WhenToBird

Tachycineta bicolor · Hirundinidae

When Do Tree Swallows Arrive in Alaska?

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

Tree Swallows reach Alaska in late April, are common by early May, peak in late May (23% of checklists), and most are gone by the second week of July.

When to look

First arrivalsApr 22-30late April
Common byMay 1-7early May
PeakMay 22-31late May
Most gone byJul 8-14the second week of July

Best: late May. First arrivals late April; most are gone by the second week of July. Peak: on about 23% of Alaska checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Marnot usually seen
  4. Apruncommon
  5. Maypeak season
  6. Junpeak season
  7. Julcommon
  8. Augrare
  9. Sepnot usually seen
  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% of 3788 checklistsJan 8-14: 0% of 2852 checklistsJan 15-21: 0% of 2810 checklistsJan 22-31: 0% of 3629 checklistsFeb 1-7: 0% of 2519 checklistsFeb 8-14: 0% of 2927 checklistsFeb 15-21: 0% of 3743 checklistsFeb 22-28: 0% of 2846 checklistsMar 1-7: 0% of 2904 checklistsMar 8-14: 0% of 3073 checklistsMar 15-21: 0% of 3359 checklistsMar 22-31: 0% of 5855 checklistsApr 1-7: 0.1% of 4329 checklistsApr 8-14: 0.1% of 4949 checklistsApr 15-21: 1.0% of 7114 checklistsApr 22-30: 2.2% of 10916 checklistsMay 1-7: 8.3% of 11827 checklistsMay 8-14: 18% of 14115 checklistsMay 15-21: 25% of 12152 checklistsMay 22-31: 25% of 19919 checklistsJun 1-7: 20% of 15816 checklistsJun 8-14: 17% of 17194 checklistsJun 15-21: 16% of 15943 checklistsJun 22-30: 16% of 16192 checklistsJul 1-7: 15% of 9815 checklistsJul 8-14: 13% of 8263 checklistsJul 15-21: 6.8% of 7081 checklistsJul 22-31: 3.3% of 9434 checklistsAug 1-7: 1.4% of 6380 checklistsAug 8-14: 0.7% of 6258 checklistsAug 15-21: 0.4% of 6114 checklistsAug 22-31: 0.2% of 8189 checklistsSep 1-7: 0.1% of 5848 checklistsSep 8-14: 0.1% of 4853 checklistsSep 15-21: 0% of 4415 checklistsSep 22-30: 0.1% of 5086 checklistsOct 1-7: 0% of 3576 checklistsOct 8-14: 0% of 4212 checklistsOct 15-21: 0% of 3339 checklistsOct 22-31: 0% of 4169 checklistsNov 1-7: 0% of 2844 checklistsNov 8-14: 0% of 2753 checklistsNov 15-21: 0% of 2291 checklistsNov 22-30: 0% of 3066 checklistsDec 1-7: 0% of 2199 checklistsDec 8-14: 0% of 2472 checklistsDec 15-21: 0% of 3071 checklistsDec 22-31: 0% of 3442 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 Alaska 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 Alaska

Best counties

Share of checklists at the peak
  1. Dillingham Census AreaBest the second week of June · 42 checklists that week, 1,426 in all75%
  2. Bethel Census AreaBest early June · 128 checklists that week, 2,783 in all69%
  3. Bristol Bay BoroughBest mid June · 37 checklists that week, 980 in all57%
  4. Lake and Peninsula BoroughBest late May · 31 checklists that week, 1,172 in all47%
  5. Fairbanks North Star BoroughBest late May · 2038 checklists that week, 23,771 in all39%
  6. Kusilvak Census AreaBest the second week of June · 19 checklists that week, 573 in all36%

Best spots

Share of checklists at the peak
  1. Eskimo CreekBristol Bay Borough, best late June · 26 checklists that week, 103 in all94%
  2. Potter MarshAnchorage Municipality, best the second week of June · 262 checklists that week, 4,058 in all94%
  3. Creamer's FieldFairbanks North Star Borough, best early June · 71 checklists that week, 2,118 in all89%
  4. Smith Lake (Happy Creek)Fairbanks North Star Borough, best late May · 35 checklists that week, 274 in all88%

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

Best time of day

In Alaska, the Tree Swallow is most often listed on checklists started between 7 and 9 pm (13% of those checklists).

0%5%10%15%12 am: too few checklists (549) to judge1 am: too few checklists (365) to judge2 am: too few checklists (291) to judge3 am: too few checklists (624) to judge4 am: too few checklists (1241) to judge5 am: too few checklists (3532) to judge6 am: 13% of 9751 checklists7 am: 13% of 17236 checklists8 am: 11% of 24936 checklists9 am: 8.9% of 30139 checklists10 am: 7.7% of 30866 checklists11 am: 7.0% of 28207 checklists12 pm: 6.9% of 25650 checklists1 pm: 6.6% of 24144 checklists2 pm: 6.4% of 23323 checklists3 pm: 6.7% of 20763 checklists4 pm: 7.5% of 18245 checklists5 pm: 9.2% of 14895 checklists6 pm: 11% of 11707 checklists7 pm: 12% of 9365 checklists8 pm: 13% of 6934 checklists9 pm: too few checklists (4176) to judge10 pm: too few checklists (2050) to judge11 pm: too few checklists (952) 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%0%
March0%0%0%0%
April0.1%0.1%1.0%2.2%
May8.3%18%25%25%
June20%17%16%16%
July15%13%6.8%3.3%
August1.4%0.7%0.4%0.2%
September0.1%0.1%0%0.1%
October0%0%0%0%
November0%0%0%0%
December0%0%0%0%

Neighboring states

  • Washington: arrives late February, 8 weeks earlier than Alaska
  • Oregon: arrives mid February, 9 weeks earlier than Alaska
  • Idaho: arrives mid March, 5 weeks earlier than Alaska
  • Montana: arrives mid March, 5 weeks earlier than Alaska

Common questions

When do Tree Swallows arrive in Alaska?
Tree Swallows reach Alaska in late April, are common by early May, peak in late May (23% of checklists), and most are gone by the second week of July.
When do Tree Swallows leave Alaska?
Most Tree Swallows have left Alaska by the second week of July, when reports fall below half their usual rate. Stragglers are still reported until early August.
When is the best time to see a Tree Swallow in Alaska?
The Tree Swallow is reported most often in late May, on about 23% of Alaska checklists.
Where in Alaska are Tree Swallows seen most often?
By county, Dillingham Census Area, Bethel Census Area, and Bristol Bay Borough have the highest peak reporting rates for the Tree Swallow (counties with at least 200 checklists).