WhenToBird

Horornis diphone · Cettiidae

When Do Japanese Bush Warblers Arrive in Hawaii?

Japanese Bush Warblers reach Hawaii in early October, are common by mid November, peak in early June (7.5% of checklists), and most are gone by mid July.

When to look

First arrivalsOct 1-7early October
Common byNov 15-21mid November
PeakJun 1-7early June
Most gone byJul 15-21mid July

Best: early June. First arrivals early October; most are gone by mid July. Peak: on about 7.5% of Hawaii checklists.

  1. Jancommon
  2. Febpeak season
  3. Marpeak season
  4. Aprpeak season
  5. Maypeak season
  6. Junpeak season
  7. Julpeak season
  8. Auguncommon
  9. Sepuncommon
  10. Octuncommon
  11. Novcommon
  12. Deccommon

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

0%5%10%Jan 1-7: 4.3% of 5223 checklistsJan 8-14: 4.3% of 4322 checklistsJan 15-21: 4.8% of 4791 checklistsJan 22-31: 4.9% of 6113 checklistsFeb 1-7: 5.6% of 4916 checklistsFeb 8-14: 5.7% of 4778 checklistsFeb 15-21: 6.0% of 5119 checklistsFeb 22-28: 6.1% of 5246 checklistsMar 1-7: 6.6% of 4356 checklistsMar 8-14: 6.0% of 4127 checklistsMar 15-21: 8.2% of 4584 checklistsMar 22-31: 6.7% of 5941 checklistsApr 1-7: 6.3% of 3596 checklistsApr 8-14: 7.0% of 3301 checklistsApr 15-21: 6.9% of 3268 checklistsApr 22-30: 6.4% of 3732 checklistsMay 1-7: 5.7% of 2628 checklistsMay 8-14: 7.8% of 3151 checklistsMay 15-21: 6.6% of 2566 checklistsMay 22-31: 7.6% of 4054 checklistsJun 1-7: 7.3% of 2703 checklistsJun 8-14: 7.7% of 2731 checklistsJun 15-21: 6.5% of 2826 checklistsJun 22-30: 6.3% of 3671 checklistsJul 1-7: 8.2% of 2692 checklistsJul 8-14: 6.8% of 2734 checklistsJul 15-21: 3.4% of 2412 checklistsJul 22-31: 2.8% of 3581 checklistsAug 1-7: 1.2% of 2426 checklistsAug 8-14: 1.1% of 2669 checklistsAug 15-21: 0.7% of 2605 checklistsAug 22-31: 1.1% of 3159 checklistsSep 1-7: 1.3% of 2502 checklistsSep 8-14: 1.0% of 2975 checklistsSep 15-21: 0.7% of 3090 checklistsSep 22-30: 1.0% of 3424 checklistsOct 1-7: 1.2% of 2897 checklistsOct 8-14: 1.9% of 3420 checklistsOct 15-21: 2.4% of 3802 checklistsOct 22-31: 2.5% of 4531 checklistsNov 1-7: 2.7% of 3215 checklistsNov 8-14: 2.8% of 3704 checklistsNov 15-21: 2.5% of 3216 checklistsNov 22-30: 3.6% of 4153 checklistsDec 1-7: 3.0% of 3627 checklistsDec 8-14: 2.8% of 3710 checklistsDec 15-21: 3.4% of 3731 checklistsDec 22-31: 3.9% 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. Kauai CountyBest mid May · 462 checklists that week, 32,543 in all18%
  2. Maui CountyBest mid March · 677 checklists that week, 22,729 in all8.2%
  3. Hawaii CountyBest the second week of March · 1622 checklists that week, 75,146 in all7.7%
  4. Honolulu CountyBest early June · 805 checklists that week, 47,705 in all3.0%

Best spots

Share of checklists at the peak
  1. Ka'ohe State LeaseHawaii County, best the second week of March · 37 checklists that week, 1,290 in all74%
  2. Koke'e State ParkKauai County, best early April · 22 checklists that week, 556 in all57%
  3. Waiokapua BayKauai County, best early April · 33 checklists that week, 1,614 in all41%
  4. Hawai'i Volcanoes National Park (Twin Craters)Hawaii County, best late March · 38 checklists that week, 729 in all41%
  5. Hawai'i Volcanoes National ParkHawaii County, best mid March · 35 checklists that week, 1,055 in all35%

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

Best time of day

In Hawaii, the Japanese Bush Warbler is most often listed on checklists started between 8 and 10 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: 4.2% of 10237 checklists7 am: 5.3% of 17935 checklists8 am: 7.3% of 18565 checklists9 am: 6.7% of 19076 checklists10 am: 5.6% of 18179 checklists11 am: 4.7% of 15530 checklists12 pm: 3.9% of 13069 checklists1 pm: 3.5% of 12798 checklists2 pm: 3.2% of 12698 checklists3 pm: 2.6% of 12213 checklists4 pm: 2.6% of 10921 checklists5 pm: 2.8% of 9437 checklists6 pm: 2.3% 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
January4.3%4.3%4.8%4.9%
February5.6%5.7%6.0%6.1%
March6.6%6.0%8.2%6.7%
April6.3%7.0%6.9%6.4%
May5.7%7.8%6.6%7.6%
June7.3%7.7%6.5%6.3%
July8.2%6.8%3.4%2.8%
August1.2%1.1%0.7%1.1%
September1.3%1.0%0.7%1.0%
October1.2%1.9%2.4%2.5%
November2.7%2.8%2.5%3.6%
December3.0%2.8%3.4%3.9%

Common questions

When do Japanese Bush Warblers arrive in Hawaii?
Japanese Bush Warblers reach Hawaii in early October, are common by mid November, peak in early June (7.5% of checklists), and most are gone by mid July.
When do Japanese Bush Warblers leave Hawaii?
Most Japanese Bush Warblers have left Hawaii by mid July, when reports fall below half their usual rate. Stragglers are still reported until early August.
When is the best time to see a Japanese Bush Warbler in Hawaii?
The Japanese Bush Warbler is reported most often in early June, on about 7.5% of Hawaii checklists.
Where in Hawaii are Japanese Bush Warblers seen most often?
By county, Kauai County, Maui County, and Hawaii County have the highest peak reporting rates for the Japanese Bush Warbler (counties with at least 200 checklists).