WhenToBird

Mergus serrator · Anatidae

When Do Red-breasted Mergansers Arrive in Alaska?

Adult male Red-breasted Merganser
Photo: Peter Chen 2.0, CC BY 4.0 via iNaturalist

Red-breasted Mergansers are winter birds in Alaska: the first arrive in mid September, they are common by mid October, peak in early February (13% of checklists), and most are gone by the second week of June.

When to look

First arrivalsSep 15-21mid September
Common byOct 15-21mid October
PeakFeb 1-7early February
Most gone byJun 8-14the second week of June

Best: early February. First arrivals mid September; most are gone by the second week of June. Peak: on about 13% of Alaska checklists.

  1. Janpeak season
  2. Febpeak season
  3. Marpeak season
  4. Aprcommon
  5. Maycommon
  6. Juncommon
  7. Juluncommon
  8. Augrare
  9. Sepuncommon
  10. Octcommon
  11. Novpeak season
  12. Decpeak season

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

0%5%10%15%Jan 1-7: 12% of 3788 checklistsJan 8-14: 12% of 2852 checklistsJan 15-21: 13% of 2810 checklistsJan 22-31: 13% of 3629 checklistsFeb 1-7: 14% of 2519 checklistsFeb 8-14: 13% of 2927 checklistsFeb 15-21: 12% of 3743 checklistsFeb 22-28: 11% of 2846 checklistsMar 1-7: 12% of 2904 checklistsMar 8-14: 13% of 3073 checklistsMar 15-21: 11% of 3359 checklistsMar 22-31: 9.7% of 5855 checklistsApr 1-7: 9.4% of 4329 checklistsApr 8-14: 8.2% of 4949 checklistsApr 15-21: 7.8% of 7114 checklistsApr 22-30: 6.6% of 10916 checklistsMay 1-7: 7.8% of 11827 checklistsMay 8-14: 6.1% of 14115 checklistsMay 15-21: 5.1% of 12152 checklistsMay 22-31: 6.0% of 19919 checklistsJun 1-7: 7.5% of 15816 checklistsJun 8-14: 5.5% of 17194 checklistsJun 15-21: 4.0% of 15943 checklistsJun 22-30: 3.3% of 16192 checklistsJul 1-7: 2.8% of 9815 checklistsJul 8-14: 2.2% of 8263 checklistsJul 15-21: 2.0% of 7081 checklistsJul 22-31: 2.0% of 9434 checklistsAug 1-7: 1.3% of 6380 checklistsAug 8-14: 1.0% of 6258 checklistsAug 15-21: 1.0% of 6114 checklistsAug 22-31: 1.2% of 8189 checklistsSep 1-7: 1.2% of 5848 checklistsSep 8-14: 1.7% of 4853 checklistsSep 15-21: 3.0% of 4415 checklistsSep 22-30: 3.8% of 5086 checklistsOct 1-7: 4.1% of 3576 checklistsOct 8-14: 4.1% of 4212 checklistsOct 15-21: 6.2% of 3339 checklistsOct 22-31: 7.3% of 4169 checklistsNov 1-7: 9.6% of 2844 checklistsNov 8-14: 8.8% of 2753 checklistsNov 15-21: 9.9% of 2291 checklistsNov 22-30: 11% of 3066 checklistsDec 1-7: 11% of 2199 checklistsDec 8-14: 11% of 2472 checklistsDec 15-21: 13% of 3071 checklistsDec 22-31: 13% of 3442 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 Alaska 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 Alaska

Best counties

Share of checklists at the peak
  1. Hoonah-Angoon Census AreaBest early December · 56 checklists that week, 8,159 in all49%
  2. Aleutians East BoroughBest the second week of January · 11 checklists that week, 1,634 in all48%
  3. Aleutians West Census AreaBest early March · 14 checklists that week, 6,087 in all48%
  4. Prince of Wales-Hyder Census AreaBest mid February · 23 checklists that week, 2,822 in all45%
  5. Kodiak Island BoroughBest late April · 413 checklists that week, 11,483 in all45%
  6. Petersburg BoroughBest early March · 107 checklists that week, 6,063 in all45%

Best spots

Share of checklists at the peak
  1. Kalsin PondKodiak Island Borough, best mid May · 41 checklists that week, 798 in all74%
  2. Point LouisaJuneau City and Borough, best late January · 32 checklists that week, 984 in all71%
  3. Lake OrbinKodiak Island Borough, best the second week of May · 31 checklists that week, 432 in all71%
  4. Genivieve LakeKodiak Island Borough, best late March · 21 checklists that week, 516 in all67%

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

Best time of day

In Alaska, the Red-breasted Merganser is most often listed on checklists started between 10 am and 12 pm (6.9% of those checklists).

0%2%4%6%8%12 am: too few checklists (549) to judge1 am: too few checklists (365) to judge2 am: too few checklists (291) to judge3 am: too few checklists (624) to judge4 am: too few checklists (1241) to judge5 am: too few checklists (3532) to judge6 am: 4.4% of 9751 checklists7 am: 5.0% of 17236 checklists8 am: 6.0% of 24936 checklists9 am: 6.7% of 30139 checklists10 am: 7.0% of 30866 checklists11 am: 6.9% of 28207 checklists12 pm: 6.5% of 25650 checklists1 pm: 6.7% of 24144 checklists2 pm: 6.6% of 23323 checklists3 pm: 6.3% of 20763 checklists4 pm: 5.7% of 18245 checklists5 pm: 4.5% of 14895 checklists6 pm: 4.6% of 11707 checklists7 pm: 4.2% of 9365 checklists8 pm: 4.8% of 6934 checklists9 pm: too few checklists (4176) to judge10 pm: too few checklists (2050) to judge11 pm: too few checklists (952) 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
January12%12%13%13%
February14%13%12%11%
March12%13%11%9.7%
April9.4%8.2%7.8%6.6%
May7.8%6.1%5.1%6.0%
June7.5%5.5%4.0%3.3%
July2.8%2.2%2.0%2.0%
August1.3%1.0%1.0%1.2%
September1.2%1.7%3.0%3.8%
October4.1%4.1%6.2%7.3%
November9.6%8.8%9.9%11%
December11%11%13%13%

Neighboring states

  • Washington: arrives the second week of October, 3 weeks later than Alaska
  • Oregon: arrives late October, 5 weeks later than Alaska
  • Idaho: arrives mid October, 4 weeks later than Alaska
  • Montana: arrives late February, 21 weeks later than Alaska

Common questions

When do Red-breasted Mergansers arrive in Alaska?
Red-breasted Mergansers are winter birds in Alaska: the first arrive in mid September, they are common by mid October, peak in early February (13% of checklists), and most are gone by the second week of June.
When do Red-breasted Mergansers leave Alaska?
Most Red-breasted Mergansers have left Alaska by the second week of June, when reports fall below half their usual rate. Stragglers are still reported until mid July.
When is the best time to see a Red-breasted Merganser in Alaska?
The Red-breasted Merganser is reported most often in early February, on about 13% of Alaska checklists.
Where in Alaska are Red-breasted Mergansers seen most often?
By county, Hoonah-Angoon Census Area, Aleutians East Borough, and Aleutians West Census Area have the highest peak reporting rates for the Red-breasted Merganser (counties with at least 200 checklists).