WhenToBird

Setophaga castanea · Parulidae

When Do Bay-breasted Warblers Arrive in Minnesota?

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

Bay-breasted Warblers mostly pass through Minnesota: they arrive in mid August, peak in early September (4.8% of checklists), and most are gone by early October.

When to look

First arrivalsAug 15-21mid August
Common byAug 15-21mid August
PeakSep 1-7early September
Most gone byOct 1-7early October

Best: early September. First arrivals mid August; most are gone by early October. Peak: on about 4.8% of Minnesota checklists.

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

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

0%2%4%6%Jan 1-7: 0% of 20628 checklistsJan 8-14: 0% of 14594 checklistsJan 15-21: 0% of 14238 checklistsJan 22-31: 0% of 20725 checklistsFeb 1-7: 0% of 14484 checklistsFeb 8-14: 0% of 15988 checklistsFeb 15-21: 0% of 20718 checklistsFeb 22-28: 0% of 15754 checklistsMar 1-7: 0% of 16125 checklistsMar 8-14: 0% of 19035 checklistsMar 15-21: 0% of 19586 checklistsMar 22-31: 0% of 30192 checklistsApr 1-7: 0% of 24262 checklistsApr 8-14: 0% of 30223 checklistsApr 15-21: 0% of 29085 checklistsApr 22-30: 0% of 43574 checklistsMay 1-7: 0.1% of 39300 checklistsMay 8-14: 1.6% of 45927 checklistsMay 15-21: 3.9% of 36632 checklistsMay 22-31: 1.8% of 43809 checklistsJun 1-7: 0.2% of 23418 checklistsJun 8-14: 0.2% of 20450 checklistsJun 15-21: 0.1% of 19470 checklistsJun 22-30: 0.1% of 23418 checklistsJul 1-7: 0.1% of 19104 checklistsJul 8-14: 0.1% of 16927 checklistsJul 15-21: 0.1% of 15635 checklistsJul 22-31: 0.1% of 22073 checklistsAug 1-7: 0.1% of 16255 checklistsAug 8-14: 0.2% of 16840 checklistsAug 15-21: 1.1% of 17475 checklistsAug 22-31: 3.7% of 26545 checklistsSep 1-7: 5.9% of 20750 checklistsSep 8-14: 5.2% of 18494 checklistsSep 15-21: 3.0% of 18215 checklistsSep 22-30: 1.2% of 24463 checklistsOct 1-7: 0.3% of 18252 checklistsOct 8-14: 0.1% of 19527 checklistsOct 15-21: 0.1% of 17098 checklistsOct 22-31: 0.1% of 24570 checklistsNov 1-7: 0% of 16744 checklistsNov 8-14: 0% of 13483 checklistsNov 15-21: 0% of 12525 checklistsNov 22-30: 0% of 17023 checklistsDec 1-7: 0% of 11645 checklistsDec 8-14: 0% of 11567 checklistsDec 15-21: 0% of 13343 checklistsDec 22-31: 0% of 19759 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 Minnesota 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 Minnesota

Best counties

Share of checklists at the peak
  1. Redwood CountyBest early September · 23 checklists that week, 1,193 in all20%
  2. Kanabec CountyBest the second week of September · 13 checklists that week, 1,155 in all20%
  3. Fillmore CountyBest the second week of September · 96 checklists that week, 3,791 in all19%
  4. Swift CountyBest early September · 28 checklists that week, 1,275 in all16%
  5. Chippewa CountyBest early September · 34 checklists that week, 1,298 in all15%
  6. Mille Lacs CountyBest early September · 38 checklists that week, 1,955 in all14%

Best spots

Share of checklists at the peak
  1. Centerville LakeAnoka County, best early September · 71 checklists that week, 628 in all54%
  2. Shakopee LakeChippewa County, best late August · 25 checklists that week, 129 in all42%
  3. Shakopee Wayside ParkScott County, best late August · 20 checklists that week, 1,639 in all33%
  4. Gables LakeWashington County, best the second week of September · 33 checklists that week, 1,181 in all27%
  5. Sucker Lake Regional ParkRamsey County, best the second week of September · 166 checklists that week, 4,040 in all26%
  6. Frontenac State ParkGoodhue County, best early September · 20 checklists that week, 845 in all25%

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

Best time of day

In Minnesota, the Bay-breasted Warbler 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 (349) to judge1 am: too few checklists (331) to judge2 am: too few checklists (286) to judge3 am: too few checklists (364) to judge4 am: too few checklists (863) to judge5 am: too few checklists (7598) to judge6 am: 1.5% of 35775 checklists7 am: 1.3% of 90565 checklists8 am: 1.0% of 110612 checklists9 am: 0.8% of 106128 checklists10 am: 0.7% of 96131 checklists11 am: 0.6% of 83750 checklists12 pm: 0.5% of 76254 checklists1 pm: 0.5% of 73480 checklists2 pm: 0.5% of 73703 checklists3 pm: 0.5% of 75249 checklists4 pm: 0.6% of 68810 checklists5 pm: 0.7% of 51899 checklists6 pm: 0.6% of 38524 checklists7 pm: 0.3% of 25120 checklists8 pm: too few checklists (10568) to judge9 pm: too few checklists (2420) to judge10 pm: too few checklists (748) to judge11 pm: too few checklists (420) 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%
May0.1%1.6%3.9%1.8%
June0.2%0.2%0.1%0.1%
July0.1%0.1%0.1%0.1%
August0.1%0.2%1.1%3.7%
September5.9%5.2%3.0%1.2%
October0.3%0.1%0.1%0.1%
November0%0%0%0%
December0%0%0%0%

Neighboring states

  • Iowa: arrives mid August, in the same week than Minnesota
  • Wisconsin: arrives mid August, in the same week than Minnesota
  • North Dakota: arrives late August, 1 week later than Minnesota
  • Nebraska: arrives late August, 1 week later than Minnesota

Common questions

When do Bay-breasted Warblers arrive in Minnesota?
Bay-breasted Warblers mostly pass through Minnesota: they arrive in mid August, peak in early September (4.8% of checklists), and most are gone by early October.
When do Bay-breasted Warblers leave Minnesota?
Most Bay-breasted Warblers have left Minnesota by early October, when reports fall below half their usual rate.
When is the best time to see a Bay-breasted Warbler in Minnesota?
The Bay-breasted Warbler is reported most often in early September, on about 4.8% of Minnesota checklists.
Where in Minnesota are Bay-breasted Warblers seen most often?
By county, Redwood County, Kanabec County, and Fillmore County have the highest peak reporting rates for the Bay-breasted Warbler (counties with at least 200 checklists).