WhenToBird

Vireo swainsoni · Vireonidae

When Do Western Warbling Vireos Arrive in Wyoming?

Western Warbling Vireos reach Wyoming in mid May, are common by late May, peak in mid June (18% of checklists), and most are gone by early August.

When to look

First arrivalsMay 15-21mid May
Common byMay 22-31late May
PeakJun 15-21mid June
Most gone byAug 1-7early August

Best: mid June. First arrivals mid May; most are gone by early August. Peak: on about 18% of Wyoming checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Marnot usually seen
  4. Aprnot usually seen
  5. Mayuncommon
  6. Junpeak season
  7. Julpeak season
  8. Auguncommon
  9. Sepuncommon
  10. Octnot usually seen
  11. Novnot usually seen
  12. Decnot usually seen

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

0%5%10%15%20%Jan 1-7: 0% of 2543 checklistsJan 8-14: 0% of 2114 checklistsJan 15-21: 0% of 1984 checklistsJan 22-31: 0% of 2605 checklistsFeb 1-7: 0% of 1940 checklistsFeb 8-14: 0% of 1954 checklistsFeb 15-21: 0% of 2575 checklistsFeb 22-28: 0% of 1932 checklistsMar 1-7: 0% of 2486 checklistsMar 8-14: 0% of 2535 checklistsMar 15-21: 0% of 2726 checklistsMar 22-31: 0% of 4349 checklistsApr 1-7: 0% of 3300 checklistsApr 8-14: 0% of 3500 checklistsApr 15-21: 0% of 3701 checklistsApr 22-30: 0.1% of 5887 checklistsMay 1-7: 0.1% of 5341 checklistsMay 8-14: 0.5% of 6910 checklistsMay 15-21: 2.0% of 6884 checklistsMay 22-31: 5.8% of 10652 checklistsJun 1-7: 11% of 6807 checklistsJun 8-14: 16% of 6714 checklistsJun 15-21: 19% of 6708 checklistsJun 22-30: 19% of 8160 checklistsJul 1-7: 16% of 5755 checklistsJul 8-14: 13% of 5379 checklistsJul 15-21: 11% of 5299 checklistsJul 22-31: 7.3% of 6830 checklistsAug 1-7: 5.5% of 4581 checklistsAug 8-14: 4.9% of 4625 checklistsAug 15-21: 4.8% of 4466 checklistsAug 22-31: 4.5% of 6562 checklistsSep 1-7: 3.4% of 4543 checklistsSep 8-14: 2.3% of 4652 checklistsSep 15-21: 0.9% of 4186 checklistsSep 22-30: 0.4% of 5301 checklistsOct 1-7: 0.1% of 3248 checklistsOct 8-14: 0.1% of 3010 checklistsOct 15-21: 0% of 2624 checklistsOct 22-31: 0% of 3170 checklistsNov 1-7: 0% of 2110 checklistsNov 8-14: 0% of 2153 checklistsNov 15-21: 0% of 1971 checklistsNov 22-30: 0% of 2136 checklistsDec 1-7: 0% of 1646 checklistsDec 8-14: 0% of 1609 checklistsDec 15-21: 0% of 1954 checklistsDec 22-31: 0% of 2392 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 Wyoming 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 Wyoming

Best counties

Share of checklists at the peak
  1. Carbon CountyBest the second week of June · 425 checklists that week, 6,429 in all33%
  2. Sublette CountyBest late June · 257 checklists that week, 6,738 in all32%
  3. Lincoln CountyBest early July · 129 checklists that week, 3,169 in all29%
  4. Teton CountyBest late June · 2194 checklists that week, 34,686 in all26%
  5. Fremont CountyBest late June · 804 checklists that week, 27,707 in all23%
  6. Albany CountyBest mid June · 483 checklists that week, 21,857 in all21%

Best spots

Share of checklists at the peak
  1. Woods CanyonTeton County, best late June · 22 checklists that week, 232 in all73%
  2. Louis LakeFremont County, best late June · 28 checklists that week, 329 in all73%
  3. Grand Teton National Park (Jenny Lake)Teton County, best late June · 32 checklists that week, 424 in all61%
  4. Christian Pond (Lunch Tree Hill)Teton County, best mid June · 23 checklists that week, 140 in all52%
  5. String LakeTeton County, best late June · 22 checklists that week, 294 in all52%

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

Best time of day

In Wyoming, the Western Warbling Vireo is most often listed on checklists started between 6 and 8 am (7.4% of those checklists).

0%5%10%12 am: too few checklists (59) to judge1 am: too few checklists (76) to judge2 am: too few checklists (86) to judge3 am: too few checklists (79) to judge4 am: too few checklists (326) to judge5 am: too few checklists (2271) to judge6 am: 9.5% of 8808 checklists7 am: 6.4% of 18458 checklists8 am: 5.7% of 22143 checklists9 am: 5.3% of 21499 checklists10 am: 4.9% of 19425 checklists11 am: 4.3% of 16017 checklists12 pm: 3.7% of 13868 checklists1 pm: 3.2% of 12984 checklists2 pm: 2.9% of 12605 checklists3 pm: 2.7% of 11821 checklists4 pm: 3.2% of 10571 checklists5 pm: 4.1% of 8746 checklists6 pm: 4.4% of 6707 checklists7 pm: 5.2% of 4890 checklists8 pm: too few checklists (2323) to judge9 pm: too few checklists (554) to judge10 pm: too few checklists (134) to judge11 pm: too few checklists (59) 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%0%0%0.1%
May0.1%0.5%2.0%5.8%
June11%16%19%19%
July16%13%11%7.3%
August5.5%4.9%4.8%4.5%
September3.4%2.3%0.9%0.4%
October0.1%0.1%0%0%
November0%0%0%0%
December0%0%0%0%

Neighboring states

  • Colorado: arrives early May, 2 weeks earlier than Wyoming
  • Utah: arrives late April, 3 weeks earlier than Wyoming
  • Montana: arrives the second week of May, 1 week earlier than Wyoming
  • Idaho: arrives early May, 2 weeks earlier than Wyoming

Common questions

When do Western Warbling Vireos arrive in Wyoming?
Western Warbling Vireos reach Wyoming in mid May, are common by late May, peak in mid June (18% of checklists), and most are gone by early August.
When do Western Warbling Vireos leave Wyoming?
Most Western Warbling Vireos have left Wyoming by early August, when reports fall below half their usual rate. Stragglers are still reported until mid September.
When is the best time to see a Western Warbling Vireo in Wyoming?
The Western Warbling Vireo is reported most often in mid June, on about 18% of Wyoming checklists.
Where in Wyoming are Western Warbling Vireos seen most often?
By county, Carbon County, Sublette County, and Lincoln County have the highest peak reporting rates for the Western Warbling Vireo (counties with at least 200 checklists).