WhenToBird

Aythya affinis · Anatidae

When Do Lesser Scaups Arrive in Washington?

Adult male Lesser Scaup
Photo: Paul Lewis, CC BY 4.0 via iNaturalist

Lesser Scaups are winter birds in Washington: the first arrive in early October, they are common by mid October, peak in mid March (6.8% of checklists), and most are gone by early May.

When to look

First arrivalsOct 1-7early October
Common byOct 15-21mid October
PeakMar 15-21mid March
Most gone byMay 1-7early May

Best: mid March. First arrivals early October; most are gone by early May. Peak: on about 6.8% of Washington checklists.

  1. Janpeak season
  2. Febpeak season
  3. Marpeak season
  4. Aprpeak season
  5. Maycommon
  6. Junrare
  7. Julrare
  8. Augrare
  9. Seprare
  10. Octcommon
  11. Novpeak season
  12. Decpeak season

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

0%2%4%6%8%Jan 1-7: 6.6% of 41928 checklistsJan 8-14: 6.6% of 31152 checklistsJan 15-21: 6.3% of 31753 checklistsJan 22-31: 6.6% of 42530 checklistsFeb 1-7: 6.4% of 29739 checklistsFeb 8-14: 5.4% of 32746 checklistsFeb 15-21: 5.5% of 40328 checklistsFeb 22-28: 6.5% of 28432 checklistsMar 1-7: 6.5% of 30758 checklistsMar 8-14: 6.9% of 29368 checklistsMar 15-21: 6.8% of 32580 checklistsMar 22-31: 6.7% of 45614 checklistsApr 1-7: 6.2% of 33997 checklistsApr 8-14: 5.0% of 34729 checklistsApr 15-21: 4.5% of 38474 checklistsApr 22-30: 3.6% of 52185 checklistsMay 1-7: 2.8% of 44236 checklistsMay 8-14: 1.8% of 48708 checklistsMay 15-21: 1.4% of 41742 checklistsMay 22-31: 1.0% of 57082 checklistsJun 1-7: 0.7% of 39193 checklistsJun 8-14: 0.8% of 36042 checklistsJun 15-21: 0.6% of 34003 checklistsJun 22-30: 0.5% of 39711 checklistsJul 1-7: 0.4% of 31949 checklistsJul 8-14: 0.3% of 29086 checklistsJul 15-21: 0.3% of 28045 checklistsJul 22-31: 0.3% of 38275 checklistsAug 1-7: 0.3% of 28846 checklistsAug 8-14: 0.2% of 28036 checklistsAug 15-21: 0.3% of 27614 checklistsAug 22-31: 0.3% of 40356 checklistsSep 1-7: 0.3% of 31214 checklistsSep 8-14: 0.5% of 27795 checklistsSep 15-21: 0.6% of 29677 checklistsSep 22-30: 0.9% of 35241 checklistsOct 1-7: 1.4% of 28605 checklistsOct 8-14: 1.9% of 28655 checklistsOct 15-21: 3.1% of 24643 checklistsOct 22-31: 4.1% of 34874 checklistsNov 1-7: 4.6% of 25658 checklistsNov 8-14: 4.9% of 25700 checklistsNov 15-21: 4.8% of 24331 checklistsNov 22-30: 5.4% of 32784 checklistsDec 1-7: 5.0% of 24099 checklistsDec 8-14: 4.8% of 23339 checklistsDec 15-21: 4.5% of 27666 checklistsDec 22-31: 5.1% of 42130 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 Washington 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 Washington

Best counties

Share of checklists at the peak
  1. Garfield CountyBest late December · 13 checklists that week, 1,130 in all48%
  2. Adams CountyBest the second week of April · 140 checklists that week, 4,574 in all36%
  3. Skamania CountyBest early February · 177 checklists that week, 10,140 in all32%
  4. Lincoln CountyBest the second week of April · 171 checklists that week, 6,135 in all28%
  5. Franklin CountyBest late February · 85 checklists that week, 7,970 in all23%
  6. Wahkiakum CountyBest early January · 155 checklists that week, 5,618 in all21%

Best spots

Share of checklists at the peak
  1. Marysville Sewage LagoonSnohomish County, best late March · 28 checklists that week, 1,523 in all99%
  2. Lake Wallula (Walla Walla River)Walla Walla County, best the second week of November · 23 checklists that week, 357 in all93%
  3. Elds Island (historical)Grays Harbor County, best early January · 21 checklists that week, 421 in all91%
  4. Big LakeSkagit County, best late January · 24 checklists that week, 215 in all89%

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

Best time of day

In Washington, the Lesser Scaup is most often listed on checklists started between 1 and 3 pm (4.1% of those checklists).

0%2%4%6%12 am: too few checklists (796) to judge1 am: too few checklists (776) to judge2 am: too few checklists (709) to judge3 am: too few checklists (901) to judge4 am: too few checklists (3221) to judge5 am: too few checklists (16576) to judge6 am: 1.8% of 56744 checklists7 am: 2.6% of 133294 checklists8 am: 3.2% of 184196 checklists9 am: 3.5% of 186303 checklists10 am: 3.7% of 177063 checklists11 am: 4.0% of 154936 checklists12 pm: 4.0% of 138061 checklists1 pm: 4.2% of 127449 checklists2 pm: 4.1% of 121511 checklists3 pm: 3.7% of 107793 checklists4 pm: 2.8% of 82862 checklists5 pm: 2.1% of 57183 checklists6 pm: 1.4% of 39886 checklists7 pm: too few checklists (26969) to judge8 pm: too few checklists (12427) to judge9 pm: too few checklists (3658) to judge10 pm: too few checklists (1500) to judge11 pm: too few checklists (834) 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
January6.6%6.6%6.3%6.6%
February6.4%5.4%5.5%6.5%
March6.5%6.9%6.8%6.7%
April6.2%5.0%4.5%3.6%
May2.8%1.8%1.4%1.0%
June0.7%0.8%0.6%0.5%
July0.4%0.3%0.3%0.3%
August0.3%0.2%0.3%0.3%
September0.3%0.5%0.6%0.9%
October1.4%1.9%3.1%4.1%
November4.6%4.9%4.8%5.4%
December5.0%4.8%4.5%5.1%

Neighboring states

  • Oregon: arrives late September, 1 week earlier than Washington
  • Idaho: arrives late August, 5 weeks earlier than Washington
  • Montana: arrives late February, 19 weeks later than Washington
  • Nevada: arrives mid August, 6 weeks earlier than Washington

Common questions

When do Lesser Scaups arrive in Washington?
Lesser Scaups are winter birds in Washington: the first arrive in early October, they are common by mid October, peak in mid March (6.8% of checklists), and most are gone by early May.
When do Lesser Scaups leave Washington?
Most Lesser Scaups have left Washington by early May, when reports fall below half their usual rate. Stragglers are still reported until late May.
When is the best time to see a Lesser Scaup in Washington?
The Lesser Scaup is reported most often in mid March, on about 6.8% of Washington checklists.
Where in Washington are Lesser Scaups seen most often?
By county, Garfield County, Adams County, and Skamania County have the highest peak reporting rates for the Lesser Scaup (counties with at least 200 checklists).