WhenToBird

Setophaga castanea · Parulidae

When Do Bay-breasted Warblers Arrive in Kentucky?

Adult Bay-breasted Warbler
Photo: Roger A. Morales-Flores, CC BY 4.0 via iNaturalist

Bay-breasted Warblers mostly pass through Kentucky: the first show up in late August, they are common by early September, peak in late September (16% of checklists), and most are gone by mid October.

When to look

First arrivalsAug 22-31late August
Common bySep 1-7early September
PeakSep 22-30late September
Most gone byOct 15-21mid October

Best: late September. First arrivals late August; most are gone by mid October. Peak: on about 16% of Kentucky checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Marnot usually seen
  4. Aprrare
  5. Mayuncommon
  6. Junnot usually seen
  7. Julnot usually seen
  8. Augrare
  9. Seppeak season
  10. Octpeak season
  11. Novnot usually seen
  12. Decnot usually seen

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

0%5%10%15%20%Jan 1-7: 0% of 6923 checklistsJan 8-14: 0% of 4900 checklistsJan 15-21: 0% of 5016 checklistsJan 22-31: 0% of 6611 checklistsFeb 1-7: 0% of 4986 checklistsFeb 8-14: 0% of 5677 checklistsFeb 15-21: 0% of 8880 checklistsFeb 22-28: 0% of 5567 checklistsMar 1-7: 0% of 5397 checklistsMar 8-14: 0% of 5462 checklistsMar 15-21: 0% of 5733 checklistsMar 22-31: 0% of 9043 checklistsApr 1-7: 0% of 6763 checklistsApr 8-14: 0% of 7498 checklistsApr 15-21: 0.1% of 8486 checklistsApr 22-30: 0.9% of 13396 checklistsMay 1-7: 5.6% of 10825 checklistsMay 8-14: 7.8% of 11495 checklistsMay 15-21: 5.2% of 7363 checklistsMay 22-31: 0.5% of 8800 checklistsJun 1-7: 0% of 5381 checklistsJun 8-14: 0% of 5244 checklistsJun 15-21: 0% of 4730 checklistsJun 22-30: 0% of 5470 checklistsJul 1-7: 0% of 4567 checklistsJul 8-14: 0% of 4287 checklistsJul 15-21: 0% of 4097 checklistsJul 22-31: 0% of 6044 checklistsAug 1-7: 0% of 4647 checklistsAug 8-14: 0% of 4256 checklistsAug 15-21: 0.1% of 4484 checklistsAug 22-31: 0.9% of 6434 checklistsSep 1-7: 5.8% of 5450 checklistsSep 8-14: 9.9% of 5157 checklistsSep 15-21: 14% of 5530 checklistsSep 22-30: 18% of 6710 checklistsOct 1-7: 17% of 5403 checklistsOct 8-14: 8.5% of 5943 checklistsOct 15-21: 2.5% of 4873 checklistsOct 22-31: 0.3% of 6584 checklistsNov 1-7: 0.1% of 5008 checklistsNov 8-14: 0% of 4677 checklistsNov 15-21: 0% of 4419 checklistsNov 22-30: 0% of 5933 checklistsDec 1-7: 0% of 4479 checklistsDec 8-14: 0% of 4687 checklistsDec 15-21: 0% of 6239 checklistsDec 22-31: 0% of 7976 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 Kentucky 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 Kentucky

Best counties

Share of checklists at the peak
  1. Muhlenberg CountyBest late September · 22 checklists that week, 1,263 in all55%
  2. McCreary CountyBest early October · 15 checklists that week, 847 in all45%
  3. Harlan CountyBest mid September · 16 checklists that week, 318 in all40%
  4. Spencer CountyBest late September · 202 checklists that week, 7,721 in all39%
  5. Mercer CountyBest late September · 38 checklists that week, 1,919 in all33%
  6. Scott CountyBest mid September · 61 checklists that week, 2,526 in all31%

Best spots

Share of checklists at the peak
  1. Floracliff Nature SanctuaryFayette County, best early October · 26 checklists that week, 730 in all56%
  2. Big Bone Lick State Historic SiteBoone County, best the second week of September · 28 checklists that week, 474 in all56%
  3. Lexington CemeteryFayette County, best the second week of May · 180 checklists that week, 1,748 in all55%
  4. University of Kentucky & Lexington-Fayette Urban County Government ArboretumFayette County, best early October · 53 checklists that week, 2,100 in all49%
  5. Willow LakeJefferson County, best mid September · 76 checklists that week, 1,890 in all47%
  6. Caperton SwampJefferson County, best mid September · 47 checklists that week, 1,161 in all42%

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

Best time of day

In Kentucky, the Bay-breasted Warbler is most often listed on checklists started between 7 and 9 am (3.6% of those checklists).

0%1%2%3%4%12 am: too few checklists (140) to judge1 am: too few checklists (120) to judge2 am: too few checklists (88) to judge3 am: too few checklists (95) to judge4 am: too few checklists (151) to judge5 am: too few checklists (1289) to judge6 am: 2.0% of 8227 checklists7 am: 3.2% of 24608 checklists8 am: 3.8% of 36577 checklists9 am: 3.0% of 34626 checklists10 am: 2.1% of 28796 checklists11 am: 2.0% of 22781 checklists12 pm: 1.7% of 19848 checklists1 pm: 1.6% of 19369 checklists2 pm: 1.4% of 19367 checklists3 pm: 1.3% of 19618 checklists4 pm: 1.4% of 19464 checklists5 pm: 1.7% of 16639 checklists6 pm: 1.5% of 12714 checklists7 pm: 0.7% of 8457 checklists8 pm: too few checklists (3447) to judge9 pm: too few checklists (684) to judge10 pm: too few checklists (267) to judge11 pm: too few checklists (158) 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%0%0%
April0%0%0.1%0.9%
May5.6%7.8%5.2%0.5%
June0%0%0%0%
July0%0%0%0%
August0%0%0.1%0.9%
September5.8%9.9%14%18%
October17%8.5%2.5%0.3%
November0.1%0%0%0%
December0%0%0%0%

Neighboring states

  • Tennessee: arrives early September, 1 week later than Kentucky
  • Indiana: arrives mid August, 1 week earlier than Kentucky
  • Ohio: arrives mid August, 1 week earlier than Kentucky
  • Illinois: arrives mid August, 1 week earlier than Kentucky

Common questions

When do Bay-breasted Warblers arrive in Kentucky?
Bay-breasted Warblers mostly pass through Kentucky: the first show up in late August, they are common by early September, peak in late September (16% of checklists), and most are gone by mid October.
When do Bay-breasted Warblers leave Kentucky?
Most Bay-breasted Warblers have left Kentucky by mid October, when reports fall below half their usual rate.
When is the best time to see a Bay-breasted Warbler in Kentucky?
The Bay-breasted Warbler is reported most often in late September, on about 16% of Kentucky checklists.
Where in Kentucky are Bay-breasted Warblers seen most often?
By county, Muhlenberg County, McCreary County, and Harlan County have the highest peak reporting rates for the Bay-breasted Warbler (counties with at least 200 checklists).