WhenToBird

Common Loon · Gavia immer

When Do Loons Arrive in Idaho?

Adult Common Loon
Photo: Hungry-Sarracenia Photo, CC BY 4.0 via iNaturalist

Common Loons are winter birds in Idaho: they arrive in early September, peak in late October (5.8% of checklists), and most are gone by the second week of December. They are the only regular loons in Idaho.

When to look

First arrivalsSep 1-7early September
Common bySep 1-7early September
PeakOct 22-31late October
Most gone byDec 8-14the second week of December

Best: late October. First arrivals early September; most are gone by the second week of December. Peak: on about 5.8% of Idaho checklists.

  1. Janrare
  2. Febrare
  3. Marrare
  4. Aprcommon
  5. Maycommon
  6. Junrare
  7. Julrare
  8. Augrare
  9. Sepuncommon
  10. Octpeak season
  11. Novpeak season
  12. Decuncommon

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

Loons in Idaho, species by species

SpeciesFirst arrivalsCommon byPeakMost gone byPeak %
Common LoonSep 1-7Sep 1-7Oct 22-31Dec 8-145.8%
0%2%4%6%8%Common LoonJanFebMarAprMayJunJulAugSepOctNovDec
  • Common Loon
Share of complete checklists reporting each species, by week (4 per month). Gaps: fewer than 10 checklists that week.

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.

Where in Idaho

Best counties for Common Loon

Share of checklists at the peak
  1. Owyhee CountyBest late October · 186 checklists that week, 7,837 in all40%
  2. Jerome CountyBest mid October · 35 checklists that week, 804 in all40%
  3. Power CountyBest mid April · 55 checklists that week, 2,278 in all37%
  4. Valley CountyBest late October · 179 checklists that week, 8,991 in all36%
  5. Franklin CountyBest the second week of April · 16 checklists that week, 651 in all30%
  6. Minidoka CountyBest mid April · 24 checklists that week, 1,365 in all29%

Common questions

When do loons arrive in Idaho?
Common Loons are winter birds in Idaho: they arrive in early September, peak in late October (5.8% of checklists), and most are gone by the second week of December. They are the only regular loons in Idaho.
When do loons leave Idaho?
Most Common Loons have left Idaho by the second week of December, when reports fall below half their usual rate.
When is the best time to see loons in Idaho?
The Common Loon is reported most often in late October, on about 5.8% of Idaho checklists.