WhenToBird

Molothrus ater · Icteridae

When Do Brown-headed Cowbirds Arrive in Texas?

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

Brown-headed Cowbirds are in Texas all year, but most are here in spring: numbers build from the second week of March, peak in the second week of May (20% of checklists), and fall back by the second week of July. In the quietest week (the second week of September) they are still on about 2.8% of checklists.

When to look

Numbers buildMar 8-14the second week of March
PeakMay 8-14the second week of May
Fall back byJul 8-14the second week of July
FewestSep 8-14the second week of September

Best: the second week of May. Here all year; numbers build from the second week of March and fall back by the second week of July. Peak: on about 20% of Texas checklists.

  1. Januncommon
  2. Febcommon
  3. Marcommon
  4. Aprpeak season
  5. Maypeak season
  6. Junpeak season
  7. Julpeak season
  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: 4.0% of 66038 checklistsJan 8-14: 4.1% of 52445 checklistsJan 15-21: 4.6% of 52985 checklistsJan 22-31: 4.6% of 71020 checklistsFeb 1-7: 5.9% of 52306 checklistsFeb 8-14: 6.3% of 55887 checklistsFeb 15-21: 7.2% of 69016 checklistsFeb 22-28: 8.1% of 52998 checklistsMar 1-7: 10% of 50836 checklistsMar 8-14: 11% of 51749 checklistsMar 15-21: 13% of 53731 checklistsMar 22-31: 15% of 82049 checklistsApr 1-7: 16% of 65854 checklistsApr 8-14: 17% of 78434 checklistsApr 15-21: 18% of 92302 checklistsApr 22-30: 20% of 122878 checklistsMay 1-7: 20% of 74592 checklistsMay 8-14: 20% of 61008 checklistsMay 15-21: 20% of 43365 checklistsMay 22-31: 19% of 52736 checklistsJun 1-7: 18% of 31643 checklistsJun 8-14: 17% of 30131 checklistsJun 15-21: 16% of 26802 checklistsJun 22-30: 16% of 32822 checklistsJul 1-7: 16% of 27213 checklistsJul 8-14: 13% of 24555 checklistsJul 15-21: 11% of 24146 checklistsJul 22-31: 6.9% of 34536 checklistsAug 1-7: 5.1% of 25764 checklistsAug 8-14: 4.2% of 26347 checklistsAug 15-21: 3.6% of 28431 checklistsAug 22-31: 3.1% of 42838 checklistsSep 1-7: 2.9% of 35070 checklistsSep 8-14: 2.5% of 33893 checklistsSep 15-21: 2.9% of 32572 checklistsSep 22-30: 3.7% of 43771 checklistsOct 1-7: 4.3% of 34143 checklistsOct 8-14: 4.7% of 37563 checklistsOct 15-21: 4.8% of 36263 checklistsOct 22-31: 5.1% of 49170 checklistsNov 1-7: 4.7% of 43301 checklistsNov 8-14: 4.4% of 48744 checklistsNov 15-21: 4.6% of 42213 checklistsNov 22-30: 3.9% of 54455 checklistsDec 1-7: 4.1% of 40166 checklistsDec 8-14: 3.9% of 41035 checklistsDec 15-21: 3.9% of 46983 checklistsDec 22-31: 3.8% of 73015 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 Texas 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 Texas

Best counties

Share of checklists at the peak
  1. Bee CountyBest the second week of May · 115 checklists that week, 4,609 in all76%
  2. Duval CountyBest early June · 14 checklists that week, 1,580 in all63%
  3. Karnes CountyBest late April · 49 checklists that week, 1,746 in all59%
  4. Red River CountyBest late May · 78 checklists that week, 1,179 in all59%
  5. Gonzales CountyBest mid May · 117 checklists that week, 8,706 in all59%
  6. Frio CountyBest the second week of May · 40 checklists that week, 967 in all56%

Best spots

Share of checklists at the peak
  1. Meadowlakes Number 2 LakeBurnet County, best late May · 20 checklists that week, 693 in all98%
  2. TolucaHidalgo County, best the second week of November · 35 checklists that week, 839 in all94%
  3. Guadalupe River State Park (2)Comal County, best early May · 27 checklists that week, 418 in all89%
  4. Pleasant Acres LakeSmith County, best late April · 31 checklists that week, 355 in all85%

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

Best time of day

In Texas, the Brown-headed Cowbird is most often listed on checklists started between 6 and 8 am (17% of those checklists).

0%5%10%15%20%12 am: too few checklists (898) to judge1 am: too few checklists (756) to judge2 am: too few checklists (663) to judge3 am: too few checklists (741) to judge4 am: too few checklists (1537) to judge5 am: too few checklists (6113) to judge6 am: 18% of 74687 checklists7 am: 16% of 285131 checklists8 am: 13% of 329960 checklists9 am: 11% of 267889 checklists10 am: 8.8% of 218205 checklists11 am: 7.5% of 178879 checklists12 pm: 6.9% of 153722 checklists1 pm: 6.7% of 144662 checklists2 pm: 6.4% of 138578 checklists3 pm: 6.6% of 136878 checklists4 pm: 6.8% of 137550 checklists5 pm: 7.2% of 113599 checklists6 pm: 8.2% of 81743 checklists7 pm: 7.3% of 53396 checklists8 pm: too few checklists (17221) to judge9 pm: too few checklists (4048) to judge10 pm: too few checklists (1965) to judge11 pm: too few checklists (990) 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
January4.0%4.1%4.6%4.6%
February5.9%6.3%7.2%8.1%
March10%11%13%15%
April16%17%18%20%
May20%20%20%19%
June18%17%16%16%
July16%13%11%6.9%
August5.1%4.2%3.6%3.1%
September2.9%2.5%2.9%3.7%
October4.3%4.7%4.8%5.1%
November4.7%4.4%4.6%3.9%
December4.1%3.9%3.9%3.8%

Neighboring states

  • Louisiana: arrives early March, 1 week earlier than Texas
  • Oklahoma: arrives early January, 9 weeks earlier than Texas
  • Arkansas: arrives mid March, 1 week later than Texas
  • Mississippi: arrives the second week of March, in the same week than Texas

Common questions

When do Brown-headed Cowbirds arrive in Texas?
Brown-headed Cowbirds are in Texas all year, but most are here in spring: numbers build from the second week of March, peak in the second week of May (20% of checklists), and fall back by the second week of July. In the quietest week (the second week of September) they are still on about 2.8% of checklists.
When do Brown-headed Cowbirds leave Texas?
Brown-headed Cowbirds never fully leave Texas: numbers fall back below half their usual rate by the second week of July, but some are still reported in every week, about 2.8% of checklists at the low.
When is the best time to see a Brown-headed Cowbird in Texas?
The Brown-headed Cowbird is reported most often in the second week of May, on about 20% of Texas checklists.
Where in Texas are Brown-headed Cowbirds seen most often?
By county, Bee County, Duval County, and Karnes County have the highest peak reporting rates for the Brown-headed Cowbird (counties with at least 200 checklists).