WhenToBird

Cistothorus palustris · Troglodytidae

When Do Marsh Wrens Arrive in Connecticut?

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

Marsh Wrens reach Connecticut in late April, are common by early May, peak in mid July (6.3% of checklists), and most are gone by late September.

When to look

First arrivalsApr 22-30late April
Common byMay 1-7early May
PeakJul 15-21mid July
Most gone bySep 22-30late September

Best: mid July. First arrivals late April; most are gone by late September. Peak: on about 6.3% of Connecticut checklists.

  1. Janrare
  2. Febnot usually seen
  3. Marnot usually seen
  4. Apruncommon
  5. Maypeak season
  6. Junpeak season
  7. Julpeak season
  8. Augcommon
  9. Sepcommon
  10. Octuncommon
  11. Novrare
  12. Decrare

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

0%2%4%6%8%Jan 1-7: 0.3% of 18950 checklistsJan 8-14: 0.2% of 13676 checklistsJan 15-21: 0.1% of 13377 checklistsJan 22-31: 0.2% of 17004 checklistsFeb 1-7: 0.3% of 10218 checklistsFeb 8-14: 0.2% of 11568 checklistsFeb 15-21: 0.1% of 15916 checklistsFeb 22-28: 0.1% of 11413 checklistsMar 1-7: 0.1% of 10754 checklistsMar 8-14: 0.1% of 12051 checklistsMar 15-21: 0.1% of 12616 checklistsMar 22-31: 0.1% of 17801 checklistsApr 1-7: 0.3% of 13186 checklistsApr 8-14: 0.3% of 14428 checklistsApr 15-21: 0.7% of 14738 checklistsApr 22-30: 1.3% of 21753 checklistsMay 1-7: 2.5% of 22494 checklistsMay 8-14: 3.8% of 23363 checklistsMay 15-21: 5.7% of 20219 checklistsMay 22-31: 6.4% of 20778 checklistsJun 1-7: 5.7% of 12234 checklistsJun 8-14: 4.9% of 12491 checklistsJun 15-21: 4.9% of 10856 checklistsJun 22-30: 4.8% of 11964 checklistsJul 1-7: 5.5% of 9437 checklistsJul 8-14: 6.2% of 8599 checklistsJul 15-21: 6.7% of 8252 checklistsJul 22-31: 6.3% of 11329 checklistsAug 1-7: 4.2% of 8116 checklistsAug 8-14: 2.9% of 8051 checklistsAug 15-21: 2.1% of 8502 checklistsAug 22-31: 2.1% of 13673 checklistsSep 1-7: 2.7% of 9873 checklistsSep 8-14: 2.8% of 9735 checklistsSep 15-21: 2.8% of 10120 checklistsSep 22-30: 2.6% of 12543 checklistsOct 1-7: 2.1% of 10735 checklistsOct 8-14: 1.5% of 10869 checklistsOct 15-21: 0.9% of 10436 checklistsOct 22-31: 0.7% of 13808 checklistsNov 1-7: 0.5% of 10507 checklistsNov 8-14: 0.3% of 9827 checklistsNov 15-21: 0.4% of 9904 checklistsNov 22-30: 0.2% of 13396 checklistsDec 1-7: 0.2% of 8974 checklistsDec 8-14: 0.4% of 9468 checklistsDec 15-21: 0.3% of 11614 checklistsDec 22-31: 0.2% of 16616 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 Connecticut 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 Connecticut

Best counties

Share of checklists at the peak
  1. New Haven CountyBest mid July · 1766 checklists that week, 139,721 in all13%
  2. Litchfield CountyBest late May · 2808 checklists that week, 69,766 in all7.5%
  3. New London CountyBest early June · 1169 checklists that week, 65,205 in all6.6%
  4. Middlesex CountyBest mid July · 474 checklists that week, 39,919 in all6.6%
  5. Fairfield CountyBest early June · 2304 checklists that week, 139,848 in all6.3%
  6. Hartford CountyBest the second week of July · 1412 checklists that week, 105,735 in all1.9%

Best spots

Share of checklists at the peak
  1. Stewart B. Mckinney National Wildlife Refuge (Lewis Gut)Fairfield County, best mid June · 21 checklists that week, 1,029 in all92%
  2. White Memorial Foundation, Inc.Litchfield County, best early June · 113 checklists that week, 3,047 in all91%
  3. Ragged Rock Creek Marsh Wildlife AreaMiddlesex County, best the second week of May · 26 checklists that week, 134 in all85%
  4. Hammonasset Natural Area Preserve (Willard Island)New Haven County, best early June · 23 checklists that week, 1,363 in all76%
  5. Hammonasset Natural Area PreserveNew Haven County, best the second week of July · 134 checklists that week, 10,098 in all75%
  6. Sherwood Island State ParkFairfield County, best mid July · 70 checklists that week, 6,315 in all68%

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

Best time of day

In Connecticut, the Marsh Wren is most often listed on checklists started between 6 and 8 am (2.9% of those checklists).

0%1%2%3%4%12 am: too few checklists (325) to judge1 am: too few checklists (367) to judge2 am: too few checklists (488) to judge3 am: too few checklists (792) to judge4 am: too few checklists (2722) to judge5 am: too few checklists (9489) to judge6 am: 3.9% of 33657 checklists7 am: 2.3% of 62964 checklists8 am: 2.8% of 70645 checklists9 am: 2.1% of 64870 checklists10 am: 1.8% of 58827 checklists11 am: 1.5% of 51689 checklists12 pm: 1.3% of 45288 checklists1 pm: 1.3% of 44765 checklists2 pm: 1.3% of 44173 checklists3 pm: 1.3% of 41979 checklists4 pm: 1.5% of 33219 checklists5 pm: 1.7% of 24828 checklists6 pm: 2.2% of 15856 checklists7 pm: too few checklists (8126) to judge8 pm: too few checklists (1994) to judge9 pm: too few checklists (533) to judge10 pm: too few checklists (349) to judge11 pm: too few checklists (286) 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%
February0.3%0.2%0.1%0.1%
March0.1%0.1%0.1%0.1%
April0.3%0.3%0.7%1.3%
May2.5%3.8%5.7%6.4%
June5.7%4.9%4.9%4.8%
July5.5%6.2%6.7%6.3%
August4.2%2.9%2.1%2.1%
September2.7%2.8%2.8%2.6%
October2.1%1.5%0.9%0.7%
November0.5%0.3%0.4%0.2%
December0.2%0.4%0.3%0.2%

Neighboring states

  • Rhode Island: arrives early April, 3 weeks earlier than Connecticut
  • Massachusetts: arrives late April, in the same week than Connecticut
  • New Jersey: arrives mid April, 1 week earlier than Connecticut
  • New York: arrives late April, in the same week than Connecticut

Common questions

When do Marsh Wrens arrive in Connecticut?
Marsh Wrens reach Connecticut in late April, are common by early May, peak in mid July (6.3% of checklists), and most are gone by late September.
When do Marsh Wrens leave Connecticut?
Most Marsh Wrens have left Connecticut by late September, when reports fall below half their usual rate. Stragglers are still reported until mid October.
When is the best time to see a Marsh Wren in Connecticut?
The Marsh Wren is reported most often in mid July, on about 6.3% of Connecticut checklists.
Where in Connecticut are Marsh Wrens seen most often?
By county, New Haven County, Litchfield County, and New London County have the highest peak reporting rates for the Marsh Wren (counties with at least 200 checklists).