WhenToBird

Falco columbarius · Falconidae

When Do Merlins Arrive in Massachusetts?

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

Merlins arrive in Massachusetts in the second week of August, peak in mid September (3.1% of checklists), and most are gone by early March.

When to look

First arrivalsAug 8-14the second week of August
Common byAug 8-14the second week of August
PeakSep 15-21mid September
Most gone byMar 1-7early March

Best: mid September. First arrivals the second week of August; most are gone by early March. Peak: on about 3.1% of Massachusetts checklists.

  1. Jancommon
  2. Febuncommon
  3. Maruncommon
  4. Apruncommon
  5. Mayuncommon
  6. Junrare
  7. Julrare
  8. Augcommon
  9. Seppeak season
  10. Octpeak season
  11. Novcommon
  12. Deccommon

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

0%1%2%3%4%Jan 1-7: 1.2% of 43252 checklistsJan 8-14: 1.1% of 30096 checklistsJan 15-21: 1.0% of 28760 checklistsJan 22-31: 1.1% of 38135 checklistsFeb 1-7: 1.1% of 26442 checklistsFeb 8-14: 1.0% of 29034 checklistsFeb 15-21: 0.6% of 37383 checklistsFeb 22-28: 0.8% of 29977 checklistsMar 1-7: 0.7% of 29175 checklistsMar 8-14: 0.5% of 32399 checklistsMar 15-21: 0.5% of 34444 checklistsMar 22-31: 0.7% of 49126 checklistsApr 1-7: 0.8% of 36456 checklistsApr 8-14: 0.8% of 40908 checklistsApr 15-21: 0.9% of 42078 checklistsApr 22-30: 1.0% of 56465 checklistsMay 1-7: 1.1% of 56994 checklistsMay 8-14: 0.8% of 64079 checklistsMay 15-21: 0.5% of 52020 checklistsMay 22-31: 0.2% of 55402 checklistsJun 1-7: 0.1% of 30682 checklistsJun 8-14: 0.1% of 27557 checklistsJun 15-21: 0.1% of 26163 checklistsJun 22-30: 0.2% of 29576 checklistsJul 1-7: 0.2% of 23931 checklistsJul 8-14: 0.2% of 22389 checklistsJul 15-21: 0.3% of 22365 checklistsJul 22-31: 0.3% of 32631 checklistsAug 1-7: 0.6% of 25133 checklistsAug 8-14: 0.6% of 24610 checklistsAug 15-21: 1.0% of 25350 checklistsAug 22-31: 1.6% of 37198 checklistsSep 1-7: 1.9% of 27402 checklistsSep 8-14: 2.9% of 27700 checklistsSep 15-21: 3.3% of 28398 checklistsSep 22-30: 3.2% of 34646 checklistsOct 1-7: 2.9% of 28620 checklistsOct 8-14: 2.7% of 30144 checklistsOct 15-21: 2.2% of 28893 checklistsOct 22-31: 2.0% of 38869 checklistsNov 1-7: 1.6% of 29782 checklistsNov 8-14: 1.6% of 27582 checklistsNov 15-21: 1.4% of 26642 checklistsNov 22-30: 1.3% of 34390 checklistsDec 1-7: 1.2% of 25164 checklistsDec 8-14: 1.3% of 24892 checklistsDec 15-21: 1.3% of 29022 checklistsDec 22-31: 1.5% of 44323 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 Massachusetts 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 Massachusetts

Best counties

Share of checklists at the peak
  1. Nantucket CountyBest late September · 613 checklists that week, 23,895 in all12%
  2. Dukes CountyBest the second week of October · 645 checklists that week, 23,670 in all7.4%
  3. Bristol CountyBest mid September · 980 checklists that week, 65,262 in all5.7%
  4. Essex CountyBest mid September · 3250 checklists that week, 213,973 in all4.7%
  5. Berkshire CountyBest late August · 2311 checklists that week, 92,890 in all4.5%
  6. Franklin CountyBest mid September · 668 checklists that week, 41,382 in all4.5%

Best spots

Share of checklists at the peak
  1. Crystal Lake (Beagle Pond)Worcester County, best late July · 35 checklists that week, 1,431 in all41%
  2. Jackson PointNantucket County, best mid October · 21 checklists that week, 627 in all39%
  3. Horseneck Beach State ReservationBristol County, best late September · 106 checklists that week, 3,088 in all37%
  4. Dartmouth Natural Resources TrustBristol County, best late January · 37 checklists that week, 318 in all35%
  5. Putnam PondWorcester County, best mid February · 20 checklists that week, 1,801 in all35%

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

Best time of day

In Massachusetts, the Merlin is most often listed on checklists started between 6 and 8 am (1.4% of those checklists).

0%0.5%1%1.5%12 am: too few checklists (630) to judge1 am: too few checklists (657) to judge2 am: too few checklists (645) to judge3 am: too few checklists (850) to judge4 am: too few checklists (3787) to judge5 am: too few checklists (29743) to judge6 am: 1.4% of 108601 checklists7 am: 1.4% of 186104 checklists8 am: 1.2% of 185905 checklists9 am: 1.1% of 166049 checklists10 am: 1.0% of 150508 checklists11 am: 0.9% of 131024 checklists12 pm: 0.9% of 116804 checklists1 pm: 1.0% of 112055 checklists2 pm: 1.1% of 110246 checklists3 pm: 1.1% of 104376 checklists4 pm: 1.1% of 83736 checklists5 pm: 1.2% of 63723 checklists6 pm: 0.9% of 41435 checklists7 pm: too few checklists (21041) to judge8 pm: too few checklists (5240) to judge9 pm: too few checklists (1722) to judge10 pm: too few checklists (1094) to judge11 pm: too few checklists (704) 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
January1.2%1.1%1.0%1.1%
February1.1%1.0%0.6%0.8%
March0.7%0.5%0.5%0.7%
April0.8%0.8%0.9%1.0%
May1.1%0.8%0.5%0.2%
June0.1%0.1%0.1%0.2%
July0.2%0.2%0.3%0.3%
August0.6%0.6%1.0%1.6%
September1.9%2.9%3.3%3.2%
October2.9%2.7%2.2%2.0%
November1.6%1.6%1.4%1.3%
December1.2%1.3%1.3%1.5%

Neighboring states

  • Rhode Island: arrives late August, 2 weeks later than Massachusetts
  • New Hampshire: arrives early July, 5 weeks earlier than Massachusetts
  • Connecticut: arrives late August, 2 weeks later than Massachusetts
  • Vermont: arrives late June, 6 weeks earlier than Massachusetts

Common questions

When do Merlins arrive in Massachusetts?
Merlins arrive in Massachusetts in the second week of August, peak in mid September (3.1% of checklists), and most are gone by early March.
When do Merlins leave Massachusetts?
Most Merlins have left Massachusetts by early March, when reports fall below half their usual rate.
When is the best time to see a Merlin in Massachusetts?
The Merlin is reported most often in mid September, on about 3.1% of Massachusetts checklists.
Where in Massachusetts are Merlins seen most often?
By county, Nantucket County, Dukes County, and Bristol County have the highest peak reporting rates for the Merlin (counties with at least 200 checklists).