WhenToBird

Tachycineta bicolor · Hirundinidae

When Do Tree Swallows Arrive in Oregon?

Adult Tree Swallow
Photo: Carter Dorscht, CC0 1.0 via iNaturalist

Tree Swallows reach Oregon in mid February, are common by the second week of March, peak in the second week of May (27% of checklists), and most are gone by late July.

When to look

First arrivalsFeb 15-21mid February
Common byMar 8-14the second week of March
PeakMay 8-14the second week of May
Most gone byJul 22-31late July

Best: the second week of May. First arrivals mid February; most are gone by late July. Peak: on about 27% of Oregon checklists.

  1. Jannot usually seen
  2. Febuncommon
  3. Marcommon
  4. Aprpeak season
  5. Maypeak season
  6. Junpeak season
  7. Julcommon
  8. Auguncommon
  9. Seprare
  10. Octnot usually seen
  11. Novnot usually seen
  12. Decnot usually seen

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

0%10%20%30%Jan 1-7: 0.2% of 34973 checklistsJan 8-14: 0.1% of 26807 checklistsJan 15-21: 0.2% of 26567 checklistsJan 22-31: 0.6% of 36019 checklistsFeb 1-7: 0.6% of 24020 checklistsFeb 8-14: 1.3% of 25765 checklistsFeb 15-21: 2.1% of 31019 checklistsFeb 22-28: 5.7% of 24582 checklistsMar 1-7: 8.8% of 24834 checklistsMar 8-14: 11% of 24642 checklistsMar 15-21: 14% of 27420 checklistsMar 22-31: 18% of 39913 checklistsApr 1-7: 21% of 28817 checklistsApr 8-14: 24% of 31221 checklistsApr 15-21: 24% of 34402 checklistsApr 22-30: 26% of 47144 checklistsMay 1-7: 28% of 37716 checklistsMay 8-14: 27% of 39651 checklistsMay 15-21: 27% of 37496 checklistsMay 22-31: 25% of 56967 checklistsJun 1-7: 22% of 35893 checklistsJun 8-14: 22% of 31880 checklistsJun 15-21: 22% of 30942 checklistsJun 22-30: 19% of 38478 checklistsJul 1-7: 19% of 27409 checklistsJul 8-14: 16% of 25161 checklistsJul 15-21: 14% of 25473 checklistsJul 22-31: 12% of 33920 checklistsAug 1-7: 9.5% of 24310 checklistsAug 8-14: 7.2% of 23675 checklistsAug 15-21: 5.4% of 23623 checklistsAug 22-31: 3.5% of 33762 checklistsSep 1-7: 2.0% of 25120 checklistsSep 8-14: 1.2% of 24458 checklistsSep 15-21: 1.0% of 25528 checklistsSep 22-30: 0.5% of 31631 checklistsOct 1-7: 0.4% of 25498 checklistsOct 8-14: 0.2% of 25161 checklistsOct 15-21: 0.1% of 23701 checklistsOct 22-31: 0.1% of 30996 checklistsNov 1-7: 0.1% of 21089 checklistsNov 8-14: 0.1% of 21880 checklistsNov 15-21: 0.1% of 21501 checklistsNov 22-30: 0.1% of 28930 checklistsDec 1-7: 0.1% of 19807 checklistsDec 8-14: 0.1% of 21022 checklistsDec 15-21: 0.1% of 24817 checklistsDec 22-31: 0.1% 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. Klamath CountyBest mid May · 752 checklists that week, 26,875 in all46%
  2. Jackson CountyBest early May · 1870 checklists that week, 60,428 in all44%
  3. Crook CountyBest the second week of May · 254 checklists that week, 9,466 in all42%
  4. Columbia CountyBest early May · 582 checklists that week, 27,750 in all39%
  5. Union CountyBest mid May · 1252 checklists that week, 33,301 in all39%
  6. Polk CountyBest mid May · 784 checklists that week, 29,096 in all39%

Best spots

Share of checklists at the peak
  1. Rogue RiverJosephine County, best late April · 26 checklists that week, 408 in all98%
  2. Fernhill WetlandsWashington County, best the second week of May · 158 checklists that week, 6,516 in all98%
  3. Wagonwheel Hole (Oak Island)Columbia County, best late May · 32 checklists that week, 368 in all97%
  4. Bybee LakeMultnomah County, best early June · 38 checklists that week, 1,688 in all97%
  5. Summer Lake Wildlife AreaLake County, best late May · 22 checklists that week, 168 in all95%
  6. Fern Ridge Wildlife Area (Coyote Creek)Lane County, best the second week of July · 42 checklists that week, 981 in all95%

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

Best time of day

In Oregon, the Tree Swallow is most often listed on checklists started between 6 and 8 am (15% of those checklists).

0%5%10%15%20%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: 17% of 50677 checklists7 am: 14% of 125347 checklists8 am: 13% of 163668 checklists9 am: 13% of 160351 checklists10 am: 11% of 148940 checklists11 am: 10% of 124743 checklists12 pm: 9.0% of 112537 checklists1 pm: 8.3% of 98999 checklists2 pm: 8.0% of 94690 checklists3 pm: 8.1% of 87923 checklists4 pm: 8.8% of 75235 checklists5 pm: 10% of 54504 checklists6 pm: 12% of 40469 checklists7 pm: 9.6% 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
January0.2%0.1%0.2%0.6%
February0.6%1.3%2.1%5.7%
March8.8%11%14%18%
April21%24%24%26%
May28%27%27%25%
June22%22%22%19%
July19%16%14%12%
August9.5%7.2%5.4%3.5%
September2.0%1.2%1.0%0.5%
October0.4%0.2%0.1%0.1%
November0.1%0.1%0.1%0.1%
December0.1%0.1%0.1%0.1%

Neighboring states

  • Washington: arrives late February, 1 week later than Oregon
  • Idaho: arrives mid March, 4 weeks later than Oregon
  • Nevada: arrives mid January, 4 weeks earlier than Oregon
  • California: arrives mid January, 4 weeks earlier than Oregon

Common questions

When do Tree Swallows arrive in Oregon?
Tree Swallows reach Oregon in mid February, are common by the second week of March, peak in the second week of May (27% of checklists), and most are gone by late July.
When do Tree Swallows leave Oregon?
Most Tree Swallows have left Oregon by late July, when reports fall below half their usual rate. Stragglers are still reported until early September.
When is the best time to see a Tree Swallow in Oregon?
The Tree Swallow is reported most often in the second week of May, on about 27% of Oregon checklists.
Where in Oregon are Tree Swallows seen most often?
By county, Klamath County, Jackson County, and Crook County have the highest peak reporting rates for the Tree Swallow (counties with at least 200 checklists).