WhenToBird

Molothrus ater · Icteridae

When Do Brown-headed Cowbirds Arrive in Louisiana?

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

Brown-headed Cowbirds are in Louisiana all year, but most are here in spring: numbers build from early March, peak in mid April (26% of checklists), and fall back by early July. In the quietest week (the second week of September) they are still on about 3.6% of checklists.

When to look

Numbers buildMar 1-7early March
PeakApr 15-21mid April
Fall back byJul 1-7early July
FewestSep 8-14the second week of September

Best: mid April. Here all year; numbers build from early March and fall back by early July. Peak: on about 26% of Louisiana checklists.

  1. Januncommon
  2. Febcommon
  3. Marpeak season
  4. Aprpeak season
  5. Maypeak season
  6. Junpeak season
  7. Julcommon
  8. Auguncommon
  9. Sepuncommon
  10. Octuncommon
  11. Novuncommon
  12. Decuncommon

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

0%10%20%30%Jan 1-7: 7.1% of 8384 checklistsJan 8-14: 6.2% of 6265 checklistsJan 15-21: 7.5% of 6825 checklistsJan 22-31: 8.3% of 8776 checklistsFeb 1-7: 10% of 5956 checklistsFeb 8-14: 11% of 6291 checklistsFeb 15-21: 13% of 8044 checklistsFeb 22-28: 15% of 5946 checklistsMar 1-7: 17% of 5981 checklistsMar 8-14: 18% of 6307 checklistsMar 15-21: 19% of 6747 checklistsMar 22-31: 21% of 10487 checklistsApr 1-7: 23% of 8037 checklistsApr 8-14: 26% of 9577 checklistsApr 15-21: 26% of 11372 checklistsApr 22-30: 27% of 14344 checklistsMay 1-7: 25% of 8193 checklistsMay 8-14: 24% of 6823 checklistsMay 15-21: 23% of 4818 checklistsMay 22-31: 24% of 6206 checklistsJun 1-7: 23% of 3660 checklistsJun 8-14: 22% of 3455 checklistsJun 15-21: 21% of 3084 checklistsJun 22-30: 20% of 3904 checklistsJul 1-7: 17% of 3240 checklistsJul 8-14: 13% of 3235 checklistsJul 15-21: 10% of 3167 checklistsJul 22-31: 5.7% of 4328 checklistsAug 1-7: 4.4% of 3192 checklistsAug 8-14: 5.2% of 3394 checklistsAug 15-21: 4.7% of 3502 checklistsAug 22-31: 3.9% of 5658 checklistsSep 1-7: 3.3% of 4366 checklistsSep 8-14: 3.5% of 4648 checklistsSep 15-21: 4.0% of 4369 checklistsSep 22-30: 5.3% of 6418 checklistsOct 1-7: 8.0% of 5375 checklistsOct 8-14: 8.3% of 6213 checklistsOct 15-21: 8.8% of 5553 checklistsOct 22-31: 9.4% of 8879 checklistsNov 1-7: 9.2% of 6231 checklistsNov 8-14: 7.4% of 5011 checklistsNov 15-21: 7.3% of 4856 checklistsNov 22-30: 6.6% of 6696 checklistsDec 1-7: 5.8% of 4530 checklistsDec 8-14: 6.3% of 4883 checklistsDec 15-21: 6.8% of 5833 checklistsDec 22-31: 6.3% of 9940 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 Louisiana 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 Louisiana

Best counties

Share of checklists at the peak
  1. East Carroll ParishBest early May · 14 checklists that week, 317 in all86%
  2. Concordia ParishBest early June · 19 checklists that week, 983 in all72%
  3. Iberville ParishBest late May · 44 checklists that week, 2,343 in all70%
  4. Catahoula ParishBest late May · 33 checklists that week, 464 in all66%
  5. La Salle ParishBest late May · 49 checklists that week, 847 in all61%
  6. Webster ParishBest mid June · 11 checklists that week, 418 in all59%

Best spots

Share of checklists at the peak
  1. City Park LakeEast Baton Rouge Parish, best early April · 23 checklists that week, 1,057 in all91%
  2. Lake ComeauxSt. Martin Parish, best late April · 23 checklists that week, 144 in all83%
  3. Burbank Soccer ComplexEast Baton Rouge Parish, best mid February · 32 checklists that week, 304 in all76%

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

Best time of day

In Louisiana, the Brown-headed Cowbird is most often listed on checklists started between 6 and 8 am (19% of those checklists).

0%5%10%15%20%12 am: too few checklists (110) to judge1 am: too few checklists (95) to judge2 am: too few checklists (78) to judge3 am: too few checklists (145) to judge4 am: too few checklists (266) to judge5 am: too few checklists (2981) to judge6 am: 18% of 21115 checklists7 am: 20% of 38843 checklists8 am: 18% of 36306 checklists9 am: 15% of 31934 checklists10 am: 12% of 27208 checklists11 am: 11% of 20733 checklists12 pm: 11% of 18505 checklists1 pm: 11% of 17383 checklists2 pm: 9.9% of 17422 checklists3 pm: 9.4% of 17005 checklists4 pm: 9.9% of 17170 checklists5 pm: 11% of 12536 checklists6 pm: 11% of 8080 checklists7 pm: too few checklists (3798) to judge8 pm: too few checklists (676) to judge9 pm: too few checklists (311) to judge10 pm: too few checklists (206) to judge11 pm: too few checklists (93) 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
January7.1%6.2%7.5%8.3%
February10%11%13%15%
March17%18%19%21%
April23%26%26%27%
May25%24%23%24%
June23%22%21%20%
July17%13%10%5.7%
August4.4%5.2%4.7%3.9%
September3.3%3.5%4.0%5.3%
October8.0%8.3%8.8%9.4%
November9.2%7.4%7.3%6.6%
December5.8%6.3%6.8%6.3%

Neighboring states

  • Mississippi: arrives the second week of March, 1 week later than Louisiana
  • Alabama: arrives early March, in the same week than Louisiana
  • Texas: arrives the second week of March, 1 week later than Louisiana
  • Arkansas: arrives mid March, 2 weeks later than Louisiana

Common questions

When do Brown-headed Cowbirds arrive in Louisiana?
Brown-headed Cowbirds are in Louisiana all year, but most are here in spring: numbers build from early March, peak in mid April (26% of checklists), and fall back by early July. In the quietest week (the second week of September) they are still on about 3.6% of checklists.
When do Brown-headed Cowbirds leave Louisiana?
Brown-headed Cowbirds never fully leave Louisiana: numbers fall back below half their usual rate by early July, but some are still reported in every week, about 3.6% of checklists at the low.
When is the best time to see a Brown-headed Cowbird in Louisiana?
The Brown-headed Cowbird is reported most often in mid April, on about 26% of Louisiana checklists.
Where in Louisiana are Brown-headed Cowbirds seen most often?
By county, East Carroll Parish, Concordia Parish, and Iberville Parish have the highest peak reporting rates for the Brown-headed Cowbird (counties with at least 200 checklists).