WhenToBird

Molothrus aeneus · Icteridae

When Do Bronzed Cowbirds Arrive in Louisiana?

Adult Bronzed Cowbird
Photo: Jo Roberts, CC BY 4.0 via iNaturalist

Bronzed Cowbirds arrive in Louisiana in early April, peak in early May (2.9% of checklists), and most are gone by mid July.

When to look

First arrivalsApr 1-7early April
Common byApr 1-7early April
PeakMay 1-7early May
Most gone byJul 15-21mid July

Best: early May. First arrivals early April; most are gone by mid July. Peak: on about 2.9% of Louisiana checklists.

  1. Janrare
  2. Febrare
  3. Maruncommon
  4. Aprpeak season
  5. Maypeak season
  6. Junpeak season
  7. Julcommon
  8. Auguncommon
  9. Sepuncommon
  10. Octrare
  11. Novrare
  12. Decrare

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

0%1%2%3%Jan 1-7: 0.2% of 8384 checklistsJan 8-14: 0.2% of 6265 checklistsJan 15-21: 0.2% of 6825 checklistsJan 22-31: 0.1% of 8776 checklistsFeb 1-7: 0.1% of 5956 checklistsFeb 8-14: 0.1% of 6291 checklistsFeb 15-21: 0.1% of 8044 checklistsFeb 22-28: 0.2% of 5946 checklistsMar 1-7: 0.2% of 5981 checklistsMar 8-14: 0.2% of 6307 checklistsMar 15-21: 0.3% of 6747 checklistsMar 22-31: 0.6% of 10487 checklistsApr 1-7: 1.1% of 8037 checklistsApr 8-14: 2.2% of 9577 checklistsApr 15-21: 2.5% of 11372 checklistsApr 22-30: 2.9% of 14344 checklistsMay 1-7: 2.8% of 8193 checklistsMay 8-14: 2.9% of 6823 checklistsMay 15-21: 2.1% of 4818 checklistsMay 22-31: 2.3% of 6206 checklistsJun 1-7: 2.2% of 3660 checklistsJun 8-14: 2.1% of 3455 checklistsJun 15-21: 1.7% of 3084 checklistsJun 22-30: 1.7% of 3904 checklistsJul 1-7: 1.8% of 3240 checklistsJul 8-14: 1.3% of 3235 checklistsJul 15-21: 1.3% of 3167 checklistsJul 22-31: 1.0% of 4328 checklistsAug 1-7: 0.5% of 3192 checklistsAug 8-14: 0.6% of 3394 checklistsAug 15-21: 0.7% of 3502 checklistsAug 22-31: 0.8% of 5658 checklistsSep 1-7: 0.3% of 4366 checklistsSep 8-14: 0.2% of 4648 checklistsSep 15-21: 0.2% of 4369 checklistsSep 22-30: 0.2% of 6418 checklistsOct 1-7: 0.2% of 5375 checklistsOct 8-14: 0.2% of 6213 checklistsOct 15-21: 0.3% of 5553 checklistsOct 22-31: 0.2% of 8879 checklistsNov 1-7: 0.2% of 6231 checklistsNov 8-14: 0.2% of 5011 checklistsNov 15-21: 0.1% of 4856 checklistsNov 22-30: 0.2% of 6696 checklistsDec 1-7: 0.1% of 4530 checklistsDec 8-14: 0.1% of 4883 checklistsDec 15-21: 0.1% of 5833 checklistsDec 22-31: 0.2% 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. Plaquemines ParishBest mid September · 47 checklists that week, 3,374 in all11%
  2. Terrebonne ParishBest early June · 107 checklists that week, 6,857 in all11%
  3. St. Bernard ParishBest the second week of July · 24 checklists that week, 1,331 in all11%
  4. St. Charles ParishBest late June · 12 checklists that week, 969 in all10%
  5. Jefferson ParishBest early May · 813 checklists that week, 25,795 in all8.8%
  6. St. Mary ParishBest the second week of July · 12 checklists that week, 2,241 in all7.1%

Best spots

Share of checklists at the peak
  1. Big Branch Marsh National Wildlife Refuge (Bayou Cochon)St. Tammany Parish, best early May · 27 checklists that week, 1,384 in all40%
  2. Grand Isle State ParkJefferson Parish, best late May · 22 checklists that week, 944 in all40%
  3. Tchefuncte River and Its TributariesSt. Tammany Parish, best the second week of July · 21 checklists that week, 1,001 in all25%

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

Best time of day

In Louisiana, the Bronzed Cowbird is most often listed on checklists started between 6 and 8 am (1.1% of those checklists).

0%0.5%1%1.5%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: 1.2% of 21115 checklists7 am: 1.1% of 38843 checklists8 am: 0.9% of 36306 checklists9 am: 0.9% of 31934 checklists10 am: 0.7% of 27208 checklists11 am: 0.8% of 20733 checklists12 pm: 0.9% of 18505 checklists1 pm: 0.9% of 17383 checklists2 pm: 0.8% of 17422 checklists3 pm: 0.7% of 17005 checklists4 pm: 0.7% of 17170 checklists5 pm: 1.1% of 12536 checklists6 pm: 0.8% 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
January0.2%0.2%0.2%0.1%
February0.1%0.1%0.1%0.2%
March0.2%0.2%0.3%0.6%
April1.1%2.2%2.5%2.9%
May2.8%2.9%2.1%2.3%
June2.2%2.1%1.7%1.7%
July1.8%1.3%1.3%1.0%
August0.5%0.6%0.7%0.8%
September0.3%0.2%0.2%0.2%
October0.2%0.2%0.3%0.2%
November0.2%0.2%0.1%0.2%
December0.1%0.1%0.1%0.2%

Neighboring states

  • Texas: arrives mid March, 2 weeks earlier than Louisiana
  • New Mexico: arrives late April, 3 weeks later than Louisiana
  • Arizona: arrives mid April, 2 weeks later than Louisiana

Common questions

When do Bronzed Cowbirds arrive in Louisiana?
Bronzed Cowbirds arrive in Louisiana in early April, peak in early May (2.9% of checklists), and most are gone by mid July.
When do Bronzed Cowbirds leave Louisiana?
Most Bronzed Cowbirds have left Louisiana by mid July, when reports fall below half their usual rate.
When is the best time to see a Bronzed Cowbird in Louisiana?
The Bronzed Cowbird is reported most often in early May, on about 2.9% of Louisiana checklists.
Where in Louisiana are Bronzed Cowbirds seen most often?
By county, Plaquemines Parish, Terrebonne Parish, and St. Bernard Parish have the highest peak reporting rates for the Bronzed Cowbird (counties with at least 200 checklists).