WhenToBird

2 loon species in New Hampshire

When Do Loons Arrive in New Hampshire?

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

Common Loons and Red-throated Loons are the loons you are most likely to see in New Hampshire. Common Loons are in New Hampshire all year, but most are here in winter: numbers build from mid October, peak in the second week of November (10% of checklists), and fall back by mid January. In the quietest week (mid March) they are still on about 3.6% of checklists.

When to look

Numbers buildOct 15-21mid October
PeakNov 8-14the second week of November
Fall back byJan 15-21mid January
FewestMar 15-21mid March

Best: the second week of November. Here all year; numbers build from mid October and fall back by mid January. Peak: on about 10% of New Hampshire checklists.

  1. Janpeak season
  2. Febcommon
  3. Marcommon
  4. Aprcommon
  5. Maycommon
  6. Junpeak season
  7. Julpeak season
  8. Augpeak season
  9. Sepcommon
  10. Octpeak season
  11. Novpeak season
  12. Decpeak season

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

Loons in New Hampshire, species by species

SpeciesFirst arrivalsCommon byPeakMost gone byPeak %
Common LoonOct 15-21Oct 15-21Nov 8-14Jan 15-2110%
Red-throated LoonOct 15-21Oct 15-21Nov 8-14Jan 15-213.9%
0%5%10%15%Common LoonRed-throated LoonJanFebMarAprMayJunJulAugSepOctNovDec
  • Common Loon
  • Red-throated 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 New Hampshire 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 New Hampshire

Best counties for Common Loon

Share of checklists at the peak
  1. Belknap CountyBest the second week of August · 226 checklists that week, 13,295 in all32%
  2. Rockingham CountyBest mid December · 1367 checklists that week, 84,864 in all25%
  3. Sullivan CountyBest the second week of July · 288 checklists that week, 13,105 in all25%
  4. Carroll CountyBest mid August · 726 checklists that week, 30,580 in all20%
  5. Coos CountyBest the second week of June · 1296 checklists that week, 27,719 in all15%
  6. Grafton CountyBest early August · 853 checklists that week, 45,699 in all11%

Common questions

When do loons arrive in New Hampshire?
Common Loons are in New Hampshire all year, but most are here in winter: numbers build from mid October, peak in the second week of November (10% of checklists), and fall back by mid January. In the quietest week (mid March) they are still on about 3.6% of checklists.
When do loons leave New Hampshire?
Common Loons never fully leave New Hampshire: numbers fall back below half their usual rate by mid January, but some are still reported in every week, about 3.6% of checklists at the low.
When is the best time to see loons in New Hampshire?
The Common Loon is reported most often in the second week of November, on about 10% of New Hampshire checklists.
Which loons are in New Hampshire?
Common Loon and Red-throated Loon are reported regularly; the Common Loon is the most common.