WhenToBird

Nannopterum auritum · Phalacrocoracidae

When Do Double-crested Cormorants Arrive in Minnesota?

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

Double-crested Cormorants reach Minnesota in mid March, are common by the second week of April, peak in late August (15% of checklists), and most are gone by mid October.

When to look

First arrivalsMar 15-21mid March
Common byApr 8-14the second week of April
PeakAug 22-31late August
Most gone byOct 15-21mid October

Best: late August. First arrivals mid March; most are gone by mid October. Peak: on about 15% of Minnesota checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Maruncommon
  4. Aprpeak season
  5. Maypeak season
  6. Juncommon
  7. Julpeak season
  8. Augpeak season
  9. Seppeak season
  10. Octpeak season
  11. Novuncommon
  12. Decnot usually seen

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

0%5%10%15%20%Jan 1-7: 0.1% of 20628 checklistsJan 8-14: 0.1% of 14594 checklistsJan 15-21: 0.1% of 14238 checklistsJan 22-31: 0.2% of 20725 checklistsFeb 1-7: 0.1% of 14484 checklistsFeb 8-14: 0% of 15988 checklistsFeb 15-21: 0.1% of 20718 checklistsFeb 22-28: 0.1% of 15754 checklistsMar 1-7: 0.1% of 16125 checklistsMar 8-14: 0.3% of 19035 checklistsMar 15-21: 0.7% of 19586 checklistsMar 22-31: 1.9% of 30192 checklistsApr 1-7: 4.1% of 24262 checklistsApr 8-14: 8.3% of 30223 checklistsApr 15-21: 11% of 29085 checklistsApr 22-30: 12% of 43574 checklistsMay 1-7: 12% of 39300 checklistsMay 8-14: 10% of 45927 checklistsMay 15-21: 9.8% of 36632 checklistsMay 22-31: 9.9% of 43809 checklistsJun 1-7: 8.7% of 23418 checklistsJun 8-14: 9.0% of 20450 checklistsJun 15-21: 8.2% of 19470 checklistsJun 22-30: 9.0% of 23418 checklistsJul 1-7: 8.7% of 19104 checklistsJul 8-14: 9.3% of 16927 checklistsJul 15-21: 11% of 15635 checklistsJul 22-31: 12% of 22073 checklistsAug 1-7: 13% of 16255 checklistsAug 8-14: 14% of 16840 checklistsAug 15-21: 14% of 17475 checklistsAug 22-31: 15% of 26545 checklistsSep 1-7: 15% of 20750 checklistsSep 8-14: 14% of 18494 checklistsSep 15-21: 13% of 18215 checklistsSep 22-30: 12% of 24463 checklistsOct 1-7: 11% of 18252 checklistsOct 8-14: 9.5% of 19527 checklistsOct 15-21: 7.4% of 17098 checklistsOct 22-31: 3.7% of 24570 checklistsNov 1-7: 2.4% of 16744 checklistsNov 8-14: 1.7% of 13483 checklistsNov 15-21: 1.3% of 12525 checklistsNov 22-30: 0.5% of 17023 checklistsDec 1-7: 0.3% of 11645 checklistsDec 8-14: 0.2% of 11567 checklistsDec 15-21: 0.1% of 13343 checklistsDec 22-31: 0.2% of 19759 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 Minnesota 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 Minnesota

Best counties

Share of checklists at the peak
  1. Grant CountyBest mid June · 71 checklists that week, 2,168 in all62%
  2. Le Sueur CountyBest mid August · 99 checklists that week, 5,034 in all57%
  3. Big Stone CountyBest mid September · 36 checklists that week, 2,678 in all50%
  4. Lac qui Parle CountyBest late June · 58 checklists that week, 3,681 in all50%
  5. Freeborn CountyBest late August · 96 checklists that week, 2,409 in all49%
  6. Lincoln CountyBest mid April · 74 checklists that week, 1,063 in all42%

Best spots

Share of checklists at the peak
  1. Richfield LakeHennepin County, best late August · 74 checklists that week, 1,808 in all98%
  2. Adams- Grotto ParkOtter Tail County, best mid May · 33 checklists that week, 267 in all97%
  3. Agate Bay (southeast)Lake County, best the second week of August · 30 checklists that week, 815 in all93%
  4. Pool 1Hennepin County, best late August · 20 checklists that week, 557 in all92%

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

Best time of day

In Minnesota, the Double-crested Cormorant is most often listed on checklists started between 6 and 8 am (9.8% of those checklists).

0%5%10%15%12 am: too few checklists (349) to judge1 am: too few checklists (331) to judge2 am: too few checklists (286) to judge3 am: too few checklists (364) to judge4 am: too few checklists (863) to judge5 am: too few checklists (7598) to judge6 am: 11% of 35775 checklists7 am: 9.3% of 90565 checklists8 am: 8.1% of 110612 checklists9 am: 7.7% of 106128 checklists10 am: 7.1% of 96131 checklists11 am: 6.4% of 83750 checklists12 pm: 6.0% of 76254 checklists1 pm: 6.1% of 73480 checklists2 pm: 6.3% of 73703 checklists3 pm: 6.2% of 75249 checklists4 pm: 6.9% of 68810 checklists5 pm: 8.3% of 51899 checklists6 pm: 7.3% of 38524 checklists7 pm: 5.7% of 25120 checklists8 pm: too few checklists (10568) to judge9 pm: too few checklists (2420) to judge10 pm: too few checklists (748) to judge11 pm: too few checklists (420) 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
January0.1%0.1%0.1%0.2%
February0.1%0%0.1%0.1%
March0.1%0.3%0.7%1.9%
April4.1%8.3%11%12%
May12%10%9.8%9.9%
June8.7%9.0%8.2%9.0%
July8.7%9.3%11%12%
August13%14%14%15%
September15%14%13%12%
October11%9.5%7.4%3.7%
November2.4%1.7%1.3%0.5%
December0.3%0.2%0.1%0.2%

Neighboring states

  • Iowa: arrives the second week of March, 1 week earlier than Minnesota
  • Wisconsin: arrives late March, 1 week later than Minnesota
  • South Dakota: arrives mid March, in the same week than Minnesota
  • North Dakota: arrives early April, 2 weeks later than Minnesota

Common questions

When do Double-crested Cormorants arrive in Minnesota?
Double-crested Cormorants reach Minnesota in mid March, are common by the second week of April, peak in late August (15% of checklists), and most are gone by mid October.
When do Double-crested Cormorants leave Minnesota?
Most Double-crested Cormorants have left Minnesota by mid October, when reports fall below half their usual rate. Stragglers are still reported until mid November.
When is the best time to see a Double-crested Cormorant in Minnesota?
The Double-crested Cormorant is reported most often in late August, on about 15% of Minnesota checklists.
Where in Minnesota are Double-crested Cormorants seen most often?
By county, Grant County, Le Sueur County, and Big Stone County have the highest peak reporting rates for the Double-crested Cormorant (counties with at least 200 checklists).