WhenToBird

Setophaga pensylvanica · Parulidae

When Do Chestnut-sided Warblers Arrive in Minnesota?

Adult male Chestnut-sided Warbler
Photo: Matt Felperin, CC BY 4.0 via iNaturalist

Chestnut-sided Warblers arrive in Minnesota in early May, peak in late May (14% of checklists), and most are gone by mid September.

When to look

First arrivalsMay 1-7early May
Common byMay 1-7early May
PeakMay 22-31late May
Most gone bySep 15-21mid September

Best: late May. First arrivals early May; most are gone by mid September. Peak: on about 14% of Minnesota checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Marnot usually seen
  4. Aprnot usually seen
  5. Maypeak season
  6. Junpeak season
  7. Julcommon
  8. Augcommon
  9. Seppeak season
  10. Octrare
  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 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: 0.1% of 43574 checklistsMay 1-7: 0.7% of 39300 checklistsMay 8-14: 11% of 45927 checklistsMay 15-21: 18% of 36632 checklistsMay 22-31: 14% of 43809 checklistsJun 1-7: 8.5% of 23418 checklistsJun 8-14: 8.0% of 20450 checklistsJun 15-21: 8.2% of 19470 checklistsJun 22-30: 7.4% of 23418 checklistsJul 1-7: 6.2% of 19104 checklistsJul 8-14: 4.2% of 16927 checklistsJul 15-21: 2.6% of 15635 checklistsJul 22-31: 2.2% of 22073 checklistsAug 1-7: 2.5% of 16255 checklistsAug 8-14: 3.3% of 16840 checklistsAug 15-21: 7.4% of 17475 checklistsAug 22-31: 12% of 26545 checklistsSep 1-7: 12% of 20750 checklistsSep 8-14: 9.7% of 18494 checklistsSep 15-21: 4.3% of 18215 checklistsSep 22-30: 1.7% of 24463 checklistsOct 1-7: 0.1% of 18252 checklistsOct 8-14: 0.1% of 19527 checklistsOct 15-21: 0.1% of 17098 checklistsOct 22-31: 0% 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. Clearwater CountyBest the second week of June · 64 checklists that week, 2,315 in all52%
  2. Lake CountyBest early June · 511 checklists that week, 19,908 in all41%
  3. Steele CountyBest early September · 121 checklists that week, 4,784 in all36%
  4. Hubbard CountyBest late May · 342 checklists that week, 5,131 in all36%
  5. Cook CountyBest early June · 533 checklists that week, 14,913 in all36%
  6. Lake of the Woods CountyBest mid June · 90 checklists that week, 1,280 in all35%

Best spots

Share of checklists at the peak
  1. Hawk RidgeSt. Louis County, best early June · 32 checklists that week, 2,979 in all88%
  2. Oberg LakeCook County, best late June · 26 checklists that week, 275 in all84%
  3. Tamarack LakeClearwater County, best early June · 20 checklists that week, 313 in all82%
  4. North Arm Lake ItascaClearwater County, best early June · 27 checklists that week, 340 in all76%
  5. Tamarac National Wildlife Refuge (Chippewa Lake)Becker County, best mid May · 40 checklists that week, 175 in all75%
  6. Centerville LakeAnoka County, best late August · 70 checklists that week, 628 in all71%

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

Best time of day

In Minnesota, the Chestnut-sided Warbler is most often listed on checklists started between 6 and 8 am (7.2% of those checklists).

0%5%10%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: 9.7% of 35775 checklists7 am: 6.3% of 90565 checklists8 am: 5.0% of 110612 checklists9 am: 4.2% of 106128 checklists10 am: 3.6% of 96131 checklists11 am: 3.1% of 83750 checklists12 pm: 2.7% of 76254 checklists1 pm: 2.7% of 73480 checklists2 pm: 2.5% of 73703 checklists3 pm: 2.3% of 75249 checklists4 pm: 2.7% of 68810 checklists5 pm: 2.7% of 51899 checklists6 pm: 3.1% of 38524 checklists7 pm: 2.4% 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%0.1%
May0.7%11%18%14%
June8.5%8.0%8.2%7.4%
July6.2%4.2%2.6%2.2%
August2.5%3.3%7.4%12%
September12%9.7%4.3%1.7%
October0.1%0.1%0.1%0%
November0%0%0%0%
December0%0%0%0%

Neighboring states

  • Iowa: arrives the second week of August, 13 weeks later than Minnesota
  • Wisconsin: arrives early May, in the same week than Minnesota
  • South Dakota: arrives early May, in the same week than Minnesota
  • North Dakota: arrives the second week of May, 1 week later than Minnesota

Common questions

When do Chestnut-sided Warblers arrive in Minnesota?
Chestnut-sided Warblers arrive in Minnesota in early May, peak in late May (14% of checklists), and most are gone by mid September.
When do Chestnut-sided Warblers leave Minnesota?
Most Chestnut-sided Warblers have left Minnesota by mid September, when reports fall below half their usual rate. Stragglers are still reported until late September.
When is the best time to see a Chestnut-sided Warbler in Minnesota?
The Chestnut-sided Warbler is reported most often in late May, on about 14% of Minnesota checklists.
Where in Minnesota are Chestnut-sided Warblers seen most often?
By county, Clearwater County, Lake County, and Steele County have the highest peak reporting rates for the Chestnut-sided Warbler (counties with at least 200 checklists).