WhenToBird

Spizelloides arborea · Passerellidae

When Do American Tree Sparrows Arrive in New Jersey?

Adult American Tree Sparrow
Photo: Michael, CC BY 4.0 via iNaturalist

American Tree Sparrows are winter birds in New Jersey: the first arrive in the second week of November, they are common by mid November, peak in early February (4.5% of checklists), and most are gone by mid March.

When to look

First arrivalsNov 8-14the second week of November
Common byNov 15-21mid November
PeakFeb 1-7early February
Most gone byMar 15-21mid March

Best: early February. First arrivals the second week of November; most are gone by mid March. Peak: on about 4.5% of New Jersey checklists.

  1. Janpeak season
  2. Febpeak season
  3. Marcommon
  4. Apruncommon
  5. Maynot usually seen
  6. Junnot usually seen
  7. Julnot usually seen
  8. Augnot usually seen
  9. Sepnot usually seen
  10. Octrare
  11. Novcommon
  12. Decpeak season

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

0%2%4%6%Jan 1-7: 3.6% of 28167 checklistsJan 8-14: 3.9% of 20583 checklistsJan 15-21: 3.9% of 19739 checklistsJan 22-31: 4.4% of 24586 checklistsFeb 1-7: 4.5% of 17226 checklistsFeb 8-14: 4.7% of 19567 checklistsFeb 15-21: 3.5% of 26553 checklistsFeb 22-28: 3.4% of 19046 checklistsMar 1-7: 3.3% of 17969 checklistsMar 8-14: 2.9% of 18976 checklistsMar 15-21: 2.2% of 18581 checklistsMar 22-31: 1.4% of 27590 checklistsApr 1-7: 0.8% of 21202 checklistsApr 8-14: 0.4% of 23609 checklistsApr 15-21: 0.1% of 25056 checklistsApr 22-30: 0.1% of 36679 checklistsMay 1-7: 0.1% of 38378 checklistsMay 8-14: 0.1% of 44071 checklistsMay 15-21: 0% of 34076 checklistsMay 22-31: 0% of 32558 checklistsJun 1-7: 0% of 18049 checklistsJun 8-14: 0% of 15597 checklistsJun 15-21: 0% of 14894 checklistsJun 22-30: 0% of 17187 checklistsJul 1-7: 0% of 13406 checklistsJul 8-14: 0% of 12550 checklistsJul 15-21: 0% of 12358 checklistsJul 22-31: 0% of 18382 checklistsAug 1-7: 0% of 13689 checklistsAug 8-14: 0% of 14006 checklistsAug 15-21: 0% of 14483 checklistsAug 22-31: 0% of 23182 checklistsSep 1-7: 0% of 17984 checklistsSep 8-14: 0% of 18320 checklistsSep 15-21: 0% of 20491 checklistsSep 22-30: 0.1% of 26176 checklistsOct 1-7: 0% of 24112 checklistsOct 8-14: 0.1% of 24603 checklistsOct 15-21: 0.1% of 24549 checklistsOct 22-31: 0.1% of 26206 checklistsNov 1-7: 0.4% of 17469 checklistsNov 8-14: 1.0% of 15102 checklistsNov 15-21: 2.1% of 14958 checklistsNov 22-30: 3.1% of 19447 checklistsDec 1-7: 3.4% of 14017 checklistsDec 8-14: 4.0% of 14625 checklistsDec 15-21: 4.3% of 16937 checklistsDec 22-31: 4.1% 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. Sussex CountyBest mid December · 381 checklists that week, 30,305 in all17%
  2. Bergen CountyBest late January · 1992 checklists that week, 73,457 in all11%
  3. Morris CountyBest late December · 1722 checklists that week, 59,212 in all10%
  4. Warren CountyBest mid December · 388 checklists that week, 20,077 in all9.4%
  5. Mercer CountyBest mid December · 1083 checklists that week, 56,614 in all7.5%
  6. Hudson CountyBest the second week of January · 390 checklists that week, 21,191 in all7.4%

Best spots

Share of checklists at the peak
  1. Wallkill River National Wildlife RefugeSussex County, best early December · 30 checklists that week, 2,362 in all50%
  2. Shelter CoveOcean County, best late January · 24 checklists that week, 724 in all48%
  3. Wallkill River National Wildlife Refuge (south)Sussex County, best mid December · 20 checklists that week, 665 in all48%
  4. Troy Meadows PreserveMorris County, best mid December · 22 checklists that week, 2,942 in all48%
  5. West Essex ParkEssex County, best early January · 46 checklists that week, 1,556 in all45%
  6. Great SwampMorris County, best mid January · 44 checklists that week, 1,932 in all43%

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

Best time of day

In New Jersey, the American Tree Sparrow is most often listed on checklists started between 9 and 11 am (1.6% of those checklists).

0%0.5%1%1.5%2%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: 0.9% of 50447 checklists7 am: 1.5% of 118312 checklists8 am: 1.5% of 123273 checklists9 am: 1.7% of 107783 checklists10 am: 1.6% of 97537 checklists11 am: 1.4% of 82427 checklists12 pm: 1.4% of 72581 checklists1 pm: 1.4% of 71478 checklists2 pm: 1.5% of 69994 checklists3 pm: 1.2% of 66822 checklists4 pm: 0.9% of 55950 checklists5 pm: 0.4% of 41360 checklists6 pm: 0.2% 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
January3.6%3.9%3.9%4.4%
February4.5%4.7%3.5%3.4%
March3.3%2.9%2.2%1.4%
April0.8%0.4%0.1%0.1%
May0.1%0.1%0%0%
June0%0%0%0%
July0%0%0%0%
August0%0%0%0%
September0%0%0%0.1%
October0%0.1%0.1%0.1%
November0.4%1.0%2.1%3.1%
December3.4%4.0%4.3%4.1%

Neighboring states

  • Connecticut: arrives early November, 1 week earlier than New Jersey
  • Pennsylvania: arrives the second week of November, in the same week than New Jersey
  • New York: arrives late October, 2 weeks earlier than New Jersey
  • Maryland: arrives mid November, 1 week later than New Jersey

Common questions

When do American Tree Sparrows arrive in New Jersey?
American Tree Sparrows are winter birds in New Jersey: the first arrive in the second week of November, they are common by mid November, peak in early February (4.5% of checklists), and most are gone by mid March.
When do American Tree Sparrows leave New Jersey?
Most American Tree Sparrows have left New Jersey by mid March, when reports fall below half their usual rate. Stragglers are still reported until late March.
When is the best time to see a American Tree Sparrow in New Jersey?
The American Tree Sparrow is reported most often in early February, on about 4.5% of New Jersey checklists.
Where in New Jersey are American Tree Sparrows seen most often?
By county, Sussex County, Bergen County, and Morris County have the highest peak reporting rates for the American Tree Sparrow (counties with at least 200 checklists).