WhenToBird

Setophaga caerulescens · Parulidae

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

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

Black-throated Blue Warblers arrive in New Jersey in mid April, peak in the second week of May (10% of checklists), and most are gone by mid July.

When to look

First arrivalsApr 15-21mid April
Common byApr 15-21mid April
PeakMay 8-14the second week of May
Most gone byJul 15-21mid July

Best: the second week of May. First arrivals mid April; most are gone by mid July. Peak: on about 10% of New Jersey checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Marnot usually seen
  4. Aprcommon
  5. Maypeak season
  6. Junrare
  7. Julnot usually seen
  8. Auguncommon
  9. Sepcommon
  10. Octcommon
  11. Novnot usually seen
  12. Decnot usually seen

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

0%5%10%15%Jan 1-7: 0.1% of 28167 checklistsJan 8-14: 0.1% of 20583 checklistsJan 15-21: 0.1% of 19739 checklistsJan 22-31: 0.1% of 24586 checklistsFeb 1-7: 0.1% of 17226 checklistsFeb 8-14: 0.1% of 19567 checklistsFeb 15-21: 0.1% of 26553 checklistsFeb 22-28: 0.1% of 19046 checklistsMar 1-7: 0.1% of 17969 checklistsMar 8-14: 0.1% of 18976 checklistsMar 15-21: 0.1% of 18581 checklistsMar 22-31: 0.1% of 27590 checklistsApr 1-7: 0.1% of 21202 checklistsApr 8-14: 0.1% of 23609 checklistsApr 15-21: 0.1% of 25056 checklistsApr 22-30: 1.9% of 36679 checklistsMay 1-7: 12% of 38378 checklistsMay 8-14: 12% of 44071 checklistsMay 15-21: 6.5% of 34076 checklistsMay 22-31: 1.0% of 32558 checklistsJun 1-7: 0.3% of 18049 checklistsJun 8-14: 0.2% of 15597 checklistsJun 15-21: 0.1% of 14894 checklistsJun 22-30: 0.1% of 17187 checklistsJul 1-7: 0.1% of 13406 checklistsJul 8-14: 0.1% of 12550 checklistsJul 15-21: 0% of 12358 checklistsJul 22-31: 0.1% of 18382 checklistsAug 1-7: 0% of 13689 checklistsAug 8-14: 0.1% of 14006 checklistsAug 15-21: 0.1% of 14483 checklistsAug 22-31: 1.5% of 23182 checklistsSep 1-7: 3.1% of 17984 checklistsSep 8-14: 4.9% of 18320 checklistsSep 15-21: 6.1% of 20491 checklistsSep 22-30: 7.2% of 26176 checklistsOct 1-7: 7.6% of 24112 checklistsOct 8-14: 6.8% of 24603 checklistsOct 15-21: 2.8% of 24549 checklistsOct 22-31: 0.7% of 26206 checklistsNov 1-7: 0.1% of 17469 checklistsNov 8-14: 0.1% of 15102 checklistsNov 15-21: 0.1% of 14958 checklistsNov 22-30: 0.1% of 19447 checklistsDec 1-7: 0.1% of 14017 checklistsDec 8-14: 0.1% of 14625 checklistsDec 15-21: 0.1% of 16937 checklistsDec 22-31: 0.1% of 26651 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 Jersey 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 Jersey

Best counties

Share of checklists at the peak
  1. Passaic CountyBest the second week of May · 1413 checklists that week, 24,933 in all36%
  2. Essex CountyBest the second week of May · 1083 checklists that week, 28,396 in all19%
  3. Union CountyBest the second week of May · 872 checklists that week, 23,647 in all19%
  4. Mercer CountyBest the second week of May · 2095 checklists that week, 56,614 in all17%
  5. Hudson CountyBest the second week of May · 776 checklists that week, 21,191 in all16%
  6. Burlington CountyBest late September · 1085 checklists that week, 52,358 in all15%

Best spots

Share of checklists at the peak
  1. South Mountain Reservation (Maplewood)Essex County, best the second week of May · 47 checklists that week, 306 in all65%
  2. Garret Mountain ReservationPassaic County, best the second week of May · 622 checklists that week, 5,614 in all62%
  3. Voorhees State ParkHunterdon County, best the second week of May · 77 checklists that week, 362 in all56%
  4. Comeys LakeGloucester County, best the second week of May · 21 checklists that week, 373 in all54%
  5. Losen Slote ParkBergen County, best the second week of May · 83 checklists that week, 1,252 in all53%
  6. Borgs Woods Nature PreserveBergen County, best the second week of May · 30 checklists that week, 272 in all53%

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

Best time of day

In New Jersey, the Black-throated Blue Warbler is most often listed on checklists started between 6 and 8 am (5.0% of those checklists).

0%2%4%6%8%12 am: too few checklists (746) to judge1 am: too few checklists (640) to judge2 am: too few checklists (606) to judge3 am: too few checklists (755) to judge4 am: too few checklists (1681) to judge5 am: too few checklists (11258) to judge6 am: 7.3% of 50447 checklists7 am: 4.0% of 118312 checklists8 am: 2.8% of 123273 checklists9 am: 2.2% of 107783 checklists10 am: 1.7% of 97537 checklists11 am: 1.4% of 82427 checklists12 pm: 1.4% of 72581 checklists1 pm: 1.1% of 71478 checklists2 pm: 1.1% of 69994 checklists3 pm: 1.2% of 66822 checklists4 pm: 1.2% of 55950 checklists5 pm: 1.2% of 41360 checklists6 pm: 0.7% of 28122 checklists7 pm: too few checklists (14727) to judge8 pm: too few checklists (4257) to judge9 pm: too few checklists (1273) to judge10 pm: too few checklists (920) to judge11 pm: too few checklists (693) 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%0.1%
February0.1%0.1%0.1%0.1%
March0.1%0.1%0.1%0.1%
April0.1%0.1%0.1%1.9%
May12%12%6.5%1.0%
June0.3%0.2%0.1%0.1%
July0.1%0.1%0%0.1%
August0%0.1%0.1%1.5%
September3.1%4.9%6.1%7.2%
October7.6%6.8%2.8%0.7%
November0.1%0.1%0.1%0.1%
December0.1%0.1%0.1%0.1%

Neighboring states

  • Delaware: arrives late April, 1 week later than New Jersey
  • Connecticut: arrives late April, 1 week later than New Jersey
  • Pennsylvania: arrives late April, 1 week later than New Jersey
  • New York: arrives late April, 1 week later than New Jersey

Common questions

When do Black-throated Blue Warblers arrive in New Jersey?
Black-throated Blue Warblers arrive in New Jersey in mid April, peak in the second week of May (10% of checklists), and most are gone by mid July.
When do Black-throated Blue Warblers leave New Jersey?
Most Black-throated Blue Warblers have left New Jersey by mid July, when reports fall below half their usual rate.
When is the best time to see a Black-throated Blue Warbler in New Jersey?
The Black-throated Blue Warbler is reported most often in the second week of May, on about 10% of New Jersey checklists.
Where in New Jersey are Black-throated Blue Warblers seen most often?
By county, Passaic County, Essex County, and Union County have the highest peak reporting rates for the Black-throated Blue Warbler (counties with at least 200 checklists).