WhenToBird

Setophaga castanea · Parulidae

When Do Bay-breasted Warblers Arrive in Michigan?

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

Bay-breasted Warblers mostly pass through Michigan: they arrive in the second week of August, peak in the second week of September (11% of checklists), and most are gone by early October.

When to look

First arrivalsAug 8-14the second week of August
Common byAug 8-14the second week of August
PeakSep 8-14the second week of September
Most gone byOct 1-7early October

Best: the second week of September. First arrivals the second week of August; most are gone by early October. Peak: on about 11% of Michigan checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Marnot usually seen
  4. Aprnot usually seen
  5. Maycommon
  6. Junrare
  7. Julnot usually seen
  8. Augcommon
  9. Seppeak season
  10. Octuncommon
  11. Novnot usually seen
  12. Decnot usually seen

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

0%5%10%15%Jan 1-7: 0% of 38160 checklistsJan 8-14: 0% of 24696 checklistsJan 15-21: 0% of 23771 checklistsJan 22-31: 0% of 31347 checklistsFeb 1-7: 0% of 23225 checklistsFeb 8-14: 0% of 27398 checklistsFeb 15-21: 0% of 36606 checklistsFeb 22-28: 0% of 27127 checklistsMar 1-7: 0% of 29700 checklistsMar 8-14: 0% of 31587 checklistsMar 15-21: 0% of 32118 checklistsMar 22-31: 0% of 47777 checklistsApr 1-7: 0% of 38557 checklistsApr 8-14: 0% of 42207 checklistsApr 15-21: 0% of 42759 checklistsApr 22-30: 0.1% of 64458 checklistsMay 1-7: 0.4% of 60998 checklistsMay 8-14: 3.4% of 72091 checklistsMay 15-21: 7.5% of 59058 checklistsMay 22-31: 2.4% of 64724 checklistsJun 1-7: 0.1% of 35990 checklistsJun 8-14: 0.1% of 32595 checklistsJun 15-21: 0.1% of 30017 checklistsJun 22-30: 0.1% of 33988 checklistsJul 1-7: 0.1% of 28708 checklistsJul 8-14: 0.1% of 25175 checklistsJul 15-21: 0.1% of 24084 checklistsJul 22-31: 0.1% of 33522 checklistsAug 1-7: 0.1% of 25098 checklistsAug 8-14: 0.5% of 24353 checklistsAug 15-21: 2.3% of 25059 checklistsAug 22-31: 6.7% of 37489 checklistsSep 1-7: 11% of 28410 checklistsSep 8-14: 12% of 27887 checklistsSep 15-21: 9.2% of 26614 checklistsSep 22-30: 5.2% of 32557 checklistsOct 1-7: 1.2% of 25844 checklistsOct 8-14: 0.2% of 27741 checklistsOct 15-21: 0.1% of 24693 checklistsOct 22-31: 0.1% of 32460 checklistsNov 1-7: 0% of 23660 checklistsNov 8-14: 0% of 21542 checklistsNov 15-21: 0% of 19922 checklistsNov 22-30: 0% of 25069 checklistsDec 1-7: 0% of 18272 checklistsDec 8-14: 0% of 18961 checklistsDec 15-21: 0% of 24171 checklistsDec 22-31: 0% of 30908 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 Michigan 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 Michigan

Best counties

Share of checklists at the peak
  1. Ogemaw CountyBest the second week of September · 88 checklists that week, 4,675 in all25%
  2. Washtenaw CountyBest the second week of September · 2378 checklists that week, 145,231 in all20%
  3. Livingston CountyBest the second week of September · 594 checklists that week, 31,033 in all20%
  4. Macomb CountyBest the second week of September · 952 checklists that week, 61,232 in all19%
  5. St. Joseph CountyBest the second week of September · 112 checklists that week, 6,972 in all19%
  6. Monroe CountyBest the second week of September · 229 checklists that week, 22,078 in all17%

Best spots

Share of checklists at the peak
  1. Hudson Mills MetroparkWashtenaw County, best the second week of September · 42 checklists that week, 1,136 in all64%
  2. Burchfield Park and Nature AreaIngham County, best the second week of September · 24 checklists that week, 350 in all64%
  3. Elizabeth ParkWayne County, best late August · 40 checklists that week, 771 in all61%
  4. Cherry Hill Nature PreserveWashtenaw County, best early September · 114 checklists that week, 980 in all58%
  5. Arboretum Nature AreaWashtenaw County, best the second week of September · 293 checklists that week, 6,118 in all57%

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

Best time of day

In Michigan, the Bay-breasted Warbler is most often listed on checklists started between 6 and 8 am (2.9% of those checklists).

0%1%2%3%4%12 am: too few checklists (712) to judge1 am: too few checklists (592) to judge2 am: too few checklists (532) to judge3 am: too few checklists (516) to judge4 am: too few checklists (1592) to judge5 am: too few checklists (6849) to judge6 am: 2.4% of 39298 checklists7 am: 3.1% of 120344 checklists8 am: 2.5% of 180109 checklists9 am: 1.8% of 171966 checklists10 am: 1.3% of 156332 checklists11 am: 1.1% of 134964 checklists12 pm: 1.0% of 120967 checklists1 pm: 0.9% of 113852 checklists2 pm: 0.9% of 110773 checklists3 pm: 0.8% of 105530 checklists4 pm: 1.0% of 100958 checklists5 pm: 1.2% of 80085 checklists6 pm: 1.2% of 62883 checklists7 pm: 0.6% of 44912 checklists8 pm: too few checklists (21062) to judge9 pm: too few checklists (5920) to judge10 pm: too few checklists (1629) to judge11 pm: too few checklists (775) 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%0.1%
May0.4%3.4%7.5%2.4%
June0.1%0.1%0.1%0.1%
July0.1%0.1%0.1%0.1%
August0.1%0.5%2.3%6.7%
September11%12%9.2%5.2%
October1.2%0.2%0.1%0.1%
November0%0%0%0%
December0%0%0%0%

Neighboring states

  • Ohio: arrives mid August, 1 week later than Michigan
  • Indiana: arrives mid August, 1 week later than Michigan
  • Illinois: arrives mid August, 1 week later than Michigan
  • Wisconsin: arrives mid August, 1 week later than Michigan

Common questions

When do Bay-breasted Warblers arrive in Michigan?
Bay-breasted Warblers mostly pass through Michigan: they arrive in the second week of August, peak in the second week of September (11% of checklists), and most are gone by early October.
When do Bay-breasted Warblers leave Michigan?
Most Bay-breasted Warblers have left Michigan by early October, when reports fall below half their usual rate.
When is the best time to see a Bay-breasted Warbler in Michigan?
The Bay-breasted Warbler is reported most often in the second week of September, on about 11% of Michigan checklists.
Where in Michigan are Bay-breasted Warblers seen most often?
By county, Ogemaw County, Washtenaw County, and Livingston County have the highest peak reporting rates for the Bay-breasted Warbler (counties with at least 200 checklists).