WhenToBird

Aythya affinis · Anatidae

When Do Lesser Scaups Arrive in Oregon?

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

Lesser Scaups are winter birds in Oregon: the first arrive in late September, they are common by mid October, peak in early March (9.2% of checklists), and most are gone by early May.

When to look

First arrivalsSep 22-30late September
Common byOct 15-21mid October
PeakMar 1-7early March
Most gone byMay 1-7early May

Best: early March. First arrivals late September; most are gone by early May. Peak: on about 9.2% of Oregon checklists.

  1. Janpeak season
  2. Febpeak season
  3. Marpeak season
  4. Aprpeak season
  5. Maycommon
  6. Jununcommon
  7. Julrare
  8. Augrare
  9. Seprare
  10. Octcommon
  11. Novcommon
  12. Deccommon

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

0%5%10%Jan 1-7: 7.0% of 34973 checklistsJan 8-14: 7.1% of 26807 checklistsJan 15-21: 7.5% of 26567 checklistsJan 22-31: 7.8% of 36019 checklistsFeb 1-7: 8.0% of 24020 checklistsFeb 8-14: 7.0% of 25765 checklistsFeb 15-21: 7.5% of 31019 checklistsFeb 22-28: 8.7% of 24582 checklistsMar 1-7: 9.3% of 24834 checklistsMar 8-14: 9.5% of 24642 checklistsMar 15-21: 8.7% of 27420 checklistsMar 22-31: 9.0% of 39913 checklistsApr 1-7: 8.8% of 28817 checklistsApr 8-14: 8.3% of 31221 checklistsApr 15-21: 6.2% of 34402 checklistsApr 22-30: 5.2% of 47144 checklistsMay 1-7: 4.1% of 37716 checklistsMay 8-14: 3.0% of 39651 checklistsMay 15-21: 2.3% of 37496 checklistsMay 22-31: 2.0% of 56967 checklistsJun 1-7: 1.7% of 35893 checklistsJun 8-14: 1.0% of 31880 checklistsJun 15-21: 0.7% of 30942 checklistsJun 22-30: 0.7% of 38478 checklistsJul 1-7: 0.6% of 27409 checklistsJul 8-14: 0.6% of 25161 checklistsJul 15-21: 0.5% of 25473 checklistsJul 22-31: 0.6% of 33920 checklistsAug 1-7: 0.6% of 24310 checklistsAug 8-14: 0.6% of 23675 checklistsAug 15-21: 0.6% of 23623 checklistsAug 22-31: 0.6% of 33762 checklistsSep 1-7: 0.7% of 25120 checklistsSep 8-14: 0.7% of 24458 checklistsSep 15-21: 0.8% of 25528 checklistsSep 22-30: 1.1% of 31631 checklistsOct 1-7: 1.8% of 25498 checklistsOct 8-14: 2.7% of 25161 checklistsOct 15-21: 4.1% of 23701 checklistsOct 22-31: 5.4% of 30996 checklistsNov 1-7: 6.2% of 21089 checklistsNov 8-14: 6.3% of 21880 checklistsNov 15-21: 7.1% of 21501 checklistsNov 22-30: 6.2% of 28930 checklistsDec 1-7: 6.5% of 19807 checklistsDec 8-14: 5.9% of 21022 checklistsDec 15-21: 5.3% of 24817 checklistsDec 22-31: 5.9% of 37592 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 Oregon 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 Oregon

Best counties

Share of checklists at the peak
  1. Gilliam CountyBest late February · 29 checklists that week, 2,323 in all39%
  2. Hood River CountyBest mid January · 126 checklists that week, 9,695 in all37%
  3. Klamath CountyBest early April · 470 checklists that week, 26,875 in all35%
  4. Crook CountyBest late March · 256 checklists that week, 9,466 in all32%
  5. Morrow CountyBest mid March · 107 checklists that week, 3,484 in all31%
  6. Jefferson CountyBest early December · 86 checklists that week, 11,014 in all27%

Best spots

Share of checklists at the peak
  1. Alkali Canyon (Arlington)Gilliam County, best mid February · 20 checklists that week, 270 in all97%
  2. Local Government 9Benton County, best early April · 135 checklists that week, 6,965 in all95%
  3. Middle Fork Ash CreekPolk County, best late December · 23 checklists that week, 355 in all93%
  4. Verboort ReservoirWashington County, best late January · 34 checklists that week, 155 in all90%

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

Best time of day

In Oregon, the Lesser Scaup is most often listed on checklists started between 1 and 3 pm (5.5% of those checklists).

0%2%4%6%12 am: too few checklists (1505) to judge1 am: too few checklists (675) to judge2 am: too few checklists (626) to judge3 am: too few checklists (1641) to judge4 am: too few checklists (3696) to judge5 am: too few checklists (14524) to judge6 am: 2.0% of 50677 checklists7 am: 3.6% of 125347 checklists8 am: 4.5% of 163668 checklists9 am: 5.1% of 160351 checklists10 am: 5.1% of 148940 checklists11 am: 5.2% of 124743 checklists12 pm: 5.2% of 112537 checklists1 pm: 5.6% of 98999 checklists2 pm: 5.4% of 94690 checklists3 pm: 5.1% of 87923 checklists4 pm: 4.0% of 75235 checklists5 pm: 2.9% of 54504 checklists6 pm: 1.9% of 40469 checklists7 pm: 0.9% of 33675 checklists8 pm: too few checklists (18715) to judge9 pm: too few checklists (5839) to judge10 pm: too few checklists (2704) to judge11 pm: too few checklists (1549) 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
January7.0%7.1%7.5%7.8%
February8.0%7.0%7.5%8.7%
March9.3%9.5%8.7%9.0%
April8.8%8.3%6.2%5.2%
May4.1%3.0%2.3%2.0%
June1.7%1.0%0.7%0.7%
July0.6%0.6%0.5%0.6%
August0.6%0.6%0.6%0.6%
September0.7%0.7%0.8%1.1%
October1.8%2.7%4.1%5.4%
November6.2%6.3%7.1%6.2%
December6.5%5.9%5.3%5.9%

Neighboring states

  • Washington: arrives early October, 1 week later than Oregon
  • Idaho: arrives late August, 4 weeks earlier than Oregon
  • Nevada: arrives mid August, 5 weeks earlier than Oregon
  • California: arrives mid October, 3 weeks later than Oregon

Common questions

When do Lesser Scaups arrive in Oregon?
Lesser Scaups are winter birds in Oregon: the first arrive in late September, they are common by mid October, peak in early March (9.2% of checklists), and most are gone by early May.
When do Lesser Scaups leave Oregon?
Most Lesser Scaups have left Oregon by early May, 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 Lesser Scaup in Oregon?
The Lesser Scaup is reported most often in early March, on about 9.2% of Oregon checklists.
Where in Oregon are Lesser Scaups seen most often?
By county, Gilliam County, Hood River County, and Klamath County have the highest peak reporting rates for the Lesser Scaup (counties with at least 200 checklists).