WhenToBird

Vireo swainsoni · Vireonidae

When Do Western Warbling Vireos Arrive in Idaho?

Western Warbling Vireos reach Idaho in early May, are common by mid May, peak in the second week of June (20% of checklists), and most are gone by the second week of September.

When to look

First arrivalsMay 1-7early May
Common byMay 15-21mid May
PeakJun 8-14the second week of June
Most gone bySep 8-14the second week of September

Best: the second week of June. First arrivals early May; most are gone by the second week of September. Peak: on about 20% of Idaho checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Marnot usually seen
  4. Aprnot usually seen
  5. Maycommon
  6. Junpeak season
  7. Julpeak season
  8. Augcommon
  9. Sepuncommon
  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 9357 checklistsJan 8-14: 0% of 6408 checklistsJan 15-21: 0% of 6358 checklistsJan 22-31: 0% of 8601 checklistsFeb 1-7: 0% of 5611 checklistsFeb 8-14: 0% of 6090 checklistsFeb 15-21: 0% of 7973 checklistsFeb 22-28: 0% of 5866 checklistsMar 1-7: 0% of 6144 checklistsMar 8-14: 0% of 6456 checklistsMar 15-21: 0% of 6786 checklistsMar 22-31: 0% of 9539 checklistsApr 1-7: 0% of 7202 checklistsApr 8-14: 0% of 7608 checklistsApr 15-21: 0.1% of 8069 checklistsApr 22-30: 0.1% of 10973 checklistsMay 1-7: 1.2% of 9481 checklistsMay 8-14: 4.2% of 11318 checklistsMay 15-21: 10% of 9141 checklistsMay 22-31: 15% of 13984 checklistsJun 1-7: 19% of 8897 checklistsJun 8-14: 20% of 8504 checklistsJun 15-21: 21% of 8078 checklistsJun 22-30: 19% of 9665 checklistsJul 1-7: 16% of 7144 checklistsJul 8-14: 13% of 6557 checklistsJul 15-21: 12% of 6430 checklistsJul 22-31: 9.4% of 8696 checklistsAug 1-7: 7.6% of 5896 checklistsAug 8-14: 6.6% of 5643 checklistsAug 15-21: 6.4% of 6151 checklistsAug 22-31: 7.0% of 7863 checklistsSep 1-7: 6.6% of 5769 checklistsSep 8-14: 5.7% of 5646 checklistsSep 15-21: 3.4% of 5460 checklistsSep 22-30: 0.9% of 6363 checklistsOct 1-7: 0.1% of 4980 checklistsOct 8-14: 0% of 5096 checklistsOct 15-21: 0% of 4878 checklistsOct 22-31: 0% of 6426 checklistsNov 1-7: 0% of 4822 checklistsNov 8-14: 0% of 4999 checklistsNov 15-21: 0% of 4601 checklistsNov 22-30: 0% of 6027 checklistsDec 1-7: 0% of 4180 checklistsDec 8-14: 0% of 4775 checklistsDec 15-21: 0% of 6522 checklistsDec 22-31: 0% of 7792 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 Idaho 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 Idaho

Best counties

Share of checklists at the peak
  1. Boise CountyBest mid June · 281 checklists that week, 6,761 in all44%
  2. Teton CountyBest mid June · 117 checklists that week, 6,406 in all42%
  3. Bonner CountyBest early June · 278 checklists that week, 10,972 in all41%
  4. Valley CountyBest the second week of June · 338 checklists that week, 8,991 in all35%
  5. Blaine CountyBest late June · 422 checklists that week, 12,004 in all34%
  6. Boundary CountyBest early June · 219 checklists that week, 6,362 in all33%

Best spots

Share of checklists at the peak
  1. Hulls Gulch Reserve (Highlands)Ada County, best late May · 21 checklists that week, 394 in all79%
  2. Bogus Basin State ParkBoise County, best early July · 29 checklists that week, 339 in all72%
  3. Aldape SummitAda County, best late May · 30 checklists that week, 210 in all68%
  4. Caribou National ForestBannock County, best early June · 21 checklists that week, 369 in all68%
  5. Arboretum & Botanical GardenLatah County, best early September · 63 checklists that week, 2,190 in all60%
  6. Lucky Peak State ParkAda County, best the second week of June · 84 checklists that week, 1,311 in all52%

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

Best time of day

In Idaho, the Western Warbling Vireo is most often listed on checklists started between 6 and 8 am (11% of those checklists).

0%5%10%15%20%12 am: too few checklists (180) to judge1 am: too few checklists (176) to judge2 am: too few checklists (169) to judge3 am: too few checklists (164) to judge4 am: too few checklists (450) to judge5 am: too few checklists (2270) to judge6 am: 15% of 9122 checklists7 am: 9.6% of 22204 checklists8 am: 7.3% of 38672 checklists9 am: 5.6% of 38930 checklists10 am: 4.5% of 37338 checklists11 am: 4.2% of 33508 checklists12 pm: 3.3% of 28544 checklists1 pm: 2.9% of 25774 checklists2 pm: 2.2% of 24296 checklists3 pm: 1.9% of 21784 checklists4 pm: 2.7% of 19051 checklists5 pm: 3.2% of 14150 checklists6 pm: 3.6% of 10014 checklists7 pm: 4.7% of 7495 checklists8 pm: too few checklists (4352) to judge9 pm: too few checklists (1449) to judge10 pm: too few checklists (525) to judge11 pm: too few checklists (208) 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%0.1%0.1%
May1.2%4.2%10%15%
June19%20%21%19%
July16%13%12%9.4%
August7.6%6.6%6.4%7.0%
September6.6%5.7%3.4%0.9%
October0.1%0%0%0%
November0%0%0%0%
December0%0%0%0%

Neighboring states

  • Montana: arrives the second week of May, 1 week later than Idaho
  • Utah: arrives late April, 1 week earlier than Idaho
  • Oregon: arrives mid April, 2 weeks earlier than Idaho
  • Washington: arrives mid April, 2 weeks earlier than Idaho

Common questions

When do Western Warbling Vireos arrive in Idaho?
Western Warbling Vireos reach Idaho in early May, are common by mid May, peak in the second week of June (20% of checklists), and most are gone by the second week of September.
When do Western Warbling Vireos leave Idaho?
Most Western Warbling Vireos have left Idaho by the second week of September, when reports fall below half their usual rate. Stragglers are still reported until late September.
When is the best time to see a Western Warbling Vireo in Idaho?
The Western Warbling Vireo is reported most often in the second week of June, on about 20% of Idaho checklists.
Where in Idaho are Western Warbling Vireos seen most often?
By county, Boise County, Teton County, and Bonner County have the highest peak reporting rates for the Western Warbling Vireo (counties with at least 200 checklists).