WhenToBird

Setophaga caerulescens · Parulidae

When Do Black-throated Blue Warblers Arrive in New Hampshire?

Adult male Black-throated Blue Warbler
Photo: Dan Vickers, CC BY 4.0 via iNaturalist

Black-throated Blue Warblers reach New Hampshire in late April, are common by early May, peak in mid May (13% of checklists), and most are gone by mid July.

When to look

First arrivalsApr 22-30late April
Common byMay 1-7early May
PeakMay 15-21mid May
Most gone byJul 15-21mid July

Best: mid May. First arrivals late April; most are gone by mid July. Peak: on about 13% of New Hampshire checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Marnot usually seen
  4. Apruncommon
  5. Maypeak season
  6. Junpeak season
  7. Julpeak season
  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%15%20%Jan 1-7: 0% of 8253 checklistsJan 8-14: 0% of 5998 checklistsJan 15-21: 0.1% of 5734 checklistsJan 22-31: 0.1% of 7776 checklistsFeb 1-7: 0% of 5253 checklistsFeb 8-14: 0.1% of 6802 checklistsFeb 15-21: 0% of 8852 checklistsFeb 22-28: 0% of 5792 checklistsMar 1-7: 0% of 6187 checklistsMar 8-14: 0% of 6977 checklistsMar 15-21: 0% of 7863 checklistsMar 22-31: 0% of 11746 checklistsApr 1-7: 0% of 9329 checklistsApr 8-14: 0% of 10499 checklistsApr 15-21: 0% of 10376 checklistsApr 22-30: 0.4% of 13086 checklistsMay 1-7: 5.9% of 13198 checklistsMay 8-14: 13% of 14980 checklistsMay 15-21: 15% of 12487 checklistsMay 22-31: 12% of 14294 checklistsJun 1-7: 11% of 8974 checklistsJun 8-14: 11% of 8395 checklistsJun 15-21: 12% of 7670 checklistsJun 22-30: 11% of 9188 checklistsJul 1-7: 11% of 7707 checklistsJul 8-14: 8.6% of 6554 checklistsJul 15-21: 7.4% of 6636 checklistsJul 22-31: 4.7% of 9599 checklistsAug 1-7: 3.0% of 6436 checklistsAug 8-14: 2.6% of 6477 checklistsAug 15-21: 2.1% of 6510 checklistsAug 22-31: 2.6% of 9762 checklistsSep 1-7: 3.0% of 6700 checklistsSep 8-14: 4.0% of 6012 checklistsSep 15-21: 3.0% of 6238 checklistsSep 22-30: 2.8% of 7619 checklistsOct 1-7: 1.4% of 6702 checklistsOct 8-14: 0.9% of 6863 checklistsOct 15-21: 0.3% of 6284 checklistsOct 22-31: 0.1% of 8287 checklistsNov 1-7: 0% of 7584 checklistsNov 8-14: 0.1% of 6056 checklistsNov 15-21: 0.1% of 5597 checklistsNov 22-30: 0.1% of 7140 checklistsDec 1-7: 0.1% of 4623 checklistsDec 8-14: 0.1% of 4920 checklistsDec 15-21: 0.1% of 6416 checklistsDec 22-31: 0% of 7659 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 New Hampshire 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 New Hampshire

Best counties

Share of checklists at the peak
  1. Coos CountyBest late May · 1371 checklists that week, 27,719 in all26%
  2. Sullivan CountyBest late June · 373 checklists that week, 13,105 in all25%
  3. Carroll CountyBest mid May · 1139 checklists that week, 30,580 in all22%
  4. Grafton CountyBest mid June · 1198 checklists that week, 45,699 in all20%
  5. Belknap CountyBest mid May · 411 checklists that week, 13,295 in all17%
  6. Cheshire CountyBest mid May · 1135 checklists that week, 39,834 in all16%

Best spots

Share of checklists at the peak
  1. Hubbard Brook Experimental ForestGrafton County, best early July · 25 checklists that week, 444 in all93%
  2. Deception BrookCoos County, best late May · 22 checklists that week, 138 in all86%
  3. Silvio O. Conte National Fish and Wildlife RefugeCoos County, best late May · 68 checklists that week, 786 in all86%
  4. Little Cherry PondCoos County, best late May · 27 checklists that week, 287 in all75%
  5. Cherry PondCoos County, best late May · 24 checklists that week, 414 in all68%
  6. Wantastiquet Mountain Natural AreaCheshire County, best mid May · 23 checklists that week, 419 in all68%

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

Best time of day

In New Hampshire, the Black-throated Blue Warbler is most often listed on checklists started between 6 and 8 am (6.2% of those checklists).

0%2%4%6%8%12 am: too few checklists (219) to judge1 am: too few checklists (192) to judge2 am: too few checklists (176) to judge3 am: too few checklists (234) to judge4 am: too few checklists (1042) to judge5 am: too few checklists (6352) to judge6 am: 7.8% of 23140 checklists7 am: 5.3% of 43401 checklists8 am: 4.5% of 48039 checklists9 am: 3.8% of 43328 checklists10 am: 3.4% of 37073 checklists11 am: 2.9% of 32028 checklists12 pm: 2.4% of 27396 checklists1 pm: 2.2% of 25182 checklists2 pm: 2.0% of 24318 checklists3 pm: 2.1% of 21974 checklists4 pm: 2.1% of 17958 checklists5 pm: 2.1% of 14528 checklists6 pm: 2.4% of 9144 checklists7 pm: too few checklists (5341) to judge8 pm: too few checklists (1845) to judge9 pm: too few checklists (578) to judge10 pm: too few checklists (346) to judge11 pm: too few checklists (256) 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%0.1%0.1%
February0%0.1%0%0%
March0%0%0%0%
April0%0%0%0.4%
May5.9%13%15%12%
June11%11%12%11%
July11%8.6%7.4%4.7%
August3.0%2.6%2.1%2.6%
September3.0%4.0%3.0%2.8%
October1.4%0.9%0.3%0.1%
November0%0.1%0.1%0.1%
December0.1%0.1%0.1%0%

Neighboring states

  • Massachusetts: arrives late April, in the same week than New Hampshire
  • Vermont: arrives late April, in the same week than New Hampshire
  • Rhode Island: arrives late April, in the same week than New Hampshire
  • Maine: arrives late April, in the same week than New Hampshire

Common questions

When do Black-throated Blue Warblers arrive in New Hampshire?
Black-throated Blue Warblers reach New Hampshire in late April, are common by early May, peak in mid May (13% of checklists), and most are gone by mid July.
When do Black-throated Blue Warblers leave New Hampshire?
Most Black-throated Blue Warblers have left New Hampshire by mid July, when reports fall below half their usual rate. Stragglers are still reported until early October.
When is the best time to see a Black-throated Blue Warbler in New Hampshire?
The Black-throated Blue Warbler is reported most often in mid May, on about 13% of New Hampshire checklists.
Where in New Hampshire are Black-throated Blue Warblers seen most often?
By county, Coos County, Sullivan County, and Carroll County have the highest peak reporting rates for the Black-throated Blue Warbler (counties with at least 200 checklists).