WhenToBird

Nannopterum auritum · Phalacrocoracidae

When Do Double-crested Cormorants Arrive in New Hampshire?

Adult Double-crested Cormorant
Photo: jubileej, CC0 1.0 via iNaturalist

Double-crested Cormorants reach New Hampshire in late March, are common by the second week of April, peak in late August (18% of checklists), and most are gone by the second week of November.

When to look

First arrivalsMar 22-31late March
Common byApr 8-14the second week of April
PeakAug 22-31late August
Most gone byNov 8-14the second week of November

Best: late August. First arrivals late March; most are gone by the second week of November. Peak: on about 18% of New Hampshire checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Marrare
  4. Aprcommon
  5. Maycommon
  6. Juncommon
  7. Julcommon
  8. Augpeak season
  9. Seppeak season
  10. Octpeak season
  11. Novcommon
  12. Decrare

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

0%5%10%15%20%Jan 1-7: 0.5% of 8253 checklistsJan 8-14: 0.2% of 5998 checklistsJan 15-21: 0.1% of 5734 checklistsJan 22-31: 0.1% of 7776 checklistsFeb 1-7: 0.1% of 5253 checklistsFeb 8-14: 0.1% of 6802 checklistsFeb 15-21: 0% of 8852 checklistsFeb 22-28: 0% of 5792 checklistsMar 1-7: 0.1% of 6187 checklistsMar 8-14: 0% of 6977 checklistsMar 15-21: 0.2% of 7863 checklistsMar 22-31: 1.1% of 11746 checklistsApr 1-7: 3.5% of 9329 checklistsApr 8-14: 5.3% of 10499 checklistsApr 15-21: 8.6% of 10376 checklistsApr 22-30: 10% of 13086 checklistsMay 1-7: 11% of 13198 checklistsMay 8-14: 8.6% of 14980 checklistsMay 15-21: 9.1% of 12487 checklistsMay 22-31: 9.3% of 14294 checklistsJun 1-7: 9.1% of 8974 checklistsJun 8-14: 7.0% of 8395 checklistsJun 15-21: 7.5% of 7670 checklistsJun 22-30: 6.8% of 9188 checklistsJul 1-7: 6.0% of 7707 checklistsJul 8-14: 8.0% of 6554 checklistsJul 15-21: 8.1% of 6636 checklistsJul 22-31: 10% of 9599 checklistsAug 1-7: 13% of 6436 checklistsAug 8-14: 15% of 6477 checklistsAug 15-21: 17% of 6510 checklistsAug 22-31: 19% of 9762 checklistsSep 1-7: 18% of 6700 checklistsSep 8-14: 16% of 6012 checklistsSep 15-21: 16% of 6238 checklistsSep 22-30: 15% of 7619 checklistsOct 1-7: 13% of 6702 checklistsOct 8-14: 13% of 6863 checklistsOct 15-21: 14% of 6284 checklistsOct 22-31: 13% of 8287 checklistsNov 1-7: 11% of 7584 checklistsNov 8-14: 7.6% of 6056 checklistsNov 15-21: 4.2% of 5597 checklistsNov 22-30: 2.8% of 7140 checklistsDec 1-7: 1.9% of 4623 checklistsDec 8-14: 0.9% of 4920 checklistsDec 15-21: 0.5% of 6416 checklistsDec 22-31: 0.8% of 7659 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 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.

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 New Hampshire

Best counties

Share of checklists at the peak
  1. Rockingham CountyBest the second week of September · 1271 checklists that week, 84,864 in all43%
  2. Strafford CountyBest the second week of September · 588 checklists that week, 41,888 in all33%
  3. Belknap CountyBest early September · 176 checklists that week, 13,295 in all15%
  4. Merrimack CountyBest late August · 898 checklists that week, 36,980 in all14%
  5. Coos CountyBest early September · 442 checklists that week, 27,719 in all12%
  6. Carroll CountyBest late August · 1037 checklists that week, 30,580 in all7.8%

Best spots

Share of checklists at the peak
  1. Awcomin Swamp (Ragged Neck Point)Rockingham County, best mid September · 23 checklists that week, 834 in all95%
  2. Odiornes PointRockingham County, best early July · 51 checklists that week, 5,375 in all92%
  3. Town of Exeter Sewerage Lagoons ReservoirRockingham County, best late May · 41 checklists that week, 2,293 in all91%
  4. Gosport HarborRockingham County, best late July · 26 checklists that week, 583 in all90%
  5. Hampton HarborRockingham County, best mid August · 23 checklists that week, 611 in all89%
  6. Hoit Road Marsh Wildlife Management AreaMerrimack County, best the second week of April · 20 checklists that week, 286 in all88%

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

Best time of day

In New Hampshire, the Double-crested Cormorant is most often listed on checklists started between 6 and 8 am (8.5% of those checklists).

0%5%10%12 am: too few checklists (219) to judge1 am: too few checklists (192) to judge2 am: too few checklists (176) to judge3 am: too few checklists (234) to judge4 am: too few checklists (1042) to judge5 am: too few checklists (6352) to judge6 am: 10% of 23140 checklists7 am: 7.6% of 43401 checklists8 am: 8.2% of 48039 checklists9 am: 7.0% of 43328 checklists10 am: 7.7% of 37073 checklists11 am: 7.4% of 32028 checklists12 pm: 6.7% of 27396 checklists1 pm: 7.1% of 25182 checklists2 pm: 6.8% of 24318 checklists3 pm: 6.8% of 21974 checklists4 pm: 7.0% of 17958 checklists5 pm: 7.7% of 14528 checklists6 pm: 6.0% of 9144 checklists7 pm: too few checklists (5341) to judge8 pm: too few checklists (1845) to judge9 pm: too few checklists (578) to judge10 pm: too few checklists (346) to judge11 pm: too few checklists (256) 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
January0.5%0.2%0.1%0.1%
February0.1%0.1%0%0%
March0.1%0%0.2%1.1%
April3.5%5.3%8.6%10%
May11%8.6%9.1%9.3%
June9.1%7.0%7.5%6.8%
July6.0%8.0%8.1%10%
August13%15%17%19%
September18%16%16%15%
October13%13%14%13%
November11%7.6%4.2%2.8%
December1.9%0.9%0.5%0.8%

Neighboring states

  • Massachusetts: arrives mid March, 1 week earlier than New Hampshire
  • Vermont: arrives mid March, 1 week earlier than New Hampshire
  • Rhode Island: arrives the second week of March, 2 weeks earlier than New Hampshire
  • Maine: arrives early April, 1 week later than New Hampshire

Common questions

When do Double-crested Cormorants arrive in New Hampshire?
Double-crested Cormorants reach New Hampshire in late March, are common by the second week of April, peak in late August (18% of checklists), and most are gone by the second week of November.
When do Double-crested Cormorants leave New Hampshire?
Most Double-crested Cormorants have left New Hampshire by the second week of November, when reports fall below half their usual rate. Stragglers are still reported until the second week of December.
When is the best time to see a Double-crested Cormorant in New Hampshire?
The Double-crested Cormorant is reported most often in late August, on about 18% of New Hampshire checklists.
Where in New Hampshire are Double-crested Cormorants seen most often?
By county, Rockingham County, Strafford County, and Belknap County have the highest peak reporting rates for the Double-crested Cormorant (counties with at least 200 checklists).