WhenToBird

Sterna forsteri · Laridae

When Do Forster's Terns Arrive in District of Columbia?

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

Forster's Terns mostly pass through District of Columbia: they arrive in early August, peak in early September (3.0% of checklists), and most are gone by mid September.

When to look

First arrivalsAug 1-7early August
Common byAug 1-7early August
PeakSep 1-7early September
Most gone bySep 15-21mid September

Best: early September. First arrivals early August; most are gone by mid September. Peak: on about 3.0% of District of Columbia checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Marnot usually seen
  4. Aprnot usually seen
  5. Maynot usually seen
  6. Junnot usually seen
  7. Juluncommon
  8. Augpeak season
  9. Seppeak season
  10. Octuncommon
  11. Novnot usually seen
  12. Decnot usually seen

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

0%1%2%3%4%Jan 1-7: 0% of 3043 checklistsJan 8-14: 0% of 2367 checklistsJan 15-21: 0% of 2140 checklistsJan 22-31: 0% of 2777 checklistsFeb 1-7: 0% of 2012 checklistsFeb 8-14: 0% of 1997 checklistsFeb 15-21: 0% of 2544 checklistsFeb 22-28: 0% of 2252 checklistsMar 1-7: 0% of 2282 checklistsMar 8-14: 0% of 2350 checklistsMar 15-21: 0% of 2432 checklistsMar 22-31: 0% of 3898 checklistsApr 1-7: 0% of 3221 checklistsApr 8-14: 0.3% of 3396 checklistsApr 15-21: 0.1% of 3718 checklistsApr 22-30: 0.1% of 5725 checklistsMay 1-7: 0.1% of 5415 checklistsMay 8-14: 0.1% of 5268 checklistsMay 15-21: 0.1% of 3741 checklistsMay 22-31: 0% of 3605 checklistsJun 1-7: 0% of 1902 checklistsJun 8-14: 0.1% of 1762 checklistsJun 15-21: 0% of 1637 checklistsJun 22-30: 0% of 1727 checklistsJul 1-7: 0% of 1471 checklistsJul 8-14: 0% of 1353 checklistsJul 15-21: 0.1% of 1297 checklistsJul 22-31: 0.3% of 1980 checklistsAug 1-7: 1.7% of 1465 checklistsAug 8-14: 2.3% of 1311 checklistsAug 15-21: 1.9% of 1669 checklistsAug 22-31: 2.8% of 2631 checklistsSep 1-7: 3.7% of 2482 checklistsSep 8-14: 2.7% of 2622 checklistsSep 15-21: 1.1% of 2661 checklistsSep 22-30: 0.3% of 3393 checklistsOct 1-7: 0.8% of 2457 checklistsOct 8-14: 1.0% of 2487 checklistsOct 15-21: 0.1% of 2201 checklistsOct 22-31: 0.2% of 2639 checklistsNov 1-7: 0.1% of 2074 checklistsNov 8-14: 0% of 1967 checklistsNov 15-21: 0% of 1832 checklistsNov 22-30: 0.1% of 2064 checklistsDec 1-7: 0% of 1773 checklistsDec 8-14: 0% of 2132 checklistsDec 15-21: 0% of 2009 checklistsDec 22-31: 0% of 2574 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 District of Columbia 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 District of Columbia

Best counties

Share of checklists at the peak
  1. District of Columbia CountyBest early September · 2481 checklists that week, 121,721 in all3.0%

Best spots

Share of checklists at the peak
  1. Goose IslandDistrict of Columbia County, best late August · 31 checklists that week, 403 in all83%
  2. George Washington Memorial ParkwayDistrict of Columbia County, best late August · 50 checklists that week, 1,054 in all43%
  3. National Capital ParksDistrict of Columbia County, best late September · 75 checklists that week, 6,880 in all8.3%

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

Best time of day

In District of Columbia, the Forster's Tern is most often listed on checklists started between 5 and 7 pm (0.6% of those checklists).

0%0.5%1%12 am: too few checklists (27) to judge1 am: too few checklists (29) to judge2 am: too few checklists (23) to judge3 am: too few checklists (21) to judge4 am: too few checklists (31) to judge5 am: too few checklists (631) to judge6 am: 0.4% of 7391 checklists7 am: 0.2% of 18497 checklists8 am: 0.2% of 18527 checklists9 am: 0.4% of 13285 checklists10 am: 0.4% of 10722 checklists11 am: 0.4% of 8880 checklists12 pm: 0.4% of 7456 checklists1 pm: 0.4% of 6394 checklists2 pm: 0.3% of 6063 checklists3 pm: 0.5% of 6112 checklists4 pm: 0.4% of 5809 checklists5 pm: 0.7% of 5409 checklists6 pm: 0.5% of 3982 checklists7 pm: too few checklists (1887) to judge8 pm: too few checklists (423) to judge9 pm: too few checklists (79) to judge10 pm: too few checklists (44) to judge11 pm: too few checklists (33) 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%0%
April0%0.3%0.1%0.1%
May0.1%0.1%0.1%0%
June0%0.1%0%0%
July0%0%0.1%0.3%
August1.7%2.3%1.9%2.8%
September3.7%2.7%1.1%0.3%
October0.8%1.0%0.1%0.2%
November0.1%0%0%0.1%
December0%0%0%0%

Neighboring states

  • Maryland: arrives late March, 17 weeks earlier than District of Columbia
  • Virginia: arrives the second week of March, 19 weeks earlier than District of Columbia
  • Delaware: arrives the second week of March, 19 weeks earlier than District of Columbia
  • New Jersey: arrives late March, 17 weeks earlier than District of Columbia

Common questions

When do Forster's Terns arrive in District of Columbia?
Forster's Terns mostly pass through District of Columbia: they arrive in early August, peak in early September (3.0% of checklists), and most are gone by mid September.
When do Forster's Terns leave District of Columbia?
Most Forster's Terns have left District of Columbia by mid September, when reports fall below half their usual rate.
When is the best time to see a Forster's Tern in District of Columbia?
The Forster's Tern is reported most often in early September, on about 3.0% of District of Columbia checklists.
Where in District of Columbia are Forster's Terns seen most often?
By county, District of Columbia County have the highest peak reporting rates for the Forster's Tern (counties with at least 200 checklists).