WhenToBird

2 loon species in Delaware

When Do Loons Arrive in Delaware?

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 Delaware. Common Loons are winter birds in Delaware: the first arrive in the second week of October, they are common by early November, peak in the second week of January (9.8% of checklists), and most are gone by mid April.

When to look

First arrivalsOct 8-14the second week of October
Common byNov 1-7early November
PeakJan 8-14the second week of January
Most gone byApr 15-21mid April

Best: the second week of January. First arrivals the second week of October; most are gone by mid April. Peak: on about 9.8% of Delaware checklists.

  1. Janpeak season
  2. Febpeak season
  3. Marcommon
  4. Aprcommon
  5. Mayuncommon
  6. Junrare
  7. Julrare
  8. Augrare
  9. Seprare
  10. Octuncommon
  11. Novcommon
  12. Decpeak season

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

Loons in Delaware, species by species

SpeciesFirst arrivalsCommon byPeakMost gone byPeak %
Common LoonOct 8-14Nov 1-7Jan 8-14Apr 15-219.8%
Red-throated LoonOct 22-31Nov 8-14Jan 8-14Apr 1-79.3%
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 Delaware 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 Delaware

Best counties for Common Loon

Share of checklists at the peak
  1. Sussex CountyBest late January · 2664 checklists that week, 91,027 in all18%
  2. New Castle CountyBest the second week of April · 1835 checklists that week, 72,140 in all2.1%
  3. Kent CountyBest the second week of November · 730 checklists that week, 36,693 in all1.6%

Common questions

When do loons arrive in Delaware?
Common Loons are winter birds in Delaware: the first arrive in the second week of October, they are common by early November, peak in the second week of January (9.8% of checklists), and most are gone by mid April.
When do loons leave Delaware?
Most Common Loons have left Delaware by mid April, when reports fall below half their usual rate. Stragglers are still reported until mid May.
When is the best time to see loons in Delaware?
The Common Loon is reported most often in the second week of January, on about 9.8% of Delaware checklists.
Which loons are in Delaware?
Common Loon and Red-throated Loon are reported regularly; the Common Loon is the most common.