WhenToBird

Mergus serrator · Anatidae

When Do Red-breasted Mergansers Arrive in Vermont?

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

Red-breasted Mergansers are winter birds in Vermont: they arrive in mid October, peak in early November (1.7% of checklists), and most are gone by late April.

When to look

First arrivalsOct 15-21mid October
Common byOct 15-21mid October
PeakNov 1-7early November
Most gone byApr 22-30late April

Best: early November. First arrivals mid October; most are gone by late April. Peak: on about 1.7% of Vermont checklists.

  1. Janpeak season
  2. Febpeak season
  3. Marcommon
  4. Aprcommon
  5. Mayuncommon
  6. Junnot usually seen
  7. Julnot usually seen
  8. Augnot usually seen
  9. Seprare
  10. Octpeak season
  11. Novpeak season
  12. Deccommon

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

0%0.5%1%1.5%2%Jan 1-7: 1.5% of 12234 checklistsJan 8-14: 1.2% of 8293 checklistsJan 15-21: 1.7% of 7885 checklistsJan 22-31: 1.4% of 10534 checklistsFeb 1-7: 1.0% of 7212 checklistsFeb 8-14: 1.5% of 8144 checklistsFeb 15-21: 1.2% of 10480 checklistsFeb 22-28: 1.2% of 7932 checklistsMar 1-7: 0.8% of 8192 checklistsMar 8-14: 0.8% of 9383 checklistsMar 15-21: 0.6% of 10620 checklistsMar 22-31: 0.7% of 16257 checklistsApr 1-7: 0.8% of 12568 checklistsApr 8-14: 0.7% of 14677 checklistsApr 15-21: 0.9% of 14106 checklistsApr 22-30: 0.7% of 19617 checklistsMay 1-7: 0.6% of 18143 checklistsMay 8-14: 0.2% of 19626 checklistsMay 15-21: 0.1% of 17779 checklistsMay 22-31: 0.1% of 20310 checklistsJun 1-7: 0% of 11493 checklistsJun 8-14: 0.1% of 10215 checklistsJun 15-21: 0% of 9951 checklistsJun 22-30: 0% of 11050 checklistsJul 1-7: 0.1% of 8690 checklistsJul 8-14: 0% of 7679 checklistsJul 15-21: 0.1% of 7687 checklistsJul 22-31: 0.1% of 10712 checklistsAug 1-7: 0% of 7703 checklistsAug 8-14: 0% of 7743 checklistsAug 15-21: 0% of 8314 checklistsAug 22-31: 0% of 12428 checklistsSep 1-7: 0.1% of 9526 checklistsSep 8-14: 0.1% of 8493 checklistsSep 15-21: 0.1% of 8283 checklistsSep 22-30: 0.1% of 10352 checklistsOct 1-7: 0.2% of 8802 checklistsOct 8-14: 0.2% of 9088 checklistsOct 15-21: 1.0% of 7739 checklistsOct 22-31: 1.7% of 10907 checklistsNov 1-7: 1.7% of 7868 checklistsNov 8-14: 1.8% of 7223 checklistsNov 15-21: 1.4% of 7224 checklistsNov 22-30: 1.2% of 8375 checklistsDec 1-7: 0.8% of 6580 checklistsDec 8-14: 0.9% of 6800 checklistsDec 15-21: 0.5% of 8334 checklistsDec 22-31: 0.9% of 10579 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 Vermont 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 Vermont

Best counties

Share of checklists at the peak
  1. Grand Isle CountyBest late November · 150 checklists that week, 8,507 in all7.4%
  2. Chittenden CountyBest early February · 1523 checklists that week, 109,477 in all5.0%
  3. Essex CountyBest late October · 201 checklists that week, 9,416 in all3.7%
  4. Addison CountyBest the second week of January · 1639 checklists that week, 77,064 in all2.0%
  5. Franklin CountyBest early November · 246 checklists that week, 25,284 in all1.8%
  6. Orange CountyBest early November · 192 checklists that week, 16,964 in all1.4%

Best spots

Share of checklists at the peak
  1. Town Farm BayChittenden County, best early November · 35 checklists that week, 361 in all60%
  2. Holmes CreekChittenden County, best late April · 37 checklists that week, 2,478 in all48%
  3. Meach CoveChittenden County, best late April · 25 checklists that week, 1,534 in all39%
  4. Shelburne FarmsChittenden County, best late February · 44 checklists that week, 1,288 in all32%
  5. The GutGrand Isle County, best late November · 25 checklists that week, 185 in all24%

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

Best time of day

In Vermont, the Red-breasted Merganser is most often listed on checklists started between 2 and 4 pm (0.9% of those checklists).

0%0.5%1%12 am: too few checklists (384) to judge1 am: too few checklists (418) to judge2 am: too few checklists (568) to judge3 am: too few checklists (1183) to judge4 am: too few checklists (3460) to judge5 am: 0.1% of 10340 checklists6 am: 0.4% of 30951 checklists7 am: 0.4% of 64150 checklists8 am: 0.4% of 70252 checklists9 am: 0.6% of 55280 checklists10 am: 0.8% of 47111 checklists11 am: 0.8% of 37615 checklists12 pm: 0.9% of 32195 checklists1 pm: 0.8% of 30185 checklists2 pm: 0.9% of 29679 checklists3 pm: 1.0% of 26483 checklists4 pm: 0.6% of 20110 checklists5 pm: 0.3% of 15993 checklists6 pm: 0.2% of 12110 checklists7 pm: too few checklists (8203) to judge8 pm: too few checklists (4425) to judge9 pm: too few checklists (1829) to judge10 pm: too few checklists (597) to judge11 pm: too few checklists (309) 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
January1.5%1.2%1.7%1.4%
February1.0%1.5%1.2%1.2%
March0.8%0.8%0.6%0.7%
April0.8%0.7%0.9%0.7%
May0.6%0.2%0.1%0.1%
June0%0.1%0%0%
July0.1%0%0.1%0.1%
August0%0%0%0%
September0.1%0.1%0.1%0.1%
October0.2%0.2%1.0%1.7%
November1.7%1.8%1.4%1.2%
December0.8%0.9%0.5%0.9%

Neighboring states

  • New Hampshire: arrives mid October, in the same week than Vermont
  • Massachusetts: arrives the second week of October, 1 week earlier than Vermont
  • Connecticut: arrives late October, 1 week later than Vermont
  • Rhode Island: arrives mid October, in the same week than Vermont

Common questions

When do Red-breasted Mergansers arrive in Vermont?
Red-breasted Mergansers are winter birds in Vermont: they arrive in mid October, peak in early November (1.7% of checklists), and most are gone by late April.
When do Red-breasted Mergansers leave Vermont?
Most Red-breasted Mergansers have left Vermont by late April, when reports fall below half their usual rate.
When is the best time to see a Red-breasted Merganser in Vermont?
The Red-breasted Merganser is reported most often in early November, on about 1.7% of Vermont checklists.
Where in Vermont are Red-breasted Mergansers seen most often?
By county, Grand Isle County, Chittenden County, and Essex County have the highest peak reporting rates for the Red-breasted Merganser (counties with at least 200 checklists).