WhenToBird

Polioptila caerulea · Polioptilidae

When Do Blue-gray Gnatcatchers Arrive in Idaho?

Adult Blue-gray Gnatcatcher
Photo: Laura Clark, CC BY 4.0 via iNaturalist

Blue-gray Gnatcatchers arrive in Idaho in early May, peak in late May (2.1% of checklists), and most are gone by mid September.

When to look

First arrivalsMay 1-7early May
Common byMay 1-7early May
PeakMay 22-31late May
Most gone bySep 15-21mid September

Best: late May. First arrivals early May; most are gone by mid September. Peak: on about 2.1% of Idaho checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Marnot usually seen
  4. Apruncommon
  5. Maypeak season
  6. Junpeak season
  7. Julcommon
  8. Augpeak season
  9. Seppeak season
  10. Octrare
  11. Novnot usually seen
  12. Decnot usually seen

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

0%1%2%3%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: 0.1% of 7608 checklistsApr 15-21: 0% of 8069 checklistsApr 22-30: 0.1% of 10973 checklistsMay 1-7: 1.5% of 9481 checklistsMay 8-14: 1.9% of 11318 checklistsMay 15-21: 2.3% of 9141 checklistsMay 22-31: 2.1% of 13984 checklistsJun 1-7: 1.9% of 8897 checklistsJun 8-14: 1.9% of 8504 checklistsJun 15-21: 1.8% of 8078 checklistsJun 22-30: 1.5% of 9665 checklistsJul 1-7: 1.4% of 7144 checklistsJul 8-14: 1.3% of 6557 checklistsJul 15-21: 1.0% of 6430 checklistsJul 22-31: 0.8% of 8696 checklistsAug 1-7: 1.4% of 5896 checklistsAug 8-14: 0.9% of 5643 checklistsAug 15-21: 1.6% of 6151 checklistsAug 22-31: 2.0% of 7863 checklistsSep 1-7: 2.1% of 5769 checklistsSep 8-14: 1.7% of 5646 checklistsSep 15-21: 1.0% of 5460 checklistsSep 22-30: 0.5% of 6363 checklistsOct 1-7: 0.1% of 4980 checklistsOct 8-14: 0.1% 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: 0.1% 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. Bingham CountyBest the second week of June · 36 checklists that week, 1,427 in all25%
  2. Bannock CountyBest mid August · 145 checklists that week, 8,210 in all15%
  3. Power CountyBest the second week of June · 38 checklists that week, 2,278 in all15%
  4. Cassia CountyBest mid May · 283 checklists that week, 9,223 in all15%
  5. Oneida CountyBest mid June · 93 checklists that week, 1,750 in all14%
  6. Butte CountyBest early August · 36 checklists that week, 1,276 in all12%

Best spots

Share of checklists at the peak
  1. Kinney CreekBannock County, best mid May · 24 checklists that week, 261 in all71%
  2. Elkhorn Warm SpringMadison County, best late May · 23 checklists that week, 204 in all56%
  3. Lydle GulchAda County, best late August · 57 checklists that week, 1,368 in all54%
  4. Barber PoolAda County, best mid May · 39 checklists that week, 1,099 in all24%

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

Best time of day

In Idaho, the Blue-gray Gnatcatcher is most often listed on checklists started between 6 and 8 am (1.6% of those checklists).

0%0.5%1%1.5%2%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: 1.8% of 9122 checklists7 am: 1.5% of 22204 checklists8 am: 1.1% of 38672 checklists9 am: 0.9% of 38930 checklists10 am: 0.6% of 37338 checklists11 am: 0.6% of 33508 checklists12 pm: 0.5% of 28544 checklists1 pm: 0.4% of 25774 checklists2 pm: 0.3% of 24296 checklists3 pm: 0.4% of 21784 checklists4 pm: 0.4% of 19051 checklists5 pm: 0.6% of 14150 checklists6 pm: 0.7% of 10014 checklists7 pm: 0.8% 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%0.1%0%0.1%
May1.5%1.9%2.3%2.1%
June1.9%1.9%1.8%1.5%
July1.4%1.3%1.0%0.8%
August1.4%0.9%1.6%2.0%
September2.1%1.7%1.0%0.5%
October0.1%0.1%0%0%
November0%0%0.1%0%
December0%0%0%0%

Neighboring states

  • Utah: arrives early April, 4 weeks earlier than Idaho
  • Wyoming: arrives late April, 1 week earlier than Idaho
  • Nevada: arrives late March, 5 weeks earlier than Idaho
  • California: arrives early September, 16 weeks later than Idaho

Common questions

When do Blue-gray Gnatcatchers arrive in Idaho?
Blue-gray Gnatcatchers arrive in Idaho in early May, peak in late May (2.1% of checklists), and most are gone by mid September.
When do Blue-gray Gnatcatchers leave Idaho?
Most Blue-gray Gnatcatchers have left Idaho by mid September, when reports fall below half their usual rate.
When is the best time to see a Blue-gray Gnatcatcher in Idaho?
The Blue-gray Gnatcatcher is reported most often in late May, on about 2.1% of Idaho checklists.
Where in Idaho are Blue-gray Gnatcatchers seen most often?
By county, Bingham County, Bannock County, and Power County have the highest peak reporting rates for the Blue-gray Gnatcatcher (counties with at least 200 checklists).