WhenToBird

Molothrus ater · Icteridae

When Do Brown-headed Cowbirds Arrive in New York?

Adult female Brown-headed Cowbird
Photo: Nicole, CC BY 4.0 via iNaturalist

Brown-headed Cowbirds reach New York in mid February, are common by late March, peak in late April (26% of checklists), and most are gone by the second week of July.

When to look

First arrivalsFeb 15-21mid February
Common byMar 22-31late March
PeakApr 22-30late April
Most gone byJul 8-14the second week of July

Best: late April. First arrivals mid February; most are gone by the second week of July. Peak: on about 26% of New York checklists.

  1. Janrare
  2. Febrare
  3. Marcommon
  4. Aprpeak season
  5. Maypeak season
  6. Juncommon
  7. Julcommon
  8. Auguncommon
  9. Seprare
  10. Octrare
  11. Novrare
  12. Decrare

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

0%10%20%30%Jan 1-7: 1.2% of 66410 checklistsJan 8-14: 1.4% of 49310 checklistsJan 15-21: 1.4% of 49919 checklistsJan 22-31: 1.6% of 62513 checklistsFeb 1-7: 1.4% of 43526 checklistsFeb 8-14: 1.6% of 49753 checklistsFeb 15-21: 2.1% of 65147 checklistsFeb 22-28: 2.9% of 50173 checklistsMar 1-7: 3.7% of 50325 checklistsMar 8-14: 5.2% of 55371 checklistsMar 15-21: 7.3% of 56293 checklistsMar 22-31: 11% of 82677 checklistsApr 1-7: 15% of 65295 checklistsApr 8-14: 21% of 73080 checklistsApr 15-21: 24% of 73857 checklistsApr 22-30: 27% of 106093 checklistsMay 1-7: 27% of 102772 checklistsMay 8-14: 24% of 110051 checklistsMay 15-21: 23% of 94797 checklistsMay 22-31: 20% of 101272 checklistsJun 1-7: 18% of 59471 checklistsJun 8-14: 17% of 55497 checklistsJun 15-21: 17% of 51761 checklistsJun 22-30: 16% of 59219 checklistsJul 1-7: 14% of 48226 checklistsJul 8-14: 12% of 42315 checklistsJul 15-21: 8.4% of 40637 checklistsJul 22-31: 5.2% of 57183 checklistsAug 1-7: 4.3% of 40461 checklistsAug 8-14: 4.3% of 39880 checklistsAug 15-21: 4.0% of 41146 checklistsAug 22-31: 3.5% of 63381 checklistsSep 1-7: 2.6% of 48640 checklistsSep 8-14: 2.3% of 47882 checklistsSep 15-21: 2.0% of 49063 checklistsSep 22-30: 2.3% of 57906 checklistsOct 1-7: 2.8% of 48447 checklistsOct 8-14: 2.8% of 51901 checklistsOct 15-21: 3.0% of 46717 checklistsOct 22-31: 2.7% of 61992 checklistsNov 1-7: 2.4% of 44593 checklistsNov 8-14: 2.1% of 42566 checklistsNov 15-21: 2.1% of 39675 checklistsNov 22-30: 1.5% of 51197 checklistsDec 1-7: 1.8% of 36567 checklistsDec 8-14: 1.7% of 37254 checklistsDec 15-21: 1.7% of 43754 checklistsDec 22-31: 1.4% of 62470 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 York 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 York

Best counties

Share of checklists at the peak
  1. Orleans CountyBest early May · 599 checklists that week, 16,706 in all48%
  2. Columbia CountyBest late April · 996 checklists that week, 28,454 in all41%
  3. Livingston CountyBest early May · 1094 checklists that week, 29,051 in all39%
  4. Dutchess CountyBest early May · 2835 checklists that week, 76,123 in all38%
  5. Cayuga CountyBest late April · 671 checklists that week, 20,184 in all38%
  6. Wyoming CountyBest early May · 397 checklists that week, 11,458 in all38%

Best spots

Share of checklists at the peak
  1. Nuclear LakeDutchess County, best the second week of May · 20 checklists that week, 248 in all84%
  2. Van KeurensDutchess County, best mid April · 20 checklists that week, 780 in all83%
  3. Lakeside Beach State ParkOrleans County, best early May · 40 checklists that week, 1,060 in all82%
  4. Hamlin Beach State ParkMonroe County, best mid April · 32 checklists that week, 2,133 in all81%
  5. NormansvilleAlbany County, best early May · 54 checklists that week, 866 in all81%
  6. Jones Beach State ParkNassau County, best late April · 23 checklists that week, 1,378 in all80%

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

Best time of day

In New York, the Brown-headed Cowbird is most often listed on checklists started between 6 and 8 am (18% of those checklists).

0%10%20%30%12 am: too few checklists (1146) to judge1 am: too few checklists (1055) to judge2 am: too few checklists (1121) to judge3 am: too few checklists (1353) to judge4 am: too few checklists (4785) to judge5 am: too few checklists (32052) to judge6 am: 22% of 124869 checklists7 am: 16% of 298506 checklists8 am: 13% of 337334 checklists9 am: 11% of 307787 checklists10 am: 8.6% of 270801 checklists11 am: 7.1% of 233238 checklists12 pm: 6.7% of 213830 checklists1 pm: 6.1% of 193321 checklists2 pm: 5.7% of 180741 checklists3 pm: 5.6% of 170348 checklists4 pm: 6.2% of 147224 checklists5 pm: 7.9% of 111962 checklists6 pm: 8.6% of 78261 checklists7 pm: too few checklists (44425) to judge8 pm: too few checklists (15648) to judge9 pm: too few checklists (4795) to judge10 pm: too few checklists (2454) to judge11 pm: too few checklists (1378) 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
January1.2%1.4%1.4%1.6%
February1.4%1.6%2.1%2.9%
March3.7%5.2%7.3%11%
April15%21%24%27%
May27%24%23%20%
June18%17%17%16%
July14%12%8.4%5.2%
August4.3%4.3%4.0%3.5%
September2.6%2.3%2.0%2.3%
October2.8%2.8%3.0%2.7%
November2.4%2.1%2.1%1.5%
December1.8%1.7%1.7%1.4%

Neighboring states

  • Connecticut: arrives mid January, 4 weeks earlier than New York
  • New Jersey: arrives late March, 5 weeks later than New York
  • Pennsylvania: arrives the second week of February, 1 week earlier than New York
  • Vermont: arrives early March, 2 weeks later than New York

Common questions

When do Brown-headed Cowbirds arrive in New York?
Brown-headed Cowbirds reach New York in mid February, are common by late March, peak in late April (26% of checklists), and most are gone by the second week of July.
When do Brown-headed Cowbirds leave New York?
Most Brown-headed Cowbirds have left New York by the second week of July, when reports fall below half their usual rate. Stragglers are still reported until mid November.
When is the best time to see a Brown-headed Cowbird in New York?
The Brown-headed Cowbird is reported most often in late April, on about 26% of New York checklists.
Where in New York are Brown-headed Cowbirds seen most often?
By county, Orleans County, Columbia County, and Livingston County have the highest peak reporting rates for the Brown-headed Cowbird (counties with at least 200 checklists).