WhenToBird

Gelochelidon nilotica · Laridae

When Do Gull-billed Terns Arrive in South Carolina?

Adult Gull-billed Tern
Photo: datadan, CC BY 4.0 via iNaturalist

Gull-billed Terns arrive in South Carolina in mid April, peak in early July (2.5% of checklists), and most are gone by early September.

When to look

First arrivalsApr 15-21mid April
Common byApr 15-21mid April
PeakJul 1-7early July
Most gone bySep 1-7early September

Best: early July. First arrivals mid April; most are gone by early September. Peak: on about 2.5% of South Carolina checklists.

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

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

0%1%2%3%Jan 1-7: 0.1% of 15487 checklistsJan 8-14: 0.1% of 11691 checklistsJan 15-21: 0% of 11994 checklistsJan 22-31: 0.1% of 16225 checklistsFeb 1-7: 0.1% of 12192 checklistsFeb 8-14: 0.1% of 14044 checklistsFeb 15-21: 0.1% of 18483 checklistsFeb 22-28: 0.1% of 12045 checklistsMar 1-7: 0.1% of 11511 checklistsMar 8-14: 0.1% of 11704 checklistsMar 15-21: 0% of 11526 checklistsMar 22-31: 0.1% of 17386 checklistsApr 1-7: 0.4% of 13148 checklistsApr 8-14: 0.9% of 13193 checklistsApr 15-21: 1.3% of 13936 checklistsApr 22-30: 1.4% of 19002 checklistsMay 1-7: 1.4% of 14133 checklistsMay 8-14: 1.6% of 13668 checklistsMay 15-21: 1.8% of 11064 checklistsMay 22-31: 1.6% of 14461 checklistsJun 1-7: 2.1% of 10231 checklistsJun 8-14: 2.2% of 9417 checklistsJun 15-21: 2.4% of 8012 checklistsJun 22-30: 2.5% of 9720 checklistsJul 1-7: 2.3% of 7907 checklistsJul 8-14: 2.6% of 7338 checklistsJul 15-21: 2.1% of 7312 checklistsJul 22-31: 2.2% of 10877 checklistsAug 1-7: 2.2% of 7816 checklistsAug 8-14: 1.9% of 7655 checklistsAug 15-21: 1.9% of 7797 checklistsAug 22-31: 1.1% of 11246 checklistsSep 1-7: 0.9% of 8956 checklistsSep 8-14: 0.8% of 8929 checklistsSep 15-21: 0.6% of 9389 checklistsSep 22-30: 0.4% of 13028 checklistsOct 1-7: 0.2% of 11063 checklistsOct 8-14: 0.1% of 10968 checklistsOct 15-21: 0.1% of 10264 checklistsOct 22-31: 0% of 12917 checklistsNov 1-7: 0.1% of 8802 checklistsNov 8-14: 0% of 8339 checklistsNov 15-21: 0.1% of 8798 checklistsNov 22-30: 0.1% of 12925 checklistsDec 1-7: 0.1% of 8541 checklistsDec 8-14: 0.1% of 8609 checklistsDec 15-21: 0.1% of 9961 checklistsDec 22-31: 0.1% of 17541 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 South Carolina 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 South Carolina

Best counties

Share of checklists at the peak
  1. Jasper CountyBest late June · 286 checklists that week, 12,443 in all38%
  2. Colleton CountyBest the second week of May · 244 checklists that week, 8,909 in all10%
  3. Charleston CountyBest early July · 1429 checklists that week, 102,218 in all5.6%
  4. Georgetown CountyBest the second week of June · 632 checklists that week, 32,234 in all4.3%
  5. Beaufort CountyBest the second week of August · 780 checklists that week, 60,298 in all1.6%
  6. Horry CountyBest mid August · 381 checklists that week, 27,518 in all1.0%

Best spots

Share of checklists at the peak
  1. The CoveCharleston County, best late May · 84 checklists that week, 3,344 in all48%
  2. Bear Island Wildlife Management AreaColleton County, best the second week of May · 42 checklists that week, 1,645 in all41%
  3. Shem Creek BoardwalkCharleston County, best early July · 20 checklists that week, 854 in all32%
  4. Hog IslandCharleston County, best the second week of May · 20 checklists that week, 1,188 in all26%

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

Best time of day

In South Carolina, the Gull-billed Tern is most often listed on checklists started between 6 and 8 am (1.3% of those checklists).

0%1%2%3%12 am: too few checklists (222) to judge1 am: too few checklists (160) to judge2 am: too few checklists (132) to judge3 am: too few checklists (212) to judge4 am: too few checklists (267) to judge5 am: too few checklists (1898) to judge6 am: 2.1% of 19280 checklists7 am: 1.0% of 66492 checklists8 am: 0.9% of 73941 checklists9 am: 0.9% of 63039 checklists10 am: 0.7% of 52652 checklists11 am: 0.5% of 41908 checklists12 pm: 0.9% of 36782 checklists1 pm: 0.4% of 33300 checklists2 pm: 0.4% of 32248 checklists3 pm: 0.4% of 35451 checklists4 pm: 0.3% of 34410 checklists5 pm: 0.4% of 27073 checklists6 pm: 0.8% of 17375 checklists7 pm: too few checklists (10313) to judge8 pm: too few checklists (2756) to judge9 pm: too few checklists (672) to judge10 pm: too few checklists (412) 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
January0.1%0.1%0%0.1%
February0.1%0.1%0.1%0.1%
March0.1%0.1%0%0.1%
April0.4%0.9%1.3%1.4%
May1.4%1.6%1.8%1.6%
June2.1%2.2%2.4%2.5%
July2.3%2.6%2.1%2.2%
August2.2%1.9%1.9%1.1%
September0.9%0.8%0.6%0.4%
October0.2%0.1%0.1%0%
November0.1%0%0.1%0.1%
December0.1%0.1%0.1%0.1%

Neighboring states

  • Alabama: arrives early April, 2 weeks earlier than South Carolina
  • Mississippi: arrives early April, 2 weeks earlier than South Carolina
  • Louisiana: arrives late March, 3 weeks earlier than South Carolina
  • Texas: arrives early March, 6 weeks earlier than South Carolina

Common questions

When do Gull-billed Terns arrive in South Carolina?
Gull-billed Terns arrive in South Carolina in mid April, peak in early July (2.5% of checklists), and most are gone by early September.
When do Gull-billed Terns leave South Carolina?
Most Gull-billed Terns have left South Carolina by early September, when reports fall below half their usual rate.
When is the best time to see a Gull-billed Tern in South Carolina?
The Gull-billed Tern is reported most often in early July, on about 2.5% of South Carolina checklists.
Where in South Carolina are Gull-billed Terns seen most often?
By county, Jasper County, Colleton County, and Charleston County have the highest peak reporting rates for the Gull-billed Tern (counties with at least 200 checklists).