WhenToBird

Lophodytes cucullatus · Anatidae

When Do Hooded Mergansers Arrive in Massachusetts?

Adult male Hooded Merganser
Photo: Justin Flint, CC BY 4.0 via iNaturalist

Hooded Mergansers are winter birds in Massachusetts: the first arrive in mid October, they are common by early November, peak in early December (15% of checklists), and most are gone by early April.

When to look

First arrivalsOct 15-21mid October
Common byNov 1-7early November
PeakDec 1-7early December
Most gone byApr 1-7early April

Best: early December. First arrivals mid October; most are gone by early April. Peak: on about 15% of Massachusetts checklists.

  1. Janpeak season
  2. Febpeak season
  3. Marpeak season
  4. Aprcommon
  5. Mayrare
  6. Junrare
  7. Julnot usually seen
  8. Augnot usually seen
  9. Sepnot usually seen
  10. Octuncommon
  11. Novpeak season
  12. Decpeak season

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

0%5%10%15%20%Jan 1-7: 15% of 43252 checklistsJan 8-14: 14% of 30096 checklistsJan 15-21: 13% of 28760 checklistsJan 22-31: 11% of 38135 checklistsFeb 1-7: 11% of 26442 checklistsFeb 8-14: 10% of 29034 checklistsFeb 15-21: 9.5% of 37383 checklistsFeb 22-28: 13% of 29977 checklistsMar 1-7: 14% of 29175 checklistsMar 8-14: 14% of 32399 checklistsMar 15-21: 13% of 34444 checklistsMar 22-31: 10% of 49126 checklistsApr 1-7: 6.7% of 36456 checklistsApr 8-14: 5.0% of 40908 checklistsApr 15-21: 3.2% of 42078 checklistsApr 22-30: 2.1% of 56465 checklistsMay 1-7: 1.4% of 56994 checklistsMay 8-14: 1.1% of 64079 checklistsMay 15-21: 1.0% of 52020 checklistsMay 22-31: 1.1% of 55402 checklistsJun 1-7: 1.0% of 30682 checklistsJun 8-14: 0.8% of 27557 checklistsJun 15-21: 0.6% of 26163 checklistsJun 22-30: 0.6% of 29576 checklistsJul 1-7: 0.7% of 23931 checklistsJul 8-14: 0.5% of 22389 checklistsJul 15-21: 0.5% of 22365 checklistsJul 22-31: 0.6% of 32631 checklistsAug 1-7: 0.6% of 25133 checklistsAug 8-14: 0.6% of 24610 checklistsAug 15-21: 0.4% of 25350 checklistsAug 22-31: 0.5% of 37198 checklistsSep 1-7: 0.5% of 27402 checklistsSep 8-14: 0.6% of 27700 checklistsSep 15-21: 0.5% of 28398 checklistsSep 22-30: 0.6% of 34646 checklistsOct 1-7: 0.6% of 28620 checklistsOct 8-14: 0.9% of 30144 checklistsOct 15-21: 1.6% of 28893 checklistsOct 22-31: 4.6% of 38869 checklistsNov 1-7: 11% of 29782 checklistsNov 8-14: 12% of 27582 checklistsNov 15-21: 15% of 26642 checklistsNov 22-30: 15% of 34390 checklistsDec 1-7: 16% of 25164 checklistsDec 8-14: 15% of 24892 checklistsDec 15-21: 14% of 29022 checklistsDec 22-31: 13% 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.

Embed this map on your site

Where in Massachusetts

Best counties

Share of checklists at the peak
  1. Berkshire CountyBest late November · 1716 checklists that week, 92,890 in all28%
  2. Nantucket CountyBest early February · 298 checklists that week, 23,895 in all28%
  3. Franklin CountyBest the second week of March · 1061 checklists that week, 41,382 in all21%
  4. Bristol CountyBest early December · 1121 checklists that week, 65,262 in all20%
  5. Middlesex CountyBest late November · 6763 checklists that week, 307,511 in all20%
  6. Hampden CountyBest early March · 761 checklists that week, 35,410 in all19%

Best spots

Share of checklists at the peak
  1. Cambridge ReservoirMiddlesex County, best early December · 37 checklists that week, 1,055 in all98%
  2. Institute ParkWorcester County, best the second week of January · 28 checklists that week, 805 in all97%
  3. Chandler PondSuffolk County, best mid November · 33 checklists that week, 1,769 in all96%
  4. Jug End Fen Wildlife Management AreaBerkshire County, best mid November · 24 checklists that week, 750 in all94%
  5. Ell Pond ParkMiddlesex County, best late November · 89 checklists that week, 3,739 in all94%
  6. Britland ParkBristol County, best the second week of February · 23 checklists that week, 721 in all94%

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

Best time of day

In Massachusetts, the Hooded Merganser is most often listed on checklists started between 2 and 4 pm (7.9% of those checklists).

0%5%10%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: 3.8% of 108601 checklists7 am: 5.1% of 186104 checklists8 am: 6.1% of 185905 checklists9 am: 6.5% of 166049 checklists10 am: 6.9% of 150508 checklists11 am: 7.0% of 131024 checklists12 pm: 7.3% of 116804 checklists1 pm: 7.5% of 112055 checklists2 pm: 8.1% of 110246 checklists3 pm: 7.6% of 104376 checklists4 pm: 5.6% of 83736 checklists5 pm: 2.8% of 63723 checklists6 pm: 1.8% 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
January15%14%13%11%
February11%10%9.5%13%
March14%14%13%10%
April6.7%5.0%3.2%2.1%
May1.4%1.1%1.0%1.1%
June1.0%0.8%0.6%0.6%
July0.7%0.5%0.5%0.6%
August0.6%0.6%0.4%0.5%
September0.5%0.6%0.5%0.6%
October0.6%0.9%1.6%4.6%
November11%12%15%15%
December16%15%14%13%

Neighboring states

  • Rhode Island: arrives mid October, in the same week than Massachusetts
  • New Hampshire: arrives early March, 18 weeks later than Massachusetts
  • Connecticut: arrives mid October, in the same week than Massachusetts
  • Vermont: arrives mid July, 12 weeks earlier than Massachusetts

Common questions

When do Hooded Mergansers arrive in Massachusetts?
Hooded Mergansers are winter birds in Massachusetts: the first arrive in mid October, they are common by early November, peak in early December (15% of checklists), and most are gone by early April.
When do Hooded Mergansers leave Massachusetts?
Most Hooded Mergansers have left Massachusetts by early April, when reports fall below half their usual rate. Stragglers are still reported until early May.
When is the best time to see a Hooded Merganser in Massachusetts?
The Hooded Merganser is reported most often in early December, on about 15% of Massachusetts checklists.
Where in Massachusetts are Hooded Mergansers seen most often?
By county, Berkshire County, Nantucket County, and Franklin County have the highest peak reporting rates for the Hooded Merganser (counties with at least 200 checklists).