WhenToBird

Mergus serrator · Anatidae

When Do Red-breasted Mergansers Arrive in Texas?

Adult male Red-breasted Merganser
Photo: Peter Chen 2.0, CC BY 4.0 via iNaturalist

Red-breasted Mergansers are winter birds in Texas: they arrive in mid November, peak in late December (1.7% of checklists), and most are gone by the second week of April.

When to look

First arrivalsNov 15-21mid November
Common byNov 15-21mid November
PeakDec 22-31late December
Most gone byApr 8-14the second week of April

Best: late December. First arrivals mid November; most are gone by the second week of April. Peak: on about 1.7% of Texas checklists.

  1. Janpeak season
  2. Febpeak season
  3. Marpeak season
  4. Aprcommon
  5. Mayrare
  6. Junnot usually seen
  7. Julnot usually seen
  8. Augnot usually seen
  9. Sepnot usually seen
  10. Octrare
  11. Novcommon
  12. Decpeak season

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

0%0.5%1%1.5%2%Jan 1-7: 1.7% of 66038 checklistsJan 8-14: 1.7% of 52445 checklistsJan 15-21: 1.6% of 52985 checklistsJan 22-31: 1.6% of 71020 checklistsFeb 1-7: 1.3% of 52306 checklistsFeb 8-14: 1.3% of 55887 checklistsFeb 15-21: 1.2% of 69016 checklistsFeb 22-28: 1.6% of 52998 checklistsMar 1-7: 1.5% of 50836 checklistsMar 8-14: 1.4% of 51749 checklistsMar 15-21: 1.2% of 53731 checklistsMar 22-31: 1.1% of 82049 checklistsApr 1-7: 1.0% of 65854 checklistsApr 8-14: 0.8% of 78434 checklistsApr 15-21: 0.7% of 92302 checklistsApr 22-30: 0.4% of 122878 checklistsMay 1-7: 0.1% of 74592 checklistsMay 8-14: 0.1% of 61008 checklistsMay 15-21: 0.1% of 43365 checklistsMay 22-31: 0.1% of 52736 checklistsJun 1-7: 0.1% of 31643 checklistsJun 8-14: 0.1% of 30131 checklistsJun 15-21: 0.1% of 26802 checklistsJun 22-30: 0.1% of 32822 checklistsJul 1-7: 0.1% of 27213 checklistsJul 8-14: 0.1% of 24555 checklistsJul 15-21: 0% of 24146 checklistsJul 22-31: 0% of 34536 checklistsAug 1-7: 0.1% of 25764 checklistsAug 8-14: 0.1% of 26347 checklistsAug 15-21: 0.1% of 28431 checklistsAug 22-31: 0% of 42838 checklistsSep 1-7: 0% of 35070 checklistsSep 8-14: 0% of 33893 checklistsSep 15-21: 0% of 32572 checklistsSep 22-30: 0.1% of 43771 checklistsOct 1-7: 0.1% of 34143 checklistsOct 8-14: 0% of 37563 checklistsOct 15-21: 0.1% of 36263 checklistsOct 22-31: 0.1% of 49170 checklistsNov 1-7: 0.2% of 43301 checklistsNov 8-14: 0.5% of 48744 checklistsNov 15-21: 0.8% of 42213 checklistsNov 22-30: 1.3% of 54455 checklistsDec 1-7: 1.6% of 40166 checklistsDec 8-14: 1.7% of 41035 checklistsDec 15-21: 1.9% of 46983 checklistsDec 22-31: 1.6% 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. San Patricio CountyBest mid March · 388 checklists that week, 17,002 in all18%
  2. Mitchell CountyBest mid January · 20 checklists that week, 734 in all17%
  3. Reeves CountyBest mid December · 186 checklists that week, 3,930 in all15%
  4. Knox CountyBest late February · 13 checklists that week, 533 in all13%
  5. Hutchinson CountyBest early March · 24 checklists that week, 1,115 in all12%
  6. Baylor CountyBest late February · 13 checklists that week, 537 in all10%

Best spots

Share of checklists at the peak
  1. Sunset Lake (southwest)San Patricio County, best mid March · 49 checklists that week, 1,826 in all72%
  2. Bolivar Flats Shorebird Sanctuary (Point Bolivar)Galveston County, best late January · 44 checklists that week, 878 in all60%
  3. Sunset Lake (Indian Point)Nueces County, best late December · 31 checklists that week, 207 in all56%
  4. Sunset LakeSan Patricio County, best mid March · 63 checklists that week, 2,056 in all54%

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

Best time of day

In Texas, the Red-breasted Merganser is most often listed on checklists started between 1 and 3 pm (1.0% of those checklists).

0%0.5%1%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: 0.5% of 74687 checklists7 am: 0.6% of 285131 checklists8 am: 0.8% of 329960 checklists9 am: 0.8% of 267889 checklists10 am: 0.9% of 218205 checklists11 am: 0.9% of 178879 checklists12 pm: 0.9% of 153722 checklists1 pm: 1.0% of 144662 checklists2 pm: 1.0% of 138578 checklists3 pm: 0.9% of 136878 checklists4 pm: 0.6% of 137550 checklists5 pm: 0.4% of 113599 checklists6 pm: 0.2% of 81743 checklists7 pm: 0.1% 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
January1.7%1.7%1.6%1.6%
February1.3%1.3%1.2%1.6%
March1.5%1.4%1.2%1.1%
April1.0%0.8%0.7%0.4%
May0.1%0.1%0.1%0.1%
June0.1%0.1%0.1%0.1%
July0.1%0.1%0%0%
August0.1%0.1%0.1%0%
September0%0%0%0.1%
October0.1%0%0.1%0.1%
November0.2%0.5%0.8%1.3%
December1.6%1.7%1.9%1.6%

Neighboring states

  • Louisiana: arrives mid November, in the same week than Texas
  • Oklahoma: arrives early November, 2 weeks earlier than Texas
  • Arkansas: arrives early November, 2 weeks earlier than Texas
  • Mississippi: arrives the second week of November, 1 week earlier than Texas

Common questions

When do Red-breasted Mergansers arrive in Texas?
Red-breasted Mergansers are winter birds in Texas: they arrive in mid November, peak in late December (1.7% of checklists), and most are gone by the second week of April.
When do Red-breasted Mergansers leave Texas?
Most Red-breasted Mergansers have left Texas by the second week of April, when reports fall below half their usual rate.
When is the best time to see a Red-breasted Merganser in Texas?
The Red-breasted Merganser is reported most often in late December, on about 1.7% of Texas checklists.
Where in Texas are Red-breasted Mergansers seen most often?
By county, San Patricio County, Mitchell County, and Reeves County have the highest peak reporting rates for the Red-breasted Merganser (counties with at least 200 checklists).