WhenToBird

Buteo swainsoni · Accipitridae

When Do Swainson's Hawks Arrive in Washington?

Adult Swainson's Hawk
Photo: Brooke J., CC BY 4.0 via iNaturalist

Swainson's Hawks arrive in Washington in the second week of April, peak in early May (1.1% of checklists), and most are gone by mid September.

When to look

First arrivalsApr 8-14the second week of April
Common byApr 8-14the second week of April
PeakMay 1-7early May
Most gone bySep 15-21mid September

Best: early May. First arrivals the second week of April; most are gone by mid September. Peak: on about 1.1% of Washington checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Marnot usually seen
  4. Aprpeak season
  5. Maypeak season
  6. Juncommon
  7. Julcommon
  8. Augcommon
  9. Sepcommon
  10. Octrare
  11. Novnot usually seen
  12. Decnot usually seen

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

0%0.5%1%1.5%Jan 1-7: 0% of 41928 checklistsJan 8-14: 0% of 31152 checklistsJan 15-21: 0% of 31753 checklistsJan 22-31: 0% of 42530 checklistsFeb 1-7: 0% of 29739 checklistsFeb 8-14: 0% of 32746 checklistsFeb 15-21: 0.1% of 40328 checklistsFeb 22-28: 0% of 28432 checklistsMar 1-7: 0% of 30758 checklistsMar 8-14: 0% of 29368 checklistsMar 15-21: 0% of 32580 checklistsMar 22-31: 0.1% of 45614 checklistsApr 1-7: 0.1% of 33997 checklistsApr 8-14: 0.5% of 34729 checklistsApr 15-21: 1.0% of 38474 checklistsApr 22-30: 1.1% of 52185 checklistsMay 1-7: 1.1% of 44236 checklistsMay 8-14: 1.2% of 48708 checklistsMay 15-21: 1.0% of 41742 checklistsMay 22-31: 0.9% of 57082 checklistsJun 1-7: 0.8% of 39193 checklistsJun 8-14: 0.7% of 36042 checklistsJun 15-21: 0.7% of 34003 checklistsJun 22-30: 0.6% of 39711 checklistsJul 1-7: 0.6% of 31949 checklistsJul 8-14: 0.6% of 29086 checklistsJul 15-21: 0.6% of 28045 checklistsJul 22-31: 0.5% of 38275 checklistsAug 1-7: 0.6% of 28846 checklistsAug 8-14: 0.6% of 28036 checklistsAug 15-21: 0.5% of 27614 checklistsAug 22-31: 0.7% of 40356 checklistsSep 1-7: 0.7% of 31214 checklistsSep 8-14: 0.6% of 27795 checklistsSep 15-21: 0.3% of 29677 checklistsSep 22-30: 0.2% of 35241 checklistsOct 1-7: 0.1% of 28605 checklistsOct 8-14: 0.1% of 28655 checklistsOct 15-21: 0% of 24643 checklistsOct 22-31: 0% of 34874 checklistsNov 1-7: 0% of 25658 checklistsNov 8-14: 0.1% of 25700 checklistsNov 15-21: 0.1% of 24331 checklistsNov 22-30: 0% of 32784 checklistsDec 1-7: 0% of 24099 checklistsDec 8-14: 0% of 23339 checklistsDec 15-21: 0% of 27666 checklistsDec 22-31: 0% 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. Walla Walla CountyBest late April · 1131 checklists that week, 35,829 in all17%
  2. Adams CountyBest the second week of July · 61 checklists that week, 4,574 in all17%
  3. Whitman CountyBest late April · 800 checklists that week, 18,652 in all13%
  4. Franklin CountyBest mid May · 248 checklists that week, 7,970 in all12%
  5. Garfield CountyBest late August · 23 checklists that week, 1,130 in all9.1%
  6. Benton CountyBest the second week of May · 761 checklists that week, 23,565 in all8.7%

Best spots

Share of checklists at the peak
  1. Whitman Mission National Historic SiteWalla Walla County, best early July · 27 checklists that week, 1,992 in all75%
  2. Horn Rapids County ParkBenton County, best the second week of May · 51 checklists that week, 858 in all51%
  3. Fort Walla Walla ParkWalla Walla County, best the second week of May · 29 checklists that week, 685 in all43%
  4. Blalock LakeWalla Walla County, best late April · 32 checklists that week, 337 in all36%

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

Best time of day

In Washington, the Swainson's Hawk is most often listed on checklists started between 5 and 7 pm (0.6% of those checklists).

0%0.5%1%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: 0.7% of 56744 checklists7 am: 0.5% of 133294 checklists8 am: 0.4% of 184196 checklists9 am: 0.4% of 186303 checklists10 am: 0.3% of 177063 checklists11 am: 0.3% of 154936 checklists12 pm: 0.3% of 138061 checklists1 pm: 0.3% of 127449 checklists2 pm: 0.3% of 121511 checklists3 pm: 0.3% of 107793 checklists4 pm: 0.4% of 82862 checklists5 pm: 0.5% of 57183 checklists6 pm: 0.7% 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
January0%0%0%0%
February0%0%0.1%0%
March0%0%0%0.1%
April0.1%0.5%1.0%1.1%
May1.1%1.2%1.0%0.9%
June0.8%0.7%0.7%0.6%
July0.6%0.6%0.6%0.5%
August0.6%0.6%0.5%0.7%
September0.7%0.6%0.3%0.2%
October0.1%0.1%0%0%
November0%0.1%0.1%0%
December0%0%0%0%

Neighboring states

  • Oregon: arrives the second week of April, in the same week than Washington
  • Idaho: arrives early April, 1 week earlier than Washington
  • Montana: arrives mid April, 1 week later than Washington
  • Nevada: arrives early April, 1 week earlier than Washington

Common questions

When do Swainson's Hawks arrive in Washington?
Swainson's Hawks arrive in Washington in the second week of April, peak in early May (1.1% of checklists), and most are gone by mid September.
When do Swainson's Hawks leave Washington?
Most Swainson's Hawks have left Washington by mid September, when reports fall below half their usual rate.
When is the best time to see a Swainson's Hawk in Washington?
The Swainson's Hawk is reported most often in early May, on about 1.1% of Washington checklists.
Where in Washington are Swainson's Hawks seen most often?
By county, Walla Walla County, Adams County, and Whitman County have the highest peak reporting rates for the Swainson's Hawk (counties with at least 200 checklists).