WhenToBird

Astur cooperii · Accipitridae

When Do Cooper's Hawks Arrive in Washington?

Adult male Cooper's Hawk
Photo: Shirley Zundell, CC BY 4.0 via iNaturalist

The Cooper's Hawk is in Washington all year. It turns up on about 6.6% of checklists at its peak (early October) and on 2.7% in its quietest week (the second week of June).

When to look

PresentAll year
Peak weekOct 1-7early October
Quietest weekJun 8-14the second week of June

Best: early October. Here all year. Peak: on about 6.6% of Washington checklists.

  1. Janpeak season
  2. Febcommon
  3. Marcommon
  4. Aprcommon
  5. Maycommon
  6. Juncommon
  7. Julcommon
  8. Augpeak season
  9. Seppeak season
  10. Octpeak season
  11. Novpeak season
  12. Decpeak season

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

0%2%4%6%8%Jan 1-7: 4.9% of 41928 checklistsJan 8-14: 4.9% of 31152 checklistsJan 15-21: 4.9% of 31753 checklistsJan 22-31: 4.4% of 42530 checklistsFeb 1-7: 4.5% of 29739 checklistsFeb 8-14: 4.0% of 32746 checklistsFeb 15-21: 4.0% of 40328 checklistsFeb 22-28: 4.0% of 28432 checklistsMar 1-7: 4.1% of 30758 checklistsMar 8-14: 4.1% of 29368 checklistsMar 15-21: 4.3% of 32580 checklistsMar 22-31: 4.2% of 45614 checklistsApr 1-7: 4.4% of 33997 checklistsApr 8-14: 4.8% of 34729 checklistsApr 15-21: 4.5% of 38474 checklistsApr 22-30: 4.5% of 52185 checklistsMay 1-7: 3.7% of 44236 checklistsMay 8-14: 3.3% of 48708 checklistsMay 15-21: 2.8% of 41742 checklistsMay 22-31: 2.7% of 57082 checklistsJun 1-7: 2.7% of 39193 checklistsJun 8-14: 2.6% of 36042 checklistsJun 15-21: 2.8% of 34003 checklistsJun 22-30: 2.9% of 39711 checklistsJul 1-7: 3.0% of 31949 checklistsJul 8-14: 3.2% of 29086 checklistsJul 15-21: 3.4% of 28045 checklistsJul 22-31: 3.9% of 38275 checklistsAug 1-7: 4.9% of 28846 checklistsAug 8-14: 5.7% of 28036 checklistsAug 15-21: 5.6% of 27614 checklistsAug 22-31: 6.1% of 40356 checklistsSep 1-7: 6.1% of 31214 checklistsSep 8-14: 6.5% of 27795 checklistsSep 15-21: 6.4% of 29677 checklistsSep 22-30: 6.5% of 35241 checklistsOct 1-7: 6.6% of 28605 checklistsOct 8-14: 6.6% of 28655 checklistsOct 15-21: 6.4% of 24643 checklistsOct 22-31: 6.2% of 34874 checklistsNov 1-7: 5.6% of 25658 checklistsNov 8-14: 5.7% of 25700 checklistsNov 15-21: 5.6% of 24331 checklistsNov 22-30: 5.4% of 32784 checklistsDec 1-7: 5.7% of 24099 checklistsDec 8-14: 5.8% of 23339 checklistsDec 15-21: 5.4% of 27666 checklistsDec 22-31: 5.2% 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. Adams CountyBest the second week of September · 158 checklists that week, 4,574 in all15%
  2. Benton CountyBest the second week of September · 302 checklists that week, 23,565 in all14%
  3. Franklin CountyBest late September · 168 checklists that week, 7,970 in all12%
  4. Walla Walla CountyBest the second week of October · 579 checklists that week, 35,829 in all11%
  5. King CountyBest early October · 6904 checklists that week, 390,864 in all10%
  6. Douglas CountyBest the second week of December · 130 checklists that week, 9,418 in all9.9%

Best spots

Share of checklists at the peak
  1. W E Johnson ParkBenton County, best late July · 27 checklists that week, 1,031 in all62%
  2. Parsons GardensKing County, best late June · 20 checklists that week, 599 in all53%
  3. Discovery Park (Lawton)King County, best late July · 44 checklists that week, 1,610 in all53%
  4. Hillcrest ParkSkagit County, best late July · 22 checklists that week, 557 in all48%
  5. Union Bay Natural AreaKing County, best the second week of December · 278 checklists that week, 20,611 in all47%

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

Best time of day

In Washington, the Cooper's Hawk is most often listed on checklists started between 6 and 8 am (6.4% of those checklists).

0%2%4%6%8%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: 6.8% of 56744 checklists7 am: 6.3% of 133294 checklists8 am: 6.0% of 184196 checklists9 am: 5.1% of 186303 checklists10 am: 4.8% of 177063 checklists11 am: 4.4% of 154936 checklists12 pm: 3.9% of 138061 checklists1 pm: 3.9% of 127449 checklists2 pm: 3.9% of 121511 checklists3 pm: 3.7% of 107793 checklists4 pm: 3.2% of 82862 checklists5 pm: 3.1% of 57183 checklists6 pm: 2.6% 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
January4.9%4.9%4.9%4.4%
February4.5%4.0%4.0%4.0%
March4.1%4.1%4.3%4.2%
April4.4%4.8%4.5%4.5%
May3.7%3.3%2.8%2.7%
June2.7%2.6%2.8%2.9%
July3.0%3.2%3.4%3.9%
August4.9%5.7%5.6%6.1%
September6.1%6.5%6.4%6.5%
October6.6%6.6%6.4%6.2%
November5.6%5.7%5.6%5.4%
December5.7%5.8%5.4%5.2%

Neighboring states

  • Oregon: summer visitor, peaks late September
  • Idaho: all year, most in fall, peaks mid September
  • Montana: summer visitor, peaks the second week of September
  • Nevada: all year, most in fall, peaks late September

Common questions

When do Cooper's Hawks arrive in Washington?
The Cooper's Hawk is in Washington all year. It turns up on about 6.6% of checklists at its peak (early October) and on 2.7% in its quietest week (the second week of June).
When do Cooper's Hawks leave Washington?
The Cooper's Hawk does not leave Washington: it is reported all year, from 2.7% of checklists in the second week of June to 6.6% in early October.
When is the best time to see a Cooper's Hawk in Washington?
The Cooper's Hawk is reported most often in early October, on about 6.6% of Washington checklists.
Where in Washington are Cooper's Hawks seen most often?
By county, Adams County, Benton County, and Franklin County have the highest peak reporting rates for the Cooper's Hawk (counties with at least 200 checklists).