WhenToBird

Helmitheros vermivorum · Parulidae

When Do Worm-eating Warblers Arrive in Louisiana?

Adult Worm-eating Warbler
Photo: kirk gardner, CC BY 4.0 via iNaturalist

Worm-eating Warblers mostly pass through Louisiana: the first show up in late March, they are common by early April, peak in the second week of April (4.0% of checklists), and most are gone by early May.

When to look

First arrivalsMar 22-31late March
Common byApr 1-7early April
PeakApr 8-14the second week of April
Most gone byMay 1-7early May

Best: the second week of April. First arrivals late March; most are gone by early May. Peak: on about 4.0% of Louisiana checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Maruncommon
  4. Aprpeak season
  5. Mayuncommon
  6. Jununcommon
  7. Julrare
  8. Auguncommon
  9. Sepuncommon
  10. Octrare
  11. Novnot usually seen
  12. Decnot usually seen

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

0%2%4%6%Jan 1-7: 0% of 8384 checklistsJan 8-14: 0% of 6265 checklistsJan 15-21: 0% of 6825 checklistsJan 22-31: 0% of 8776 checklistsFeb 1-7: 0% of 5956 checklistsFeb 8-14: 0% of 6291 checklistsFeb 15-21: 0% of 8044 checklistsFeb 22-28: 0% of 5946 checklistsMar 1-7: 0% of 5981 checklistsMar 8-14: 0% of 6307 checklistsMar 15-21: 0.2% of 6747 checklistsMar 22-31: 1.4% of 10487 checklistsApr 1-7: 2.5% of 8037 checklistsApr 8-14: 4.1% of 9577 checklistsApr 15-21: 5.0% of 11372 checklistsApr 22-30: 2.3% of 14344 checklistsMay 1-7: 0.9% of 8193 checklistsMay 8-14: 0.4% of 6823 checklistsMay 15-21: 0.5% of 4818 checklistsMay 22-31: 0.7% of 6206 checklistsJun 1-7: 0.7% of 3660 checklistsJun 8-14: 0.8% of 3455 checklistsJun 15-21: 0.4% of 3084 checklistsJun 22-30: 0.3% of 3904 checklistsJul 1-7: 0.2% of 3240 checklistsJul 8-14: 0.2% of 3235 checklistsJul 15-21: 0.1% of 3167 checklistsJul 22-31: 0.1% of 4328 checklistsAug 1-7: 0.2% of 3192 checklistsAug 8-14: 0.3% of 3394 checklistsAug 15-21: 0.5% of 3502 checklistsAug 22-31: 0.6% of 5658 checklistsSep 1-7: 0.9% of 4366 checklistsSep 8-14: 0.5% of 4648 checklistsSep 15-21: 1.0% of 4369 checklistsSep 22-30: 0.7% of 6418 checklistsOct 1-7: 0.5% of 5375 checklistsOct 8-14: 0.2% of 6213 checklistsOct 15-21: 0.1% of 5553 checklistsOct 22-31: 0.1% of 8879 checklistsNov 1-7: 0.1% of 6231 checklistsNov 8-14: 0% of 5011 checklistsNov 15-21: 0% of 4856 checklistsNov 22-30: 0% of 6696 checklistsDec 1-7: 0% of 4530 checklistsDec 8-14: 0% of 4883 checklistsDec 15-21: 0% of 5833 checklistsDec 22-31: 0% 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.

Embed this map on your site

Where in Louisiana

Best counties

Share of checklists at the peak
  1. Catahoula ParishBest late May · 33 checklists that week, 464 in all34%
  2. La Salle ParishBest the second week of April · 12 checklists that week, 847 in all24%
  3. Webster ParishBest mid June · 11 checklists that week, 418 in all14%
  4. Cameron ParishBest the second week of April · 813 checklists that week, 17,943 in all13%
  5. Winn ParishBest early June · 11 checklists that week, 348 in all11%
  6. Union ParishBest mid June · 27 checklists that week, 2,155 in all11%

Best spots

Share of checklists at the peak
  1. Grand Isle (northeast)Jefferson Parish, best the second week of April · 158 checklists that week, 1,232 in all34%
  2. Grand Isle (north)Jefferson Parish, best mid April · 33 checklists that week, 160 in all22%
  3. Grand IsleJefferson Parish, best the second week of April · 230 checklists that week, 1,519 in all18%

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

Best time of day

In Louisiana, the Worm-eating Warbler is most often listed on checklists started between 2 and 4 pm (1.0% of those checklists).

0%0.5%1%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: 0.6% of 21115 checklists7 am: 0.8% of 38843 checklists8 am: 0.8% of 36306 checklists9 am: 0.7% of 31934 checklists10 am: 0.8% of 27208 checklists11 am: 0.7% of 20733 checklists12 pm: 0.6% of 18505 checklists1 pm: 0.8% of 17383 checklists2 pm: 1.0% of 17422 checklists3 pm: 0.9% of 17005 checklists4 pm: 0.9% of 17170 checklists5 pm: 0.7% of 12536 checklists6 pm: 0.3% 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%0%0%0%
February0%0%0%0%
March0%0%0.2%1.4%
April2.5%4.1%5.0%2.3%
May0.9%0.4%0.5%0.7%
June0.7%0.8%0.4%0.3%
July0.2%0.2%0.1%0.1%
August0.2%0.3%0.5%0.6%
September0.9%0.5%1.0%0.7%
October0.5%0.2%0.1%0.1%
November0.1%0%0%0%
December0%0%0%0%

Neighboring states

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

Common questions

When do Worm-eating Warblers arrive in Louisiana?
Worm-eating Warblers mostly pass through Louisiana: the first show up in late March, they are common by early April, peak in the second week of April (4.0% of checklists), and most are gone by early May.
When do Worm-eating Warblers leave Louisiana?
Most Worm-eating Warblers have left Louisiana by early May, when reports fall below half their usual rate.
When is the best time to see a Worm-eating Warbler in Louisiana?
The Worm-eating Warbler is reported most often in the second week of April, on about 4.0% of Louisiana checklists.
Where in Louisiana are Worm-eating Warblers seen most often?
By county, Catahoula Parish, La Salle Parish, and Webster Parish have the highest peak reporting rates for the Worm-eating Warbler (counties with at least 200 checklists).