WhenToBird

Mergus merganser · Anatidae

When Do Common Mergansers Arrive in Nevada?

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

Common Mergansers are winter birds in Nevada: the first arrive in early September, they are common by early November, peak in mid January (14% of checklists), and most are gone by early May.

When to look

First arrivalsSep 1-7early September
Common byNov 1-7early November
PeakJan 15-21mid January
Most gone byMay 1-7early May

Best: mid January. First arrivals early September; most are gone by early May. Peak: on about 14% of Nevada checklists.

  1. Janpeak season
  2. Febpeak season
  3. Marcommon
  4. Aprcommon
  5. Mayuncommon
  6. Jununcommon
  7. Julrare
  8. Augrare
  9. Sepuncommon
  10. Octuncommon
  11. Novcommon
  12. Decpeak season

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

0%5%10%15%Jan 1-7: 14% of 5121 checklistsJan 8-14: 13% of 3908 checklistsJan 15-21: 14% of 4000 checklistsJan 22-31: 14% of 4991 checklistsFeb 1-7: 12% of 3377 checklistsFeb 8-14: 11% of 3747 checklistsFeb 15-21: 9.9% of 4852 checklistsFeb 22-28: 10% of 3712 checklistsMar 1-7: 10% of 3745 checklistsMar 8-14: 9.9% of 3763 checklistsMar 15-21: 10% of 4188 checklistsMar 22-31: 9.7% of 6027 checklistsApr 1-7: 8.0% of 4679 checklistsApr 8-14: 7.3% of 4609 checklistsApr 15-21: 7.5% of 4709 checklistsApr 22-30: 6.7% of 6984 checklistsMay 1-7: 4.9% of 5702 checklistsMay 8-14: 4.4% of 5928 checklistsMay 15-21: 4.1% of 5353 checklistsMay 22-31: 2.8% of 7352 checklistsJun 1-7: 2.0% of 4360 checklistsJun 8-14: 1.8% of 4183 checklistsJun 15-21: 1.7% of 3751 checklistsJun 22-30: 1.5% of 4126 checklistsJul 1-7: 1.1% of 3231 checklistsJul 8-14: 1.9% of 3024 checklistsJul 15-21: 1.7% of 2967 checklistsJul 22-31: 1.7% of 4212 checklistsAug 1-7: 1.3% of 2828 checklistsAug 8-14: 1.6% of 3036 checklistsAug 15-21: 1.6% of 3076 checklistsAug 22-31: 1.9% of 4345 checklistsSep 1-7: 2.2% of 3369 checklistsSep 8-14: 3.2% of 3728 checklistsSep 15-21: 3.0% of 3535 checklistsSep 22-30: 2.9% of 5028 checklistsOct 1-7: 3.2% of 3976 checklistsOct 8-14: 3.0% of 3781 checklistsOct 15-21: 4.1% of 3577 checklistsOct 22-31: 4.5% of 4986 checklistsNov 1-7: 5.9% of 3592 checklistsNov 8-14: 6.7% of 3685 checklistsNov 15-21: 8.0% of 3399 checklistsNov 22-30: 7.0% of 4544 checklistsDec 1-7: 8.8% of 3162 checklistsDec 8-14: 10% of 3191 checklistsDec 15-21: 8.4% of 3615 checklistsDec 22-31: 10% of 5101 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 Nevada 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 Nevada

Best counties

Share of checklists at the peak
  1. Pershing CountyBest early February · 14 checklists that week, 1,407 in all29%
  2. Washoe CountyBest the second week of January · 1371 checklists that week, 53,497 in all21%
  3. Storey CountyBest late April · 47 checklists that week, 1,593 in all20%
  4. Lyon CountyBest early February · 37 checklists that week, 3,229 in all20%
  5. Lincoln CountyBest early January · 46 checklists that week, 3,842 in all17%
  6. Churchill CountyBest early March · 57 checklists that week, 3,104 in all16%

Best spots

Share of checklists at the peak
  1. Crystal Peak ParkWashoe County, best late March · 64 checklists that week, 904 in all92%
  2. Virginia LakeWashoe County, best early April · 20 checklists that week, 836 in all91%
  3. Paradise ParkWashoe County, best early January · 24 checklists that week, 317 in all90%
  4. Idlewild ParkWashoe County, best the second week of May · 23 checklists that week, 879 in all73%
  5. Sparks Marina ParkWashoe County, best the second week of January · 64 checklists that week, 1,441 in all67%

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

Best time of day

In Nevada, the Common Merganser is most often listed on checklists started between 2 and 4 pm (8.1% of those checklists).

0%5%10%12 am: too few checklists (114) to judge1 am: too few checklists (99) to judge2 am: too few checklists (71) to judge3 am: too few checklists (108) to judge4 am: too few checklists (459) to judge5 am: 2.2% of 4313 checklists6 am: 4.1% of 17070 checklists7 am: 5.6% of 27389 checklists8 am: 6.1% of 24858 checklists9 am: 6.5% of 22012 checklists10 am: 7.3% of 19284 checklists11 am: 7.5% of 15592 checklists12 pm: 7.3% of 12432 checklists1 pm: 7.6% of 11386 checklists2 pm: 8.3% of 11262 checklists3 pm: 7.9% of 10721 checklists4 pm: 6.3% of 9090 checklists5 pm: 5.6% of 6397 checklists6 pm: 4.0% of 5012 checklists7 pm: too few checklists (3026) to judge8 pm: too few checklists (905) to judge9 pm: too few checklists (271) to judge10 pm: too few checklists (164) to judge11 pm: too few checklists (120) 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
January14%13%14%14%
February12%11%9.9%10%
March10%9.9%10%9.7%
April8.0%7.3%7.5%6.7%
May4.9%4.4%4.1%2.8%
June2.0%1.8%1.7%1.5%
July1.1%1.9%1.7%1.7%
August1.3%1.6%1.6%1.9%
September2.2%3.2%3.0%2.9%
October3.2%3.0%4.1%4.5%
November5.9%6.7%8.0%7.0%
December8.8%10%8.4%10%

Neighboring states

  • California: arrives mid October, 6 weeks later than Nevada
  • Utah: arrives mid September, 2 weeks later than Nevada
  • Idaho: arrives mid October, 6 weeks later than Nevada
  • Arizona: arrives late November, 11 weeks later than Nevada

Common questions

When do Common Mergansers arrive in Nevada?
Common Mergansers are winter birds in Nevada: the first arrive in early September, they are common by early November, peak in mid January (14% of checklists), and most are gone by early May.
When do Common Mergansers leave Nevada?
Most Common Mergansers have left Nevada by early May, when reports fall below half their usual rate. Stragglers are still reported until early June.
When is the best time to see a Common Merganser in Nevada?
The Common Merganser is reported most often in mid January, on about 14% of Nevada checklists.
Where in Nevada are Common Mergansers seen most often?
By county, Pershing County, Washoe County, and Storey County have the highest peak reporting rates for the Common Merganser (counties with at least 200 checklists).