeak season
  6. Junpeak season
  7. Julpeak season
  8. Augpeak season
  9. Sepcommon
  10. Octpeak season
  11. Novcommon
  12. Decuncommon

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

0%0.5%1%1.5%Jan 1-7: 0.3% of 28716 checklistsJan 8-14: 0.2% of 21449 checklistsJan 15-21: 0.1% of 21267 checklistsJan 22-31: 0.2% of 29144 checklistsFeb 1-7: 0.1% of 21347 checklistsFeb 8-14: 0.1% of 22166 checklistsFeb 15-21: 0.1% of 29986 checklistsFeb 22-28: 0.1% of 22427 checklistsMar 1-7: 0.1% of 21389 checklistsMar 8-14: 0.2% of 22192 checklistsMar 15-21: 0.3% of 22823 checklistsMar 22-31: 0.2% of 33720 checklistsApr 1-7: 0.3% of 25513 checklistsApr 8-14: 0.5% of 27718 checklistsApr 15-21: 0.9% of 29328 checklistsApr 22-30: 1.5% of 42595 checklistsMay 1-7: 1.3% of 38532 checklistsMay 8-14: 1.0% of 42722 checklistsMay 15-21: 0.9% of 31936 checklistsMay 22-31: 0.9% of 36903 checklistsJun 1-7: 1.1% of 23191 checklistsJun 8-14: 1.1% of 21853 checklistsJun 15-21: 1.2% of 21000 checklistsJun 22-30: 1.1% of 25133 checklistsJul 1-7: 1.2% of 18715 checklistsJul 8-14: 1.3% of 16376 checklistsJul 15-21: 1.0% of 15793 checklistsJul 22-31: 1.2% of 21969 checklistsAug 1-7: 0.9% of 16013 checklistsAug 8-14: 0.6% of 15249 checklistsAug 15-21: 0.2% of 15674 checklistsAug 22-31: 0.4% of 24925 checklistsSep 1-7: 0.4% of 19808 checklistsSep 8-14: 0.5% of 18513 checklistsSep 15-21: 0.8% of 21901 checklistsSep 22-30: 0.8% of 22901 checklistsOct 1-7: 1.0% of 19111 checklistsOct 8-14: 1.1% of 18482 checklistsOct 15-21: 0.8% of 17380 checklistsOct 22-31: 0.8% of 23992 checklistsNov 1-7: 0.7% of 17915 checklistsNov 8-14: 0.7% of 18905 checklistsNov 15-21: 0.5% of 16259 checklistsNov 22-30: 0.4% of 22852 checklistsDec 1-7: 0.3% of 16108 checklistsDec 8-14: 0.3% of 16512 checklistsDec 15-21: 0.2% of 18952 checklistsDec 22-31: 0.6% of 29728 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 Maryland 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 Maryland

Best counties

Share of checklists at the peak
  1. Somerset CountyBest late July · 196 checklists that week, 9,451 in all31%
  2. Dorchester CountyBest the second week of July · 327 checklists that week, 26,161 in all20%
  3. St. Mary's CountyBest early October · 275 checklists that week, 20,572 in all3.5%
  4. Wicomico CountyBest the second week of July · 258 checklists that week, 12,356 in all2.9%
  5. Calvert CountyBest early May · 1163 checklists that week, 43,807 in all2.3%
  6. Prince George's CountyBest mid July · 1162 checklists that week, 87,907 in all2.0%

Best spots

Share of checklists at the peak
  1. Dames Quarter MarshSomerset County, best late June · 21 checklists that week, 694 in all95%
  2. Rumbly PointSomerset County, best late May · 20 checklists that week, 412 in all90%
  3. Fairmount WmaSomerset County, best late December · 24 checklists that week, 123 in all75%
  4. Deal Island WmaSomerset County, best late April · 23 checklists that week, 505 in all65%
  5. Chesapeake Beach Railway TrailCalvert County, best the second week of May · 27 checklists that week, 986 in all56%
  6. Franklin Point State ParkAnne Arundel County, best early May · 30 checklists that week, 363 in all43%

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

Best time of day

In Maryland, the Marsh Wren is most often listed on checklists started between 6 and 8 am (0.9% of those checklists).

0%0.5%1%1.5%12 am: too few checklists (486) to judge1 am: too few checklists (451) to judge2 am: too few checklists (447) to judge3 am: too few checklists (766) to judge4 am: too few checklists (2076) to judge5 am: too few checklists (11098) to judge6 am: 1.3% of 56604 checklists7 am: 0.8% of 139255 checklists8 am: 0.6% of 148626 checklists9 am: 0.6% of 126820 checklists10 am: 0.6% of 106973 checklists11 am: 0.5% of 87483 checklists12 pm: 0.5% of 74808 checklists1 pm: 0.4% of 69428 checklists2 pm: 0.4% of 67800 checklists3 pm: 0.5% of 67688 checklists4 pm: 0.5% of 60927 checklists5 pm: 0.6% of 43876 checklists6 pm: 0.7% of 32930 checklists7 pm: too few checklists (19051) to judge8 pm: too few checklists (5708) to judge9 pm: too few checklists (1977) to judge10 pm: too few checklists (1170) to judge11 pm: too few checklists (635) 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
January0.3%0.2%0.1%0.2%
February0.1%0.1%0.1%0.1%
March0.1%0.2%0.3%0.2%
April0.3%0.5%0.9%1.5%
May1.3%1.0%0.9%0.9%
June1.1%1.1%1.2%1.1%
July1.2%1.3%1.0%1.2%
August0.9%0.6%0.2%0.4%
September0.4%0.5%0.8%0.8%
October1.0%1.1%0.8%0.8%
November0.7%0.7%0.5%0.4%
December0.3%0.3%0.2%0.6%

Neighboring states

  • District of Columbia: arrives the second week of September, 20 weeks later than Maryland
  • Delaware: arrives the second week of April, in the same week than Maryland
  • Virginia: arrives the second week of September, 20 weeks later than Maryland
  • Pennsylvania: arrives late April, 2 weeks later than Maryland

Common questions

When do Marsh Wrens arrive in Maryland?
Marsh Wrens arrive in Maryland in the second week of April, peak in late April (1.3% of checklists), and most are gone by the second week of August.
When do Marsh Wrens leave Maryland?
Most Marsh Wrens have left Maryland by the second week of August, when reports fall below half their usual rate.
When is the best time to see a Marsh Wren in Maryland?
The Marsh Wren is reported most often in late April, on about 1.3% of Maryland checklists.
Where in Maryland are Marsh Wrens seen most often?
By county, Somerset County, Dorchester County, and St. Mary's County have the highest peak reporting rates for the Marsh Wren (counties with at least 200 checklists).