WhenToBird

Gelochelidon nilotica · Laridae

When Do Gull-billed Terns Arrive in Alabama?

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

Gull-billed Terns arrive in Alabama in early April, peak in mid April (2.5% of checklists), and most are gone by the second week of August.

When to look

First arrivalsApr 1-7early April
Common byApr 1-7early April
PeakApr 15-21mid April
Most gone byAug 8-14the second week of August

Best: mid April. First arrivals early April; most are gone by the second week of August. Peak: on about 2.5% of Alabama checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Maruncommon
  4. Aprpeak season
  5. Maypeak season
  6. Junpeak season
  7. Julpeak season
  8. Augcommon
  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% of 8642 checklistsJan 8-14: 0% of 6607 checklistsJan 15-21: 0% of 6680 checklistsJan 22-31: 0% of 9008 checklistsFeb 1-7: 0% of 6642 checklistsFeb 8-14: 0% of 7568 checklistsFeb 15-21: 0% of 9929 checklistsFeb 22-28: 0% of 6490 checklistsMar 1-7: 0% of 6458 checklistsMar 8-14: 0.1% of 6570 checklistsMar 15-21: 0% of 6773 checklistsMar 22-31: 0.3% of 10830 checklistsApr 1-7: 1.1% of 8995 checklistsApr 8-14: 2.5% of 10390 checklistsApr 15-21: 2.7% of 12700 checklistsApr 22-30: 2.2% of 14225 checklistsMay 1-7: 2.3% of 9140 checklistsMay 8-14: 1.8% of 8111 checklistsMay 15-21: 1.6% of 6353 checklistsMay 22-31: 1.9% of 8318 checklistsJun 1-7: 1.5% of 5231 checklistsJun 8-14: 1.5% of 4757 checklistsJun 15-21: 1.8% of 4646 checklistsJun 22-30: 2.0% of 5740 checklistsJul 1-7: 1.9% of 4694 checklistsJul 8-14: 1.7% of 4178 checklistsJul 15-21: 2.0% of 4109 checklistsJul 22-31: 2.2% of 6000 checklistsAug 1-7: 1.5% of 4666 checklistsAug 8-14: 0.8% of 4468 checklistsAug 15-21: 0.7% of 4474 checklistsAug 22-31: 0.6% of 6494 checklistsSep 1-7: 0.4% of 5434 checklistsSep 8-14: 0.3% of 5216 checklistsSep 15-21: 0.3% of 5162 checklistsSep 22-30: 0.2% of 7474 checklistsOct 1-7: 0.1% of 6916 checklistsOct 8-14: 0.1% of 7332 checklistsOct 15-21: 0.1% of 6038 checklistsOct 22-31: 0.1% of 7071 checklistsNov 1-7: 0.1% of 5207 checklistsNov 8-14: 0% of 4883 checklistsNov 15-21: 0% of 5122 checklistsNov 22-30: 0% of 7130 checklistsDec 1-7: 0% of 4897 checklistsDec 8-14: 0% of 4738 checklistsDec 15-21: 0% of 5321 checklistsDec 22-31: 0% of 9158 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 Alabama 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 Alabama

Best counties

Share of checklists at the peak
  1. Mobile CountyBest the second week of July · 220 checklists that week, 34,270 in all20%
  2. Baldwin CountyBest mid July · 595 checklists that week, 54,971 in all6.4%

Best spots

Share of checklists at the peak
  1. Dauphin Island Public BeachMobile County, best early May · 31 checklists that week, 1,054 in all37%
  2. 5 Rivers Delta Resource CenterBaldwin County, best the second week of May · 24 checklists that week, 1,050 in all35%
  3. Meaher State ParkBaldwin County, best the second week of May · 27 checklists that week, 1,299 in all35%

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

Best time of day

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

0%0.5%1%1.5%2%12 am: too few checklists (109) to judge1 am: too few checklists (111) to judge2 am: too few checklists (112) to judge3 am: too few checklists (143) to judge4 am: too few checklists (303) to judge5 am: too few checklists (4125) to judge6 am: 1.8% of 26677 checklists7 am: 0.9% of 42599 checklists8 am: 0.8% of 39919 checklists9 am: 0.7% of 34699 checklists10 am: 0.7% of 28551 checklists11 am: 0.6% of 23505 checklists12 pm: 0.5% of 20345 checklists1 pm: 0.6% of 18964 checklists2 pm: 0.6% of 20110 checklists3 pm: 0.7% of 20685 checklists4 pm: 0.7% of 19041 checklists5 pm: 0.8% of 13807 checklists6 pm: 0.8% of 8507 checklists7 pm: too few checklists (3367) to judge8 pm: too few checklists (637) to judge9 pm: too few checklists (295) to judge10 pm: too few checklists (233) to judge11 pm: too few checklists (141) 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%0.1%0%0.3%
April1.1%2.5%2.7%2.2%
May2.3%1.8%1.6%1.9%
June1.5%1.5%1.8%2.0%
July1.9%1.7%2.0%2.2%
August1.5%0.8%0.7%0.6%
September0.4%0.3%0.3%0.2%
October0.1%0.1%0.1%0.1%
November0.1%0%0%0%
December0%0%0%0%

Neighboring states

  • Mississippi: arrives early April, in the same week than Alabama
  • Louisiana: arrives late March, 1 week earlier than Alabama
  • South Carolina: arrives mid April, 2 weeks later than Alabama
  • Texas: arrives early March, 4 weeks earlier than Alabama

Common questions

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