WhenToBird

Nannopterum auritum · Phalacrocoracidae

When Do Double-crested Cormorants Arrive in Oregon?

Adult Double-crested Cormorant
Photo: jubileej, CC0 1.0 via iNaturalist

Double-crested Cormorants are in Oregon all year, but most are here in fall: numbers build from early September, peak in the second week of November (17% of checklists), and fall back by early February. In the quietest week (the second week of June) they are still on about 5.5% of checklists.

When to look

Numbers buildSep 1-7early September
PeakNov 8-14the second week of November
Fall back byFeb 1-7early February
FewestJun 8-14the second week of June

Best: the second week of November. Here all year; numbers build from early September and fall back by early February. Peak: on about 17% of Oregon checklists.

  1. Janpeak season
  2. Febcommon
  3. Marcommon
  4. Aprcommon
  5. Maycommon
  6. Jununcommon
  7. Julcommon
  8. Augcommon
  9. Sepcommon
  10. Octpeak season
  11. Novpeak season
  12. Decpeak season

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

0%5%10%15%20%Jan 1-7: 13% of 34973 checklistsJan 8-14: 13% of 26807 checklistsJan 15-21: 12% of 26567 checklistsJan 22-31: 13% of 36019 checklistsFeb 1-7: 12% of 24020 checklistsFeb 8-14: 11% of 25765 checklistsFeb 15-21: 10% of 31019 checklistsFeb 22-28: 11% of 24582 checklistsMar 1-7: 12% of 24834 checklistsMar 8-14: 11% of 24642 checklistsMar 15-21: 11% of 27420 checklistsMar 22-31: 11% of 39913 checklistsApr 1-7: 10% of 28817 checklistsApr 8-14: 9.8% of 31221 checklistsApr 15-21: 8.5% of 34402 checklistsApr 22-30: 7.6% of 47144 checklistsMay 1-7: 6.8% of 37716 checklistsMay 8-14: 6.0% of 39651 checklistsMay 15-21: 6.1% of 37496 checklistsMay 22-31: 5.7% of 56967 checklistsJun 1-7: 5.3% of 35893 checklistsJun 8-14: 5.4% of 31880 checklistsJun 15-21: 5.7% of 30942 checklistsJun 22-30: 5.6% of 38478 checklistsJul 1-7: 6.4% of 27409 checklistsJul 8-14: 7.2% of 25161 checklistsJul 15-21: 8.1% of 25473 checklistsJul 22-31: 9.0% of 33920 checklistsAug 1-7: 9.9% of 24310 checklistsAug 8-14: 11% of 23675 checklistsAug 15-21: 11% of 23623 checklistsAug 22-31: 11% of 33762 checklistsSep 1-7: 11% of 25120 checklistsSep 8-14: 12% of 24458 checklistsSep 15-21: 12% of 25528 checklistsSep 22-30: 11% of 31631 checklistsOct 1-7: 11% of 25498 checklistsOct 8-14: 13% of 25161 checklistsOct 15-21: 13% of 23701 checklistsOct 22-31: 16% of 30996 checklistsNov 1-7: 17% of 21089 checklistsNov 8-14: 17% of 21880 checklistsNov 15-21: 17% of 21501 checklistsNov 22-30: 15% of 28930 checklistsDec 1-7: 13% of 19807 checklistsDec 8-14: 12% of 21022 checklistsDec 15-21: 12% of 24817 checklistsDec 22-31: 12% 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. Sherman CountyBest the second week of November · 238 checklists that week, 4,629 in all53%
  2. Hood River CountyBest the second week of November · 176 checklists that week, 9,695 in all50%
  3. Wasco CountyBest early November · 142 checklists that week, 13,127 in all45%
  4. Tillamook CountyBest early September · 938 checklists that week, 45,809 in all41%
  5. Morrow CountyBest early December · 19 checklists that week, 3,484 in all35%
  6. Lincoln CountyBest early November · 1275 checklists that week, 66,994 in all35%

Best spots

Share of checklists at the peak
  1. Kellogg Creek Water Pollution Control PlantClackamas County, best mid January · 23 checklists that week, 409 in all99%
  2. Ork ReefDouglas County, best late July · 30 checklists that week, 392 in all98%
  3. Willamette ParkMultnomah County, best early January · 24 checklists that week, 661 in all97%
  4. Lone Pine IslandWasco County, best late October · 30 checklists that week, 303 in all96%
  5. Rogue River (Allen Creek)Josephine County, best early January · 25 checklists that week, 363 in all96%

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

Best time of day

In Oregon, the Double-crested Cormorant is most often listed on checklists started between 1 and 3 pm (12% of those checklists).

0%5%10%15%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: 6.8% of 50677 checklists7 am: 9.1% of 125347 checklists8 am: 11% of 163668 checklists9 am: 11% of 160351 checklists10 am: 12% of 148940 checklists11 am: 12% of 124743 checklists12 pm: 11% of 112537 checklists1 pm: 12% of 98999 checklists2 pm: 12% of 94690 checklists3 pm: 11% of 87923 checklists4 pm: 8.9% of 75235 checklists5 pm: 7.4% of 54504 checklists6 pm: 5.7% of 40469 checklists7 pm: 3.2% 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
January13%13%12%13%
February12%11%10%11%
March12%11%11%11%
April10%9.8%8.5%7.6%
May6.8%6.0%6.1%5.7%
June5.3%5.4%5.7%5.6%
July6.4%7.2%8.1%9.0%
August9.9%11%11%11%
September11%12%12%11%
October11%13%13%16%
November17%17%17%15%
December13%12%12%12%

Neighboring states

  • Washington: arrives early September, in the same week than Oregon
  • Idaho: arrives the second week of July, 7 weeks earlier than Oregon
  • Nevada: year-round, peaks late March
  • California: year-round, peaks late November

Common questions

When do Double-crested Cormorants arrive in Oregon?
Double-crested Cormorants are in Oregon all year, but most are here in fall: numbers build from early September, peak in the second week of November (17% of checklists), and fall back by early February. In the quietest week (the second week of June) they are still on about 5.5% of checklists.
When do Double-crested Cormorants leave Oregon?
Double-crested Cormorants never fully leave Oregon: numbers fall back below half their usual rate by early February, but some are still reported in every week, about 5.5% of checklists at the low.
When is the best time to see a Double-crested Cormorant in Oregon?
The Double-crested Cormorant is reported most often in the second week of November, on about 17% of Oregon checklists.
Where in Oregon are Double-crested Cormorants seen most often?
By county, Sherman County, Hood River County, and Wasco County have the highest peak reporting rates for the Double-crested Cormorant (counties with at least 200 checklists).