WhenToBird

Falco columbarius · Falconidae

When Do Merlins Arrive in Connecticut?

Adult female Merlin
Photo: Cricket Raspet, CC BY 4.0 via iNaturalist

Merlins reach Connecticut in late August, are common by early September, peak in mid September (4.6% of checklists), and most are gone by mid November.

When to look

First arrivalsAug 22-31late August
Common bySep 1-7early September
PeakSep 15-21mid September
Most gone byNov 15-21mid November

Best: mid September. First arrivals late August; most are gone by mid November. Peak: on about 4.6% of Connecticut checklists.

  1. Januncommon
  2. Febuncommon
  3. Marrare
  4. Aprrare
  5. Mayrare
  6. Junnot usually seen
  7. Julrare
  8. Auguncommon
  9. Seppeak season
  10. Octpeak season
  11. Novcommon
  12. Decuncommon

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

0%2%4%6%Jan 1-7: 0.9% of 18950 checklistsJan 8-14: 1.0% of 13676 checklistsJan 15-21: 1.0% of 13377 checklistsJan 22-31: 1.2% of 17004 checklistsFeb 1-7: 1.0% of 10218 checklistsFeb 8-14: 0.8% of 11568 checklistsFeb 15-21: 0.5% of 15916 checklistsFeb 22-28: 0.8% of 11413 checklistsMar 1-7: 0.6% of 10754 checklistsMar 8-14: 0.6% of 12051 checklistsMar 15-21: 0.6% of 12616 checklistsMar 22-31: 0.7% of 17801 checklistsApr 1-7: 0.7% of 13186 checklistsApr 8-14: 0.5% of 14428 checklistsApr 15-21: 0.6% of 14738 checklistsApr 22-30: 0.6% of 21753 checklistsMay 1-7: 0.4% of 22494 checklistsMay 8-14: 0.3% of 23363 checklistsMay 15-21: 0.2% of 20219 checklistsMay 22-31: 0.1% of 20778 checklistsJun 1-7: 0% of 12234 checklistsJun 8-14: 0% of 12491 checklistsJun 15-21: 0.1% of 10856 checklistsJun 22-30: 0.1% of 11964 checklistsJul 1-7: 0% of 9437 checklistsJul 8-14: 0.1% of 8599 checklistsJul 15-21: 0.1% of 8252 checklistsJul 22-31: 0.2% of 11329 checklistsAug 1-7: 0.4% of 8116 checklistsAug 8-14: 0.2% of 8051 checklistsAug 15-21: 0.4% of 8502 checklistsAug 22-31: 1.2% of 13673 checklistsSep 1-7: 2.8% of 9873 checklistsSep 8-14: 4.4% of 9735 checklistsSep 15-21: 5.0% of 10120 checklistsSep 22-30: 4.4% of 12543 checklistsOct 1-7: 3.8% of 10735 checklistsOct 8-14: 4.3% of 10869 checklistsOct 15-21: 4.1% of 10436 checklistsOct 22-31: 3.3% of 13808 checklistsNov 1-7: 2.9% of 10507 checklistsNov 8-14: 2.0% of 9827 checklistsNov 15-21: 2.1% of 9904 checklistsNov 22-30: 1.3% of 13396 checklistsDec 1-7: 1.0% of 8974 checklistsDec 8-14: 1.1% of 9468 checklistsDec 15-21: 1.2% of 11614 checklistsDec 22-31: 1.0% 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. New Haven CountyBest the second week of October · 2651 checklists that week, 139,721 in all8.7%
  2. New London CountyBest mid September · 1000 checklists that week, 65,205 in all6.9%
  3. Windham CountyBest mid September · 267 checklists that week, 19,034 in all5.1%
  4. Fairfield CountyBest mid September · 2356 checklists that week, 139,848 in all4.9%
  5. Litchfield CountyBest the second week of September · 1119 checklists that week, 69,766 in all2.2%
  6. Middlesex CountyBest early October · 629 checklists that week, 39,919 in all2.0%

Best spots

Share of checklists at the peak
  1. Lighthouse PointNew Haven County, best mid October · 104 checklists that week, 2,239 in all50%
  2. Glastonbury MeadowsHartford County, best late October · 23 checklists that week, 683 in all30%
  3. Griswold CoveNew London County, best the second week of October · 31 checklists that week, 896 in all27%
  4. Trout Brook ValleyFairfield County, best early October · 52 checklists that week, 1,588 in all26%
  5. Hammonasset Natural Area PreserveNew Haven County, best the second week of October · 247 checklists that week, 10,098 in all23%
  6. Bluff PointNew London County, best mid September · 109 checklists that week, 770 in all23%

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

Best time of day

In Connecticut, the Merlin is most often listed on checklists started between 6 and 8 am (1.6% of those checklists).

0%0.5%1%1.5%2%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: 1.5% of 33657 checklists7 am: 1.6% of 62964 checklists8 am: 1.4% of 70645 checklists9 am: 1.2% of 64870 checklists10 am: 1.2% of 58827 checklists11 am: 1.0% of 51689 checklists12 pm: 0.9% of 45288 checklists1 pm: 1.0% of 44765 checklists2 pm: 1.1% of 44173 checklists3 pm: 1.1% of 41979 checklists4 pm: 1.1% of 33219 checklists5 pm: 0.9% of 24828 checklists6 pm: 0.6% 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
January0.9%1.0%1.0%1.2%
February1.0%0.8%0.5%0.8%
March0.6%0.6%0.6%0.7%
April0.7%0.5%0.6%0.6%
May0.4%0.3%0.2%0.1%
June0%0%0.1%0.1%
July0%0.1%0.1%0.2%
August0.4%0.2%0.4%1.2%
September2.8%4.4%5.0%4.4%
October3.8%4.3%4.1%3.3%
November2.9%2.0%2.1%1.3%
December1.0%1.1%1.2%1.0%

Neighboring states

  • Rhode Island: arrives late August, in the same week than Connecticut
  • Massachusetts: arrives the second week of August, 2 weeks earlier than Connecticut
  • New Jersey: arrives late August, in the same week than Connecticut
  • New York: arrives the second week of July, 6 weeks earlier than Connecticut

Common questions

When do Merlins arrive in Connecticut?
Merlins reach Connecticut in late August, are common by early September, peak in mid September (4.6% of checklists), and most are gone by mid November.
When do Merlins leave Connecticut?
Most Merlins have left Connecticut by mid November, when reports fall below half their usual rate. Stragglers are still reported until mid December.
When is the best time to see a Merlin in Connecticut?
The Merlin is reported most often in mid September, on about 4.6% of Connecticut checklists.
Where in Connecticut are Merlins seen most often?
By county, New Haven County, New London County, and Windham County have the highest peak reporting rates for the Merlin (counties with at least 200 checklists).