WhenToBird

Cardellina pusilla · Parulidae

When Do Wilson's Warblers Arrive in Maine?

Adult male Wilson's Warbler
Photo: Donald Hampton, CC BY-SA 4.0 via iNaturalist

Wilson's Warblers mostly pass through Maine: they arrive in early May, peak in mid May (5.4% of checklists), and most are gone by early June.

When to look

First arrivalsMay 1-7early May
Common byMay 1-7early May
PeakMay 15-21mid May
Most gone byJun 1-7early June

Best: mid May. First arrivals early May; most are gone by early June. Peak: on about 5.4% of Maine checklists.

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

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

0%5%10%Jan 1-7: 0.1% of 15499 checklistsJan 8-14: 0.1% of 11141 checklistsJan 15-21: 0.1% of 10729 checklistsJan 22-31: 0% of 15084 checklistsFeb 1-7: 0% of 9403 checklistsFeb 8-14: 0% of 11268 checklistsFeb 15-21: 0% of 14061 checklistsFeb 22-28: 0% of 9977 checklistsMar 1-7: 0% of 9649 checklistsMar 8-14: 0% of 11781 checklistsMar 15-21: 0% of 11613 checklistsMar 22-31: 0% of 17798 checklistsApr 1-7: 0% of 14638 checklistsApr 8-14: 0.1% of 16511 checklistsApr 15-21: 0.1% of 17164 checklistsApr 22-30: 0.1% of 22602 checklistsMay 1-7: 0.3% of 22556 checklistsMay 8-14: 4.4% of 27842 checklistsMay 15-21: 9.0% of 27748 checklistsMay 22-31: 3.5% of 38715 checklistsJun 1-7: 0.3% of 26916 checklistsJun 8-14: 0.2% of 23737 checklistsJun 15-21: 0.2% of 22733 checklistsJun 22-30: 0.2% of 28248 checklistsJul 1-7: 0.1% of 20290 checklistsJul 8-14: 0.1% of 18534 checklistsJul 15-21: 0.1% of 17319 checklistsJul 22-31: 0.1% of 22815 checklistsAug 1-7: 0.1% of 15004 checklistsAug 8-14: 0.1% of 14603 checklistsAug 15-21: 0.4% of 14972 checklistsAug 22-31: 0.8% of 19813 checklistsSep 1-7: 1.4% of 14567 checklistsSep 8-14: 2.0% of 14520 checklistsSep 15-21: 1.9% of 14339 checklistsSep 22-30: 1.4% of 16879 checklistsOct 1-7: 0.5% of 12959 checklistsOct 8-14: 0.2% of 13168 checklistsOct 15-21: 0.1% of 11184 checklistsOct 22-31: 0.1% of 13717 checklistsNov 1-7: 0% of 9823 checklistsNov 8-14: 0% of 9007 checklistsNov 15-21: 0.1% of 8528 checklistsNov 22-30: 0.1% of 10228 checklistsDec 1-7: 0.1% of 7505 checklistsDec 8-14: 0% of 7982 checklistsDec 15-21: 0.1% of 10455 checklistsDec 22-31: 0.1% of 14285 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 Maine 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 Maine

Best counties

Share of checklists at the peak
  1. Cumberland CountyBest mid May · 7127 checklists that week, 169,501 in all9.4%
  2. Waldo CountyBest mid May · 1075 checklists that week, 33,433 in all8.9%
  3. York CountyBest mid May · 3746 checklists that week, 101,844 in all7.7%
  4. Lincoln CountyBest mid May · 2206 checklists that week, 59,429 in all6.8%
  5. Kennebec CountyBest mid May · 1704 checklists that week, 48,185 in all4.7%
  6. Androscoggin CountyBest mid May · 675 checklists that week, 16,955 in all3.9%

Best spots

Share of checklists at the peak
  1. Timber PointYork County, best late May · 260 checklists that week, 3,561 in all40%
  2. Long CoveWaldo County, best mid May · 167 checklists that week, 2,744 in all39%
  3. Cobbosseecontee Stream ReservoirKennebec County, best late May · 53 checklists that week, 297 in all38%
  4. Capisic Pond ParkCumberland County, best mid May · 604 checklists that week, 4,578 in all37%
  5. Great Pond (Halftide Rock)York County, best late May · 30 checklists that week, 291 in all29%
  6. Fort Foster ParkYork County, best late May · 95 checklists that week, 2,318 in all28%

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

Best time of day

In Maine, the Wilson's Warbler is most often listed on checklists started between 5 and 7 am (2.7% of those checklists).

0%1%2%3%12 am: too few checklists (510) to judge1 am: too few checklists (517) to judge2 am: too few checklists (581) to judge3 am: too few checklists (3242) to judge4 am: too few checklists (7221) to judge5 am: 2.8% of 19895 checklists6 am: 2.6% of 54578 checklists7 am: 1.4% of 92775 checklists8 am: 1.0% of 86962 checklists9 am: 0.8% of 78989 checklists10 am: 0.7% of 70954 checklists11 am: 0.5% of 59331 checklists12 pm: 0.5% of 50943 checklists1 pm: 0.4% of 49775 checklists2 pm: 0.4% of 49001 checklists3 pm: 0.4% of 43252 checklists4 pm: 0.5% of 33413 checklists5 pm: 0.6% of 25547 checklists6 pm: 0.5% of 18309 checklists7 pm: too few checklists (14287) to judge8 pm: too few checklists (5336) to judge9 pm: too few checklists (2253) to judge10 pm: too few checklists (1518) to judge11 pm: too few checklists (720) 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
January0.1%0.1%0.1%0%
February0%0%0%0%
March0%0%0%0%
April0%0.1%0.1%0.1%
May0.3%4.4%9.0%3.5%
June0.3%0.2%0.2%0.2%
July0.1%0.1%0.1%0.1%
August0.1%0.1%0.4%0.8%
September1.4%2.0%1.9%1.4%
October0.5%0.2%0.1%0.1%
November0%0%0.1%0.1%
December0.1%0%0.1%0.1%

Neighboring states

  • New Hampshire: arrives early May, in the same week than Maine
  • Massachusetts: arrives early May, in the same week than Maine
  • Vermont: arrives mid August, 14 weeks later than Maine
  • Rhode Island: arrives early May, in the same week than Maine

Common questions

When do Wilson's Warblers arrive in Maine?
Wilson's Warblers mostly pass through Maine: they arrive in early May, peak in mid May (5.4% of checklists), and most are gone by early June.
When do Wilson's Warblers leave Maine?
Most Wilson's Warblers have left Maine by early June, when reports fall below half their usual rate.
When is the best time to see a Wilson's Warbler in Maine?
The Wilson's Warbler is reported most often in mid May, on about 5.4% of Maine checklists.
Where in Maine are Wilson's Warblers seen most often?
By county, Cumberland County, Waldo County, and York County have the highest peak reporting rates for the Wilson's Warbler (counties with at least 200 checklists).