WhenToBird

Sterna forsteri · Laridae

When Do Forster's Terns Arrive in Maryland?

Adult Forster's Tern
Photo: Aitor, CC BY 4.0 via iNaturalist

Forster's Terns reach Maryland in late March, are common by early April, peak in the second week of August (7.8% of checklists), and most are gone by late November.

When to look

First arrivalsMar 22-31late March
Common byApr 1-7early April
PeakAug 8-14the second week of August
Most gone byNov 22-30late November

Best: the second week of August. First arrivals late March; most are gone by late November. Peak: on about 7.8% of Maryland checklists.

  1. Janrare
  2. Febnot usually seen
  3. Maruncommon
  4. Apruncommon
  5. Mayuncommon
  6. Jununcommon
  7. Julpeak season
  8. Augpeak season
  9. Seppeak season
  10. Octcommon
  11. Novcommon
  12. Decuncommon

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

0%2%4%6%8%Jan 1-7: 0.4% of 28716 checklistsJan 8-14: 0.3% of 21449 checklistsJan 15-21: 0.2% of 21267 checklistsJan 22-31: 0.1% of 29144 checklistsFeb 1-7: 0.2% of 21347 checklistsFeb 8-14: 0.1% of 22166 checklistsFeb 15-21: 0.3% of 29986 checklistsFeb 22-28: 0.3% of 22427 checklistsMar 1-7: 0.4% of 21389 checklistsMar 8-14: 0.4% of 22192 checklistsMar 15-21: 0.7% of 22823 checklistsMar 22-31: 1.2% of 33720 checklistsApr 1-7: 2.5% of 25513 checklistsApr 8-14: 3.0% of 27718 checklistsApr 15-21: 3.4% of 29328 checklistsApr 22-30: 2.9% of 42595 checklistsMay 1-7: 2.0% of 38532 checklistsMay 8-14: 1.7% of 42722 checklistsMay 15-21: 1.6% of 31936 checklistsMay 22-31: 1.3% of 36903 checklistsJun 1-7: 1.0% of 23191 checklistsJun 8-14: 1.2% of 21853 checklistsJun 15-21: 1.1% of 21000 checklistsJun 22-30: 1.6% of 25133 checklistsJul 1-7: 2.2% of 18715 checklistsJul 8-14: 3.3% of 16376 checklistsJul 15-21: 4.9% of 15793 checklistsJul 22-31: 6.2% of 21969 checklistsAug 1-7: 7.9% of 16013 checklistsAug 8-14: 7.8% of 15249 checklistsAug 15-21: 7.9% of 15674 checklistsAug 22-31: 6.6% of 24925 checklistsSep 1-7: 5.9% of 19808 checklistsSep 8-14: 5.1% of 18513 checklistsSep 15-21: 5.5% of 21901 checklistsSep 22-30: 4.9% of 22901 checklistsOct 1-7: 4.8% of 19111 checklistsOct 8-14: 4.5% of 18482 checklistsOct 15-21: 4.6% of 17380 checklistsOct 22-31: 4.7% of 23992 checklistsNov 1-7: 4.0% of 17915 checklistsNov 8-14: 4.8% of 18905 checklistsNov 15-21: 2.8% of 16259 checklistsNov 22-30: 2.2% of 22852 checklistsDec 1-7: 0.9% of 16108 checklistsDec 8-14: 0.5% of 16512 checklistsDec 15-21: 0.3% of 18952 checklistsDec 22-31: 0.8% of 29728 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 Maryland 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 Maryland

Best counties

Share of checklists at the peak
  1. Queen Anne's CountyBest early August · 590 checklists that week, 26,875 in all35%
  2. Worcester CountyBest mid August · 643 checklists that week, 44,596 in all32%
  3. Calvert CountyBest early August · 690 checklists that week, 43,807 in all32%
  4. Dorchester CountyBest early October · 283 checklists that week, 26,161 in all30%
  5. Somerset CountyBest mid April · 292 checklists that week, 9,451 in all29%
  6. Talbot CountyBest the second week of August · 449 checklists that week, 31,140 in all26%

Best spots

Share of checklists at the peak
  1. Lynwood T Kellam Memorial Recreational ParkCalvert County, best early July · 24 checklists that week, 375 in all93%
  2. Hog PointCalvert County, best the second week of August · 69 checklists that week, 2,927 in all86%
  3. Sinepuxent Bay WmaWorcester County, best late September · 27 checklists that week, 995 in all86%
  4. Park IslandHarford County, best mid October · 24 checklists that week, 1,069 in all84%
  5. Sedgewick CoveQueen Anne's County, best early August · 66 checklists that week, 3,164 in all84%

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

Best time of day

In Maryland, the Forster's Tern is most often listed on checklists started between 6 and 8 am (3.1% of those checklists).

0%2%4%6%12 am: too few checklists (486) to judge1 am: too few checklists (451) to judge2 am: too few checklists (447) to judge3 am: too few checklists (766) to judge4 am: too few checklists (2076) to judge5 am: too few checklists (11098) to judge6 am: 4.5% of 56604 checklists7 am: 2.6% of 139255 checklists8 am: 2.2% of 148626 checklists9 am: 2.3% of 126820 checklists10 am: 2.2% of 106973 checklists11 am: 2.3% of 87483 checklists12 pm: 2.4% of 74808 checklists1 pm: 2.3% of 69428 checklists2 pm: 2.4% of 67800 checklists3 pm: 2.3% of 67688 checklists4 pm: 2.3% of 60927 checklists5 pm: 2.9% of 43876 checklists6 pm: 2.9% of 32930 checklists7 pm: too few checklists (19051) to judge8 pm: too few checklists (5708) to judge9 pm: too few checklists (1977) to judge10 pm: too few checklists (1170) to judge11 pm: too few checklists (635) 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
January0.4%0.3%0.2%0.1%
February0.2%0.1%0.3%0.3%
March0.4%0.4%0.7%1.2%
April2.5%3.0%3.4%2.9%
May2.0%1.7%1.6%1.3%
June1.0%1.2%1.1%1.6%
July2.2%3.3%4.9%6.2%
August7.9%7.8%7.9%6.6%
September5.9%5.1%5.5%4.9%
October4.8%4.5%4.6%4.7%
November4.0%4.8%2.8%2.2%
December0.9%0.5%0.3%0.8%

Neighboring states

  • District of Columbia: arrives early August, 17 weeks later than Maryland
  • Delaware: arrives the second week of March, 2 weeks earlier than Maryland
  • Virginia: arrives the second week of March, 2 weeks earlier than Maryland
  • New Jersey: arrives late March, in the same week than Maryland

Common questions

When do Forster's Terns arrive in Maryland?
Forster's Terns reach Maryland in late March, are common by early April, peak in the second week of August (7.8% of checklists), and most are gone by late November.
When do Forster's Terns leave Maryland?
Most Forster's Terns have left Maryland by late November, when reports fall below half their usual rate. Stragglers are still reported until early December.
When is the best time to see a Forster's Tern in Maryland?
The Forster's Tern is reported most often in the second week of August, on about 7.8% of Maryland checklists.
Where in Maryland are Forster's Terns seen most often?
By county, Queen Anne's County, Worcester County, and Calvert County have the highest peak reporting rates for the Forster's Tern (counties with at least 200 checklists).