WhenToBird

Thalasseus maximus · Laridae

When Do Royal Terns Arrive in Louisiana?

Adult Royal Tern
Photo: Ricard Busquets Reverte, CC BY 4.0 via iNaturalist

Royal Terns are in Louisiana all year, but most are here in spring: numbers build from early April, peak in mid April (9.5% of checklists), and fall back by the second week of May. In the quietest week (late February) they are still on about 2.9% of checklists.

When to look

Numbers buildApr 1-7early April
PeakApr 15-21mid April
Fall back byMay 8-14the second week of May
FewestFeb 22-28late February

Best: mid April. Here all year; numbers build from early April and fall back by the second week of May. Peak: on about 9.5% of Louisiana checklists.

  1. Januncommon
  2. Febuncommon
  3. Marcommon
  4. Aprpeak season
  5. Maypeak season
  6. Juncommon
  7. Julcommon
  8. Augcommon
  9. Sepcommon
  10. Octcommon
  11. Novcommon
  12. Deccommon

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

0%5%10%15%Jan 1-7: 3.0% of 8384 checklistsJan 8-14: 3.8% of 6265 checklistsJan 15-21: 3.6% of 6825 checklistsJan 22-31: 3.7% of 8776 checklistsFeb 1-7: 3.8% of 5956 checklistsFeb 8-14: 3.0% of 6291 checklistsFeb 15-21: 3.0% of 8044 checklistsFeb 22-28: 2.9% of 5946 checklistsMar 1-7: 2.7% of 5981 checklistsMar 8-14: 3.3% of 6307 checklistsMar 15-21: 4.0% of 6747 checklistsMar 22-31: 4.4% of 10487 checklistsApr 1-7: 6.0% of 8037 checklistsApr 8-14: 8.4% of 9577 checklistsApr 15-21: 9.5% of 11372 checklistsApr 22-30: 10% of 14344 checklistsMay 1-7: 7.7% of 8193 checklistsMay 8-14: 5.7% of 6823 checklistsMay 15-21: 4.5% of 4818 checklistsMay 22-31: 4.9% of 6206 checklistsJun 1-7: 3.9% of 3660 checklistsJun 8-14: 3.6% of 3455 checklistsJun 15-21: 3.8% of 3084 checklistsJun 22-30: 4.2% of 3904 checklistsJul 1-7: 3.0% of 3240 checklistsJul 8-14: 5.3% of 3235 checklistsJul 15-21: 3.7% of 3167 checklistsJul 22-31: 4.8% of 4328 checklistsAug 1-7: 4.3% of 3192 checklistsAug 8-14: 4.8% of 3394 checklistsAug 15-21: 4.6% of 3502 checklistsAug 22-31: 7.1% of 5658 checklistsSep 1-7: 6.5% of 4366 checklistsSep 8-14: 6.2% of 4648 checklistsSep 15-21: 5.6% of 4369 checklistsSep 22-30: 6.0% of 6418 checklistsOct 1-7: 5.3% of 5375 checklistsOct 8-14: 6.7% of 6213 checklistsOct 15-21: 6.0% of 5553 checklistsOct 22-31: 6.9% of 8879 checklistsNov 1-7: 5.2% of 6231 checklistsNov 8-14: 5.7% of 5011 checklistsNov 15-21: 4.3% of 4856 checklistsNov 22-30: 4.1% of 6696 checklistsDec 1-7: 3.7% of 4530 checklistsDec 8-14: 3.9% of 4883 checklistsDec 15-21: 3.2% of 5833 checklistsDec 22-31: 3.5% of 9940 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 Louisiana 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 Louisiana

Best counties

Share of checklists at the peak
  1. Cameron ParishBest mid August · 112 checklists that week, 17,943 in all45%
  2. Plaquemines ParishBest early June · 27 checklists that week, 3,374 in all44%
  3. St. Bernard ParishBest mid May · 27 checklists that week, 1,331 in all35%
  4. Jefferson ParishBest early May · 813 checklists that week, 25,795 in all28%
  5. Lafourche ParishBest late April · 126 checklists that week, 4,021 in all19%
  6. St. John the Baptist ParishBest early August · 18 checklists that week, 957 in all17%

Best spots

Share of checklists at the peak
  1. Irish Bayou LagoonOrleans Parish, best late September · 24 checklists that week, 365 in all96%
  2. Bayou Thunder Von TrancJefferson Parish, best late April · 63 checklists that week, 675 in all87%

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

Best time of day

In Louisiana, the Royal Tern is most often listed on checklists started between 1 and 3 pm (6.7% of those checklists).

0%2%4%6%8%12 am: too few checklists (110) to judge1 am: too few checklists (95) to judge2 am: too few checklists (78) to judge3 am: too few checklists (145) to judge4 am: too few checklists (266) to judge5 am: too few checklists (2981) to judge6 am: 4.1% of 21115 checklists7 am: 4.7% of 38843 checklists8 am: 4.8% of 36306 checklists9 am: 5.4% of 31934 checklists10 am: 5.7% of 27208 checklists11 am: 6.3% of 20733 checklists12 pm: 6.2% of 18505 checklists1 pm: 6.7% of 17383 checklists2 pm: 6.6% of 17422 checklists3 pm: 5.5% of 17005 checklists4 pm: 4.9% of 17170 checklists5 pm: 4.0% of 12536 checklists6 pm: 3.8% of 8080 checklists7 pm: too few checklists (3798) to judge8 pm: too few checklists (676) to judge9 pm: too few checklists (311) to judge10 pm: too few checklists (206) to judge11 pm: too few checklists (93) 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
January3.0%3.8%3.6%3.7%
February3.8%3.0%3.0%2.9%
March2.7%3.3%4.0%4.4%
April6.0%8.4%9.5%10%
May7.7%5.7%4.5%4.9%
June3.9%3.6%3.8%4.2%
July3.0%5.3%3.7%4.8%
August4.3%4.8%4.6%7.1%
September6.5%6.2%5.6%6.0%
October5.3%6.7%6.0%6.9%
November5.2%5.7%4.3%4.1%
December3.7%3.9%3.2%3.5%

Neighboring states

  • Mississippi: year-round, peaks early September
  • Alabama: arrives mid August, 18 weeks later than Louisiana
  • Texas: arrives late March, 1 week earlier than Louisiana
  • Georgia: year-round, peaks the second week of July

Common questions

When do Royal Terns arrive in Louisiana?
Royal Terns are in Louisiana all year, but most are here in spring: numbers build from early April, peak in mid April (9.5% of checklists), and fall back by the second week of May. In the quietest week (late February) they are still on about 2.9% of checklists.
When do Royal Terns leave Louisiana?
Royal Terns never fully leave Louisiana: numbers fall back below half their usual rate by the second week of May, but some are still reported in every week, about 2.9% of checklists at the low.
When is the best time to see a Royal Tern in Louisiana?
The Royal Tern is reported most often in mid April, on about 9.5% of Louisiana checklists.
Where in Louisiana are Royal Terns seen most often?
By county, Cameron Parish, Plaquemines Parish, and St. Bernard Parish have the highest peak reporting rates for the Royal Tern (counties with at least 200 checklists).