WhenToBird

Mniotilta varia · Parulidae

When Do Black-and-white Warblers Arrive in Connecticut?

Adult female Black-and-white Warbler
Photo: Donald Davesne, CC BY 4.0 via iNaturalist

Black-and-white Warblers arrive in Connecticut in mid April, peak in the second week of May (28% of checklists), and most are gone by early October.

When to look

First arrivalsApr 15-21mid April
Common byApr 15-21mid April
PeakMay 8-14the second week of May
Most gone byOct 1-7early October

Best: the second week of May. First arrivals mid April; most are gone by early October. Peak: on about 28% of Connecticut checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Marnot usually seen
  4. Aprcommon
  5. Maypeak season
  6. Jununcommon
  7. Juluncommon
  8. Auguncommon
  9. Sepcommon
  10. Octuncommon
  11. Novnot usually seen
  12. Decnot usually seen

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

0%10%20%30%40%Jan 1-7: 0% of 18950 checklistsJan 8-14: 0.1% of 13676 checklistsJan 15-21: 0% of 13377 checklistsJan 22-31: 0.1% of 17004 checklistsFeb 1-7: 0% of 10218 checklistsFeb 8-14: 0% of 11568 checklistsFeb 15-21: 0% of 15916 checklistsFeb 22-28: 0% of 11413 checklistsMar 1-7: 0% of 10754 checklistsMar 8-14: 0% of 12051 checklistsMar 15-21: 0% of 12616 checklistsMar 22-31: 0% of 17801 checklistsApr 1-7: 0.1% of 13186 checklistsApr 8-14: 0.1% of 14428 checklistsApr 15-21: 0.9% of 14738 checklistsApr 22-30: 13% of 21753 checklistsMay 1-7: 30% of 22494 checklistsMay 8-14: 30% of 23363 checklistsMay 15-21: 22% of 20219 checklistsMay 22-31: 12% of 20778 checklistsJun 1-7: 8.7% of 12234 checklistsJun 8-14: 8.8% of 12491 checklistsJun 15-21: 8.6% of 10856 checklistsJun 22-30: 7.2% of 11964 checklistsJul 1-7: 5.2% of 9437 checklistsJul 8-14: 4.5% of 8599 checklistsJul 15-21: 3.9% of 8252 checklistsJul 22-31: 3.8% of 11329 checklistsAug 1-7: 4.5% of 8116 checklistsAug 8-14: 4.4% of 8051 checklistsAug 15-21: 4.9% of 8502 checklistsAug 22-31: 8.2% of 13673 checklistsSep 1-7: 7.9% of 9873 checklistsSep 8-14: 13% of 9735 checklistsSep 15-21: 13% of 10120 checklistsSep 22-30: 12% of 12543 checklistsOct 1-7: 5.6% of 10735 checklistsOct 8-14: 1.9% of 10869 checklistsOct 15-21: 0.4% of 10436 checklistsOct 22-31: 0.2% of 13808 checklistsNov 1-7: 0.1% of 10507 checklistsNov 8-14: 0.1% of 9827 checklistsNov 15-21: 0.1% of 9904 checklistsNov 22-30: 0.1% of 13396 checklistsDec 1-7: 0.1% of 8974 checklistsDec 8-14: 0.1% of 9468 checklistsDec 15-21: 0.1% of 11614 checklistsDec 22-31: 0% 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. Litchfield CountyBest the second week of May · 2528 checklists that week, 69,766 in all38%
  2. Windham CountyBest the second week of May · 930 checklists that week, 19,034 in all35%
  3. New Haven CountyBest the second week of May · 5629 checklists that week, 139,721 in all31%
  4. Fairfield CountyBest the second week of May · 4844 checklists that week, 139,848 in all28%
  5. Tolland CountyBest the second week of May · 1577 checklists that week, 39,004 in all24%
  6. Hartford CountyBest the second week of May · 4171 checklists that week, 105,735 in all23%

Best spots

Share of checklists at the peak
  1. Appalachian National Scenic TrailLitchfield County, best early May · 34 checklists that week, 308 in all88%
  2. Bluff PointNew London County, best mid September · 109 checklists that week, 770 in all85%
  3. Penwood State ParkHartford County, best the second week of May · 26 checklists that week, 192 in all78%
  4. Yale ForestWindham County, best the second week of May · 43 checklists that week, 327 in all77%
  5. Trout Brook ValleyFairfield County, best the second week of May · 102 checklists that week, 1,588 in all74%

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

Best time of day

In Connecticut, the Black-and-white Warbler is most often listed on checklists started between 6 and 8 am (11% of those checklists).

0%5%10%15%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: 14% of 33657 checklists7 am: 9.6% of 62964 checklists8 am: 8.1% of 70645 checklists9 am: 6.1% of 64870 checklists10 am: 4.8% of 58827 checklists11 am: 3.9% of 51689 checklists12 pm: 3.7% of 45288 checklists1 pm: 3.6% of 44765 checklists2 pm: 3.5% of 44173 checklists3 pm: 3.7% of 41979 checklists4 pm: 4.7% of 33219 checklists5 pm: 5.7% of 24828 checklists6 pm: 5.6% 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%0.1%0%0.1%
February0%0%0%0%
March0%0%0%0%
April0.1%0.1%0.9%13%
May30%30%22%12%
June8.7%8.8%8.6%7.2%
July5.2%4.5%3.9%3.8%
August4.5%4.4%4.9%8.2%
September7.9%13%13%12%
October5.6%1.9%0.4%0.2%
November0.1%0.1%0.1%0.1%
December0.1%0.1%0.1%0%

Neighboring states

  • Rhode Island: arrives mid April, in the same week than Connecticut
  • Massachusetts: arrives mid April, in the same week than Connecticut
  • New Jersey: arrives the second week of April, 1 week earlier than Connecticut
  • New York: arrives mid April, in the same week than Connecticut

Common questions

When do Black-and-white Warblers arrive in Connecticut?
Black-and-white Warblers arrive in Connecticut in mid April, peak in the second week of May (28% of checklists), and most are gone by early October.
When do Black-and-white Warblers leave Connecticut?
Most Black-and-white Warblers have left Connecticut by early October, 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 Black-and-white Warbler in Connecticut?
The Black-and-white Warbler is reported most often in the second week of May, on about 28% of Connecticut checklists.
Where in Connecticut are Black-and-white Warblers seen most often?
By county, Litchfield County, Windham County, and New Haven County have the highest peak reporting rates for the Black-and-white Warbler (counties with at least 200 checklists).