WhenToBird

Tachycineta bicolor · Hirundinidae

When Do Tree Swallows Arrive in New Jersey?

Adult Tree Swallow
Photo: Carter Dorscht, CC0 1.0 via iNaturalist

Tree Swallows reach New Jersey in early March, are common by mid March, peak in early June (32% of checklists), and most are gone by late October.

When to look

First arrivalsMar 1-7early March
Common byMar 15-21mid March
PeakJun 1-7early June
Most gone byOct 22-31late October

Best: early June. First arrivals early March; most are gone by late October. Peak: on about 32% of New Jersey checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Marcommon
  4. Aprpeak season
  5. Maypeak season
  6. Junpeak season
  7. Julpeak season
  8. Augcommon
  9. Sepcommon
  10. Octcommon
  11. Novuncommon
  12. Decrare

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

0%10%20%30%40%Jan 1-7: 0.5% of 28167 checklistsJan 8-14: 0.4% of 20583 checklistsJan 15-21: 0.3% of 19739 checklistsJan 22-31: 0.3% of 24586 checklistsFeb 1-7: 0.2% of 17226 checklistsFeb 8-14: 0.4% of 19567 checklistsFeb 15-21: 0.3% of 26553 checklistsFeb 22-28: 0.7% of 19046 checklistsMar 1-7: 1.9% of 17969 checklistsMar 8-14: 5.4% of 18976 checklistsMar 15-21: 9.8% of 18581 checklistsMar 22-31: 18% of 27590 checklistsApr 1-7: 24% of 21202 checklistsApr 8-14: 29% of 23609 checklistsApr 15-21: 30% of 25056 checklistsApr 22-30: 32% of 36679 checklistsMay 1-7: 31% of 38378 checklistsMay 8-14: 30% of 44071 checklistsMay 15-21: 32% of 34076 checklistsMay 22-31: 32% of 32558 checklistsJun 1-7: 31% of 18049 checklistsJun 8-14: 32% of 15597 checklistsJun 15-21: 30% of 14894 checklistsJun 22-30: 28% of 17187 checklistsJul 1-7: 23% of 13406 checklistsJul 8-14: 22% of 12550 checklistsJul 15-21: 21% of 12358 checklistsJul 22-31: 22% of 18382 checklistsAug 1-7: 22% of 13689 checklistsAug 8-14: 21% of 14006 checklistsAug 15-21: 22% of 14483 checklistsAug 22-31: 21% of 23182 checklistsSep 1-7: 17% of 17984 checklistsSep 8-14: 16% of 18320 checklistsSep 15-21: 12% of 20491 checklistsSep 22-30: 15% of 26176 checklistsOct 1-7: 18% of 24112 checklistsOct 8-14: 19% of 24603 checklistsOct 15-21: 22% of 24549 checklistsOct 22-31: 15% of 26206 checklistsNov 1-7: 7.4% of 17469 checklistsNov 8-14: 4.9% of 15102 checklistsNov 15-21: 4.1% of 14958 checklistsNov 22-30: 2.9% of 19447 checklistsDec 1-7: 1.9% of 14017 checklistsDec 8-14: 1.3% of 14625 checklistsDec 15-21: 1.2% of 16937 checklistsDec 22-31: 0.6% 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. Bergen CountyBest early June · 1328 checklists that week, 73,457 in all46%
  2. Salem CountyBest the second week of July · 105 checklists that week, 9,658 in all45%
  3. Warren CountyBest mid April · 433 checklists that week, 20,077 in all43%
  4. Mercer CountyBest the second week of May · 2095 checklists that week, 56,614 in all43%
  5. Burlington CountyBest the second week of May · 1835 checklists that week, 52,358 in all43%
  6. Somerset CountyBest late May · 1998 checklists that week, 58,057 in all42%

Best spots

Share of checklists at the peak
  1. Hoffman ParkHunterdon County, best early June · 25 checklists that week, 512 in all97%
  2. Mill Creek MarshHudson County, best mid April · 29 checklists that week, 1,764 in all97%
  3. Richard W de Korte ParkBergen County, best late April · 298 checklists that week, 10,095 in all96%
  4. South Branch River ReserveHunterdon County, best early June · 77 checklists that week, 3,829 in all96%

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

Best time of day

In New Jersey, the Tree Swallow is most often listed on checklists started between 6 and 8 am (21% of those checklists).

0%10%20%30%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: 24% of 50447 checklists7 am: 19% of 118312 checklists8 am: 18% of 123273 checklists9 am: 18% of 107783 checklists10 am: 17% of 97537 checklists11 am: 15% of 82427 checklists12 pm: 14% of 72581 checklists1 pm: 13% of 71478 checklists2 pm: 13% of 69994 checklists3 pm: 12% of 66822 checklists4 pm: 13% of 55950 checklists5 pm: 16% of 41360 checklists6 pm: 18% 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
January0.5%0.4%0.3%0.3%
February0.2%0.4%0.3%0.7%
March1.9%5.4%9.8%18%
April24%29%30%32%
May31%30%32%32%
June31%32%30%28%
July23%22%21%22%
August22%21%22%21%
September17%16%12%15%
October18%19%22%15%
November7.4%4.9%4.1%2.9%
December1.9%1.3%1.2%0.6%

Neighboring states

  • Delaware: arrives early March, in the same week than New Jersey
  • Connecticut: arrives mid March, 2 weeks later than New Jersey
  • Pennsylvania: arrives the second week of March, 1 week later than New Jersey
  • New York: arrives mid March, 2 weeks later than New Jersey

Common questions

When do Tree Swallows arrive in New Jersey?
Tree Swallows reach New Jersey in early March, are common by mid March, peak in early June (32% of checklists), and most are gone by late October.
When do Tree Swallows leave New Jersey?
Most Tree Swallows have left New Jersey by late October, when reports fall below half their usual rate. Stragglers are still reported until late November.
When is the best time to see a Tree Swallow in New Jersey?
The Tree Swallow is reported most often in early June, on about 32% of New Jersey checklists.
Where in New Jersey are Tree Swallows seen most often?
By county, Bergen County, Salem County, and Warren County have the highest peak reporting rates for the Tree Swallow (counties with at least 200 checklists).