WhenToBird

Lophodytes cucullatus · Anatidae

When Do Hooded Mergansers Arrive in Maine?

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

Hooded Mergansers are winter birds in Maine: the first arrive in late July, they are common by the second week of October, peak in the second week of November (11% of checklists), and most are gone by late April.

When to look

First arrivalsJul 22-31late July
Common byOct 8-14the second week of October
PeakNov 8-14the second week of November
Most gone byApr 22-30late April

Best: the second week of November. First arrivals late July; most are gone by late April. Peak: on about 11% of Maine checklists.

  1. Januncommon
  2. Febuncommon
  3. Marpeak season
  4. Aprpeak season
  5. Mayuncommon
  6. Junrare
  7. Juluncommon
  8. Auguncommon
  9. Sepuncommon
  10. Octcommon
  11. Novpeak season
  12. Deccommon

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

0%5%10%15%Jan 1-7: 4.3% of 15499 checklistsJan 8-14: 4.1% of 11141 checklistsJan 15-21: 3.7% of 10729 checklistsJan 22-31: 3.8% of 15084 checklistsFeb 1-7: 3.5% of 9403 checklistsFeb 8-14: 3.6% of 11268 checklistsFeb 15-21: 3.0% of 14061 checklistsFeb 22-28: 4.0% of 9977 checklistsMar 1-7: 5.2% of 9649 checklistsMar 8-14: 7.4% of 11781 checklistsMar 15-21: 9.7% of 11613 checklistsMar 22-31: 11% of 17798 checklistsApr 1-7: 8.9% of 14638 checklistsApr 8-14: 6.9% of 16511 checklistsApr 15-21: 5.1% of 17164 checklistsApr 22-30: 4.2% of 22602 checklistsMay 1-7: 2.7% of 22556 checklistsMay 8-14: 1.8% of 27842 checklistsMay 15-21: 1.6% of 27748 checklistsMay 22-31: 1.5% of 38715 checklistsJun 1-7: 1.4% of 26916 checklistsJun 8-14: 1.7% of 23737 checklistsJun 15-21: 1.2% of 22733 checklistsJun 22-30: 1.2% of 28248 checklistsJul 1-7: 1.2% of 20290 checklistsJul 8-14: 1.4% of 18534 checklistsJul 15-21: 1.3% of 17319 checklistsJul 22-31: 1.7% of 22815 checklistsAug 1-7: 2.1% of 15004 checklistsAug 8-14: 2.0% of 14603 checklistsAug 15-21: 2.1% of 14972 checklistsAug 22-31: 2.1% of 19813 checklistsSep 1-7: 2.3% of 14567 checklistsSep 8-14: 1.9% of 14520 checklistsSep 15-21: 1.8% of 14339 checklistsSep 22-30: 2.5% of 16879 checklistsOct 1-7: 2.8% of 12959 checklistsOct 8-14: 3.4% of 13168 checklistsOct 15-21: 5.1% of 11184 checklistsOct 22-31: 7.4% of 13717 checklistsNov 1-7: 11% of 9823 checklistsNov 8-14: 11% of 9007 checklistsNov 15-21: 10% of 8528 checklistsNov 22-30: 7.9% of 10228 checklistsDec 1-7: 6.3% of 7505 checklistsDec 8-14: 5.0% of 7982 checklistsDec 15-21: 4.0% of 10455 checklistsDec 22-31: 3.4% of 14285 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 Maine 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 Maine

Best counties

Share of checklists at the peak
  1. Androscoggin CountyBest the second week of November · 313 checklists that week, 16,955 in all42%
  2. Aroostook CountyBest late October · 247 checklists that week, 16,817 in all38%
  3. Penobscot CountyBest the second week of November · 823 checklists that week, 56,895 in all27%
  4. Piscataquis CountyBest early November · 52 checklists that week, 14,837 in all17%
  5. Lincoln CountyBest early January · 922 checklists that week, 59,429 in all14%
  6. Kennebec CountyBest mid March · 874 checklists that week, 48,185 in all14%

Best spots

Share of checklists at the peak
  1. Lake JosephineAroostook County, best late October · 31 checklists that week, 460 in all93%
  2. Jagger PondYork County, best early November · 49 checklists that week, 1,870 in all91%
  3. Round PondAndroscoggin County, best mid November · 37 checklists that week, 483 in all88%
  4. Salt BayLincoln County, best the second week of January · 37 checklists that week, 865 in all86%

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

Best time of day

In Maine, the Hooded Merganser is most often listed on checklists started between 9 and 11 am (4.0% of those checklists).

0%2%4%6%12 am: too few checklists (510) to judge1 am: too few checklists (517) to judge2 am: too few checklists (581) to judge3 am: too few checklists (3242) to judge4 am: too few checklists (7221) to judge5 am: 3.2% of 19895 checklists6 am: 3.8% of 54578 checklists7 am: 3.9% of 92775 checklists8 am: 3.9% of 86962 checklists9 am: 4.0% of 78989 checklists10 am: 3.9% of 70954 checklists11 am: 3.9% of 59331 checklists12 pm: 3.8% of 50943 checklists1 pm: 3.8% of 49775 checklists2 pm: 3.8% of 49001 checklists3 pm: 3.7% of 43252 checklists4 pm: 3.1% of 33413 checklists5 pm: 2.3% of 25547 checklists6 pm: 1.7% of 18309 checklists7 pm: too few checklists (14287) to judge8 pm: too few checklists (5336) to judge9 pm: too few checklists (2253) to judge10 pm: too few checklists (1518) to judge11 pm: too few checklists (720) 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
January4.3%4.1%3.7%3.8%
February3.5%3.6%3.0%4.0%
March5.2%7.4%9.7%11%
April8.9%6.9%5.1%4.2%
May2.7%1.8%1.6%1.5%
June1.4%1.7%1.2%1.2%
July1.2%1.4%1.3%1.7%
August2.1%2.0%2.1%2.1%
September2.3%1.9%1.8%2.5%
October2.8%3.4%5.1%7.4%
November11%11%10%7.9%
December6.3%5.0%4.0%3.4%

Neighboring states

  • New Hampshire: arrives early March, 19 weeks earlier than Maine
  • Massachusetts: arrives mid October, 11 weeks later than Maine
  • Vermont: arrives mid July, 1 week earlier than Maine
  • Rhode Island: arrives mid October, 11 weeks later than Maine

Common questions

When do Hooded Mergansers arrive in Maine?
Hooded Mergansers are winter birds in Maine: the first arrive in late July, they are common by the second week of October, peak in the second week of November (11% of checklists), and most are gone by late April.
When do Hooded Mergansers leave Maine?
Most Hooded Mergansers have left Maine by late April, when reports fall below half their usual rate. Stragglers are still reported until mid May.
When is the best time to see a Hooded Merganser in Maine?
The Hooded Merganser is reported most often in the second week of November, on about 11% of Maine checklists.
Where in Maine are Hooded Mergansers seen most often?
By county, Androscoggin County, Aroostook County, and Penobscot County have the highest peak reporting rates for the Hooded Merganser (counties with at least 200 checklists).