WhenToBird

Mergus merganser · Anatidae

When Do Common Mergansers Arrive in West Virginia?

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

Common Mergansers are winter birds in West Virginia: the first arrive in mid October, they are common by mid November, peak in early February (11% of checklists), and most are gone by the second week of April.

When to look

First arrivalsOct 15-21mid October
Common byNov 15-21mid November
PeakFeb 1-7early February
Most gone byApr 8-14the second week of April

Best: early February. First arrivals mid October; most are gone by the second week of April. Peak: on about 11% of West 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. Novcommon
  12. Deccommon

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

0%5%10%15%Jan 1-7: 7.5% of 4227 checklistsJan 8-14: 8.5% of 3147 checklistsJan 15-21: 8.9% of 3410 checklistsJan 22-31: 12% of 4248 checklistsFeb 1-7: 9.1% of 3150 checklistsFeb 8-14: 9.8% of 3653 checklistsFeb 15-21: 9.4% of 5140 checklistsFeb 22-28: 9.9% of 3846 checklistsMar 1-7: 7.7% of 3901 checklistsMar 8-14: 8.4% of 3820 checklistsMar 15-21: 7.9% of 3781 checklistsMar 22-31: 6.1% of 5705 checklistsApr 1-7: 5.8% of 4529 checklistsApr 8-14: 4.9% of 4935 checklistsApr 15-21: 3.6% of 5429 checklistsApr 22-30: 2.5% of 8015 checklistsMay 1-7: 2.4% of 7421 checklistsMay 8-14: 2.4% of 6910 checklistsMay 15-21: 2.0% of 5596 checklistsMay 22-31: 1.7% of 6884 checklistsJun 1-7: 1.6% of 4123 checklistsJun 8-14: 1.0% of 3957 checklistsJun 15-21: 1.0% of 3863 checklistsJun 22-30: 0.7% of 4217 checklistsJul 1-7: 0.8% of 3491 checklistsJul 8-14: 0.6% of 3044 checklistsJul 15-21: 1.0% of 3095 checklistsJul 22-31: 0.7% of 4120 checklistsAug 1-7: 1.5% of 3009 checklistsAug 8-14: 0.9% of 3007 checklistsAug 15-21: 1.4% of 2905 checklistsAug 22-31: 1.1% of 4312 checklistsSep 1-7: 0.9% of 3429 checklistsSep 8-14: 1.0% of 3217 checklistsSep 15-21: 1.2% of 3285 checklistsSep 22-30: 1.1% of 4067 checklistsOct 1-7: 0.8% of 3380 checklistsOct 8-14: 0.9% of 3460 checklistsOct 15-21: 0.8% of 3129 checklistsOct 22-31: 1.4% of 3881 checklistsNov 1-7: 2.3% of 3084 checklistsNov 8-14: 3.3% of 2869 checklistsNov 15-21: 3.6% of 2484 checklistsNov 22-30: 5.2% of 3663 checklistsDec 1-7: 6.8% of 2574 checklistsDec 8-14: 7.6% of 2680 checklistsDec 15-21: 7.0% of 3792 checklistsDec 22-31: 6.7% of 4236 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 West 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 West Virginia

Best counties

Share of checklists at the peak
  1. Lewis CountyBest the second week of February · 32 checklists that week, 1,802 in all44%
  2. Taylor CountyBest mid January · 49 checklists that week, 2,541 in all43%
  3. Summers CountyBest the second week of December · 86 checklists that week, 5,370 in all43%
  4. Wetzel CountyBest mid January · 46 checklists that week, 1,196 in all39%
  5. Brooke CountyBest late December · 18 checklists that week, 594 in all37%
  6. Doddridge CountyBest early March · 12 checklists that week, 427 in all27%

Best spots

Share of checklists at the peak
  1. Bluestone State ParkSummers County, best mid January · 33 checklists that week, 619 in all87%
  2. Bellepoint ParkSummers County, best early January · 20 checklists that week, 506 in all80%
  3. Deckers CreekMonongalia County, best early February · 22 checklists that week, 277 in all48%
  4. Hannibal PoolWetzel County, best late January · 22 checklists that week, 259 in all45%

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

Best time of day

In West Virginia, the Common Merganser is most often listed on checklists started between 2 and 4 pm (6.0% of those checklists).

0%2%4%6%8%12 am: too few checklists (65) to judge1 am: too few checklists (47) to judge2 am: too few checklists (46) to judge3 am: too few checklists (49) to judge4 am: too few checklists (140) to judge5 am: too few checklists (952) to judge6 am: 2.0% of 5860 checklists7 am: 2.2% of 18233 checklists8 am: 2.9% of 24468 checklists9 am: 3.9% of 22542 checklists10 am: 4.8% of 19537 checklists11 am: 5.4% of 16362 checklists12 pm: 5.0% of 14819 checklists1 pm: 5.5% of 12772 checklists2 pm: 6.3% of 11765 checklists3 pm: 5.8% of 12579 checklists4 pm: 4.0% of 11463 checklists5 pm: 2.5% of 9409 checklists6 pm: 1.6% of 6557 checklists7 pm: 1.5% of 4256 checklists8 pm: too few checklists (1589) to judge9 pm: too few checklists (377) to judge10 pm: too few checklists (147) to judge11 pm: too few checklists (86) 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
January7.5%8.5%8.9%12%
February9.1%9.8%9.4%9.9%
March7.7%8.4%7.9%6.1%
April5.8%4.9%3.6%2.5%
May2.4%2.4%2.0%1.7%
June1.6%1.0%1.0%0.7%
July0.8%0.6%1.0%0.7%
August1.5%0.9%1.4%1.1%
September0.9%1.0%1.2%1.1%
October0.8%0.9%0.8%1.4%
November2.3%3.3%3.6%5.2%
December6.8%7.6%7.0%6.7%

Neighboring states

  • Virginia: arrives early December, 6 weeks later than West Virginia
  • District of Columbia: arrives mid November, 4 weeks later than West Virginia
  • Maryland: arrives mid November, 4 weeks later than West Virginia
  • Ohio: arrives late October, 1 week later than West Virginia

Common questions

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