WhenToBird

Mergus merganser · Anatidae

When Do Common Mergansers Arrive in Virginia?

Adult female Common Merganser
Photo: Christoph Moning, CC BY 4.0 via iNaturalist

Common Mergansers are winter birds in Virginia: the first arrive in early December, they are common by the second week of December, peak in early February (4.0% of checklists), and most are gone by early April.

When to look

First arrivalsDec 1-7early December
Common byDec 8-14the second week of December
PeakFeb 1-7early February
Most gone byApr 1-7early April

Best: early February. First arrivals early December; most are gone by early April. Peak: on about 4.0% of Virginia checklists.

  1. Janpeak season
  2. Febpeak season
  3. Marpeak season
  4. Aprcommon
  5. Mayuncommon
  6. Junrare
  7. Julrare
  8. Augrare
  9. Seprare
  10. Octrare
  11. Novuncommon
  12. Deccommon

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

0%2%4%6%Jan 1-7: 2.8% of 32817 checklistsJan 8-14: 3.4% of 25111 checklistsJan 15-21: 3.4% of 25510 checklistsJan 22-31: 4.0% of 34492 checklistsFeb 1-7: 4.4% of 24950 checklistsFeb 8-14: 3.6% of 28224 checklistsFeb 15-21: 3.2% of 43578 checklistsFeb 22-28: 4.3% of 26467 checklistsMar 1-7: 3.8% of 25851 checklistsMar 8-14: 3.1% of 25901 checklistsMar 15-21: 2.7% of 26747 checklistsMar 22-31: 2.1% of 40819 checklistsApr 1-7: 1.8% of 31351 checklistsApr 8-14: 1.3% of 33239 checklistsApr 15-21: 1.0% of 37284 checklistsApr 22-30: 0.9% of 54364 checklistsMay 1-7: 0.7% of 47698 checklistsMay 8-14: 0.4% of 46174 checklistsMay 15-21: 0.5% of 36444 checklistsMay 22-31: 0.4% of 43203 checklistsJun 1-7: 0.4% of 28503 checklistsJun 8-14: 0.4% of 25485 checklistsJun 15-21: 0.3% of 23728 checklistsJun 22-30: 0.2% of 28785 checklistsJul 1-7: 0.3% of 22294 checklistsJul 8-14: 0.3% of 20481 checklistsJul 15-21: 0.3% of 18914 checklistsJul 22-31: 0.4% of 26976 checklistsAug 1-7: 0.4% of 19555 checklistsAug 8-14: 0.3% of 18744 checklistsAug 15-21: 0.4% of 18721 checklistsAug 22-31: 0.4% of 28763 checklistsSep 1-7: 0.4% of 23594 checklistsSep 8-14: 0.3% of 22581 checklistsSep 15-21: 0.3% of 23036 checklistsSep 22-30: 0.2% of 29687 checklistsOct 1-7: 0.2% of 24321 checklistsOct 8-14: 0.2% of 23946 checklistsOct 15-21: 0.2% of 22191 checklistsOct 22-31: 0.3% of 30161 checklistsNov 1-7: 0.4% of 21431 checklistsNov 8-14: 0.5% of 22758 checklistsNov 15-21: 0.7% of 19988 checklistsNov 22-30: 0.8% of 27665 checklistsDec 1-7: 1.6% of 19324 checklistsDec 8-14: 1.9% of 20316 checklistsDec 15-21: 2.3% of 25675 checklistsDec 22-31: 2.7% of 38677 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 Virginia 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 Virginia

Best counties

Share of checklists at the peak
  1. Covington CountyBest late December · 10 checklists that week, 217 in all50%
  2. Buena Vista CountyBest early January · 14 checklists that week, 525 in all48%
  3. Giles CountyBest late January · 106 checklists that week, 7,514 in all30%
  4. Russell CountyBest the second week of April · 11 checklists that week, 770 in all30%
  5. Amherst CountyBest late January · 267 checklists that week, 9,558 in all22%
  6. Staunton CountyBest late December · 161 checklists that week, 4,717 in all21%

Best spots

Share of checklists at the peak
  1. Beaverdam Creek ReservoirLoudoun County, best mid February · 36 checklists that week, 1,080 in all92%
  2. Beaverdam Creek Reservoir (Waxpool)Loudoun County, best mid February · 37 checklists that week, 455 in all89%
  3. Upper Occoquan Polish PondFairfax County, best mid January · 24 checklists that week, 798 in all82%
  4. Riverbend ParkFairfax County, best mid January · 55 checklists that week, 2,269 in all82%
  5. Cedar LakeLoudoun County, best early March · 27 checklists that week, 537 in all80%
  6. CWT HoldingClarke County, best mid February · 24 checklists that week, 921 in all76%

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

Best time of day

In Virginia, the Common Merganser is most often listed on checklists started between 2 and 4 pm (1.7% of those checklists).

0%0.5%1%1.5%2%12 am: too few checklists (485) to judge1 am: too few checklists (488) to judge2 am: too few checklists (423) to judge3 am: too few checklists (565) to judge4 am: too few checklists (1410) to judge5 am: too few checklists (10265) to judge6 am: 0.8% of 64788 checklists7 am: 1.4% of 169128 checklists8 am: 1.5% of 180748 checklists9 am: 1.4% of 153462 checklists10 am: 1.5% of 128966 checklists11 am: 1.5% of 104204 checklists12 pm: 1.5% of 91604 checklists1 pm: 1.6% of 85547 checklists2 pm: 1.7% of 82355 checklists3 pm: 1.7% of 82265 checklists4 pm: 1.6% of 76714 checklists5 pm: 1.1% of 56782 checklists6 pm: 0.5% of 40131 checklists7 pm: too few checklists (24290) to judge8 pm: too few checklists (7744) to judge9 pm: too few checklists (2383) to judge10 pm: too few checklists (1122) to judge11 pm: too few checklists (651) 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
January2.8%3.4%3.4%4.0%
February4.4%3.6%3.2%4.3%
March3.8%3.1%2.7%2.1%
April1.8%1.3%1.0%0.9%
May0.7%0.4%0.5%0.4%
June0.4%0.4%0.3%0.2%
July0.3%0.3%0.3%0.4%
August0.4%0.3%0.4%0.4%
September0.4%0.3%0.3%0.2%
October0.2%0.2%0.2%0.3%
November0.4%0.5%0.7%0.8%
December1.6%1.9%2.3%2.7%

Neighboring states

  • District of Columbia: arrives mid November, 2 weeks earlier than Virginia
  • Maryland: arrives mid November, 2 weeks earlier than Virginia
  • West Virginia: arrives mid October, 6 weeks earlier than Virginia
  • Delaware: arrives early December, in the same week than Virginia

Common questions

When do Common Mergansers arrive in Virginia?
Common Mergansers are winter birds in Virginia: the first arrive in early December, they are common by the second week of December, peak in early February (4.0% of checklists), and most are gone by early April.
When do Common Mergansers leave Virginia?
Most Common Mergansers have left Virginia by early April, when reports fall below half their usual rate. Stragglers are still reported until mid April.
When is the best time to see a Common Merganser in Virginia?
The Common Merganser is reported most often in early February, on about 4.0% of Virginia checklists.
Where in Virginia are Common Mergansers seen most often?
By county, Covington County, Buena Vista County, and Giles County have the highest peak reporting rates for the Common Merganser (counties with at least 200 checklists).