WhenToBird

Gygis candida · Laridae

When Do Blue-billed White-Terns Arrive in Hawaii?

Blue-billed White-Terns are in Hawaii all year, but most are here in summer: numbers build from the second week of April, peak in late July (7.7% of checklists), and fall back by late August. In the quietest week (the second week of December) they are still on about 3.0% of checklists.

When to look

Numbers buildApr 8-14the second week of April
PeakJul 22-31late July
Fall back byAug 22-31late August
FewestDec 8-14the second week of December

Best: late July. Here all year; numbers build from the second week of April and fall back by late August. Peak: on about 7.7% of Hawaii checklists.

  1. Jancommon
  2. Febcommon
  3. Marcommon
  4. Aprpeak season
  5. Maypeak season
  6. Junpeak season
  7. Julpeak season
  8. Augpeak season
  9. Sepcommon
  10. Octcommon
  11. Novcommon
  12. Deccommon

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

0%2%4%6%8%Jan 1-7: 3.8% of 5223 checklistsJan 8-14: 3.7% of 4322 checklistsJan 15-21: 3.5% of 4791 checklistsJan 22-31: 3.8% of 6113 checklistsFeb 1-7: 3.2% of 4916 checklistsFeb 8-14: 3.7% of 4778 checklistsFeb 15-21: 5.2% of 5119 checklistsFeb 22-28: 4.3% of 5246 checklistsMar 1-7: 5.0% of 4356 checklistsMar 8-14: 4.8% of 4127 checklistsMar 15-21: 4.6% of 4584 checklistsMar 22-31: 4.0% of 5941 checklistsApr 1-7: 5.3% of 3596 checklistsApr 8-14: 6.3% of 3301 checklistsApr 15-21: 6.2% of 3268 checklistsApr 22-30: 6.5% of 3732 checklistsMay 1-7: 5.4% of 2628 checklistsMay 8-14: 7.2% of 3151 checklistsMay 15-21: 6.8% of 2566 checklistsMay 22-31: 6.6% of 4054 checklistsJun 1-7: 6.8% of 2703 checklistsJun 8-14: 7.3% of 2731 checklistsJun 15-21: 7.9% of 2826 checklistsJun 22-30: 6.7% of 3671 checklistsJul 1-7: 5.9% of 2692 checklistsJul 8-14: 6.0% of 2734 checklistsJul 15-21: 8.0% of 2412 checklistsJul 22-31: 7.3% of 3581 checklistsAug 1-7: 7.9% of 2426 checklistsAug 8-14: 6.7% of 2669 checklistsAug 15-21: 5.2% of 2605 checklistsAug 22-31: 6.1% of 3159 checklistsSep 1-7: 5.3% of 2502 checklistsSep 8-14: 4.2% of 2975 checklistsSep 15-21: 4.4% of 3090 checklistsSep 22-30: 5.1% of 3424 checklistsOct 1-7: 4.6% of 2897 checklistsOct 8-14: 5.3% of 3420 checklistsOct 15-21: 4.7% of 3802 checklistsOct 22-31: 4.0% of 4531 checklistsNov 1-7: 3.9% of 3215 checklistsNov 8-14: 2.8% of 3704 checklistsNov 15-21: 3.8% of 3216 checklistsNov 22-30: 3.7% of 4153 checklistsDec 1-7: 3.4% of 3627 checklistsDec 8-14: 2.2% of 3710 checklistsDec 15-21: 3.4% of 3731 checklistsDec 22-31: 3.5% of 6597 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 Hawaii 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 Hawaii

Best counties

Share of checklists at the peak
  1. Northwestern Hawaiian Islands CountyBest late June · 14 checklists that week, 404 in all84%
  2. Honolulu CountyBest late July · 1009 checklists that week, 47,705 in all25%
  3. Hawaii CountyBest the second week of July · 1088 checklists that week, 75,146 in all0.3%
  4. Kauai CountyBest the second week of June · 476 checklists that week, 32,543 in all0.2%
  5. Maui CountyBest the second week of August · 334 checklists that week, 22,729 in all0.1%

Best spots

Share of checklists at the peak
  1. Fort DeRussy BeachHonolulu County, best late October · 23 checklists that week, 971 in all89%
  2. Kapiolani Regional ParkHonolulu County, best late June · 24 checklists that week, 1,486 in all84%
  3. Kaiwi State Scenic ShorelineHonolulu County, best late May · 20 checklists that week, 469 in all69%
  4. Green IslandNorthwestern Hawaiian Islands County, best late December · 35 checklists that week, 303 in all67%
  5. Ala Moana Regional ParkHonolulu County, best the second week of May · 22 checklists that week, 685 in all64%
  6. Koko Head Regional Park (Hālona Cove)Honolulu County, best mid April · 23 checklists that week, 571 in all59%

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

Best time of day

In Hawaii, the Blue-billed White-Tern is most often listed on checklists started between 6 and 8 am (7.0% of those checklists).

0%2%4%6%8%12 am: too few checklists (66) to judge1 am: too few checklists (53) to judge2 am: too few checklists (70) to judge3 am: too few checklists (68) to judge4 am: too few checklists (106) to judge5 am: too few checklists (1548) to judge6 am: 7.0% of 10237 checklists7 am: 7.0% of 17935 checklists8 am: 5.8% of 18565 checklists9 am: 5.1% of 19076 checklists10 am: 4.3% of 18179 checklists11 am: 4.2% of 15530 checklists12 pm: 4.1% of 13069 checklists1 pm: 3.5% of 12798 checklists2 pm: 3.3% of 12698 checklists3 pm: 3.4% of 12213 checklists4 pm: 4.4% of 10921 checklists5 pm: 5.7% of 9437 checklists6 pm: 5.8% of 4360 checklists7 pm: too few checklists (1028) to judge8 pm: too few checklists (316) to judge9 pm: too few checklists (182) to judge10 pm: too few checklists (110) to judge11 pm: too few checklists (50) 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
January3.8%3.7%3.5%3.8%
February3.2%3.7%5.2%4.3%
March5.0%4.8%4.6%4.0%
April5.3%6.3%6.2%6.5%
May5.4%7.2%6.8%6.6%
June6.8%7.3%7.9%6.7%
July5.9%6.0%8.0%7.3%
August7.9%6.7%5.2%6.1%
September5.3%4.2%4.4%5.1%
October4.6%5.3%4.7%4.0%
November3.9%2.8%3.8%3.7%
December3.4%2.2%3.4%3.5%

Common questions

When do Blue-billed White-Terns arrive in Hawaii?
Blue-billed White-Terns are in Hawaii all year, but most are here in summer: numbers build from the second week of April, peak in late July (7.7% of checklists), and fall back by late August. In the quietest week (the second week of December) they are still on about 3.0% of checklists.
When do Blue-billed White-Terns leave Hawaii?
Blue-billed White-Terns never fully leave Hawaii: numbers fall back below half their usual rate by late August, but some are still reported in every week, about 3.0% of checklists at the low.
When is the best time to see a Blue-billed White-Tern in Hawaii?
The Blue-billed White-Tern is reported most often in late July, on about 7.7% of Hawaii checklists.
Where in Hawaii are Blue-billed White-Terns seen most often?
By county, Northwestern Hawaiian Islands County, Honolulu County, and Hawaii County have the highest peak reporting rates for the Blue-billed White-Tern (counties with at least 200 checklists).