WhenToBird

Hydroprogne caspia · Laridae

When Do Caspian Terns Arrive in Michigan?

Adult Caspian Tern
Photo: Daughter Dad, CC BY 4.0 via iNaturalist

Caspian Terns reach Michigan in the second week of April, are common by mid April, peak in the second week of August (6.2% of checklists), and most are gone by the second week of September.

When to look

First arrivalsApr 8-14the second week of April
Common byApr 15-21mid April
PeakAug 8-14the second week of August
Most gone bySep 8-14the second week of September

Best: the second week of August. First arrivals the second week of April; most are gone by the second week of September. Peak: on about 6.2% of Michigan checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Marnot usually seen
  4. Aprcommon
  5. Maycommon
  6. Juncommon
  7. Julpeak season
  8. Augpeak season
  9. Sepcommon
  10. Octrare
  11. Novnot usually seen
  12. Decnot usually seen

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

0%2%4%6%8%Jan 1-7: 0% of 38160 checklistsJan 8-14: 0% of 24696 checklistsJan 15-21: 0% of 23771 checklistsJan 22-31: 0% of 31347 checklistsFeb 1-7: 0% of 23225 checklistsFeb 8-14: 0% of 27398 checklistsFeb 15-21: 0% of 36606 checklistsFeb 22-28: 0% of 27127 checklistsMar 1-7: 0% of 29700 checklistsMar 8-14: 0% of 31587 checklistsMar 15-21: 0.1% of 32118 checklistsMar 22-31: 0.1% of 47777 checklistsApr 1-7: 0.4% of 38557 checklistsApr 8-14: 1.4% of 42207 checklistsApr 15-21: 3.0% of 42759 checklistsApr 22-30: 3.7% of 64458 checklistsMay 1-7: 3.4% of 60998 checklistsMay 8-14: 3.1% of 72091 checklistsMay 15-21: 5.0% of 59058 checklistsMay 22-31: 3.7% of 64724 checklistsJun 1-7: 2.9% of 35990 checklistsJun 8-14: 2.6% of 32595 checklistsJun 15-21: 2.9% of 30017 checklistsJun 22-30: 3.4% of 33988 checklistsJul 1-7: 4.3% of 28708 checklistsJul 8-14: 4.2% of 25175 checklistsJul 15-21: 4.7% of 24084 checklistsJul 22-31: 5.3% of 33522 checklistsAug 1-7: 6.1% of 25098 checklistsAug 8-14: 6.3% of 24353 checklistsAug 15-21: 6.3% of 25059 checklistsAug 22-31: 5.1% of 37489 checklistsSep 1-7: 3.0% of 28410 checklistsSep 8-14: 2.2% of 27887 checklistsSep 15-21: 2.3% of 26614 checklistsSep 22-30: 1.1% of 32557 checklistsOct 1-7: 0.8% of 25844 checklistsOct 8-14: 0.4% of 27741 checklistsOct 15-21: 0.2% of 24693 checklistsOct 22-31: 0.1% of 32460 checklistsNov 1-7: 0.1% of 23660 checklistsNov 8-14: 0.1% of 21542 checklistsNov 15-21: 0% of 19922 checklistsNov 22-30: 0% of 25069 checklistsDec 1-7: 0% of 18272 checklistsDec 8-14: 0.1% of 18961 checklistsDec 15-21: 0% of 24171 checklistsDec 22-31: 0% of 30908 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 Michigan 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 Michigan

Best counties

Share of checklists at the peak
  1. Monroe CountyBest mid August · 609 checklists that week, 22,078 in all51%
  2. Bay CountyBest mid June · 402 checklists that week, 16,522 in all49%
  3. Arenac CountyBest early September · 88 checklists that week, 4,464 in all28%
  4. Alpena CountyBest late April · 108 checklists that week, 3,793 in all25%
  5. Iosco CountyBest late July · 509 checklists that week, 31,409 in all24%
  6. Chippewa CountyBest early August · 406 checklists that week, 28,128 in all22%

Best spots

Share of checklists at the peak
  1. New Buffalo Public BeachBerrien County, best mid April · 57 checklists that week, 2,934 in all90%
  2. Erie Marsh PreserveMonroe County, best late August · 170 checklists that week, 2,408 in all89%
  3. Tiscornia ParkBerrien County, best late April · 63 checklists that week, 3,628 in all88%
  4. Overlook ParkMidland County, best late August · 61 checklists that week, 2,020 in all85%
  5. Nayanquing Point State Wildlife AreaBay County, best mid May · 469 checklists that week, 3,152 in all83%
  6. North Bay ParkWashtenaw County, best mid August · 39 checklists that week, 2,958 in all82%

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

Best time of day

In Michigan, the Caspian Tern is most often listed on checklists started between 6 and 8 am (3.0% of those checklists).

0%1%2%3%4%12 am: too few checklists (712) to judge1 am: too few checklists (592) to judge2 am: too few checklists (532) to judge3 am: too few checklists (516) to judge4 am: too few checklists (1592) to judge5 am: too few checklists (6849) to judge6 am: 3.9% of 39298 checklists7 am: 2.7% of 120344 checklists8 am: 2.0% of 180109 checklists9 am: 1.9% of 171966 checklists10 am: 1.9% of 156332 checklists11 am: 1.9% of 134964 checklists12 pm: 1.9% of 120967 checklists1 pm: 2.0% of 113852 checklists2 pm: 2.0% of 110773 checklists3 pm: 1.9% of 105530 checklists4 pm: 1.8% of 100958 checklists5 pm: 2.1% of 80085 checklists6 pm: 2.4% of 62883 checklists7 pm: 2.4% of 44912 checklists8 pm: too few checklists (21062) to judge9 pm: too few checklists (5920) to judge10 pm: too few checklists (1629) to judge11 pm: too few checklists (775) 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%0%0%0%
February0%0%0%0%
March0%0%0.1%0.1%
April0.4%1.4%3.0%3.7%
May3.4%3.1%5.0%3.7%
June2.9%2.6%2.9%3.4%
July4.3%4.2%4.7%5.3%
August6.1%6.3%6.3%5.1%
September3.0%2.2%2.3%1.1%
October0.8%0.4%0.2%0.1%
November0.1%0.1%0%0%
December0%0.1%0%0%

Neighboring states

  • Ohio: arrives early April, 1 week earlier than Michigan
  • Indiana: arrives late March, 2 weeks earlier than Michigan
  • Illinois: arrives late March, 2 weeks earlier than Michigan
  • Wisconsin: arrives the second week of April, in the same week than Michigan

Common questions

When do Caspian Terns arrive in Michigan?
Caspian Terns reach Michigan in the second week of April, are common by mid April, peak in the second week of August (6.2% of checklists), and most are gone by the second week of September.
When do Caspian Terns leave Michigan?
Most Caspian Terns have left Michigan by the second week of September, when reports fall below half their usual rate. Stragglers are still reported until late September.
When is the best time to see a Caspian Tern in Michigan?
The Caspian Tern is reported most often in the second week of August, on about 6.2% of Michigan checklists.
Where in Michigan are Caspian Terns seen most often?
By county, Monroe County, Bay County, and Arenac County have the highest peak reporting rates for the Caspian Tern (counties with at least 200 checklists).