WhenToBird

Mergus serrator · Anatidae

When Do Red-breasted Mergansers Arrive in Tennessee?

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

Red-breasted Mergansers are winter birds in Tennessee: they arrive in early November, peak in early December (1.9% of checklists), and most are gone by the second week of April.

When to look

First arrivalsNov 1-7early November
Common byNov 1-7early November
PeakDec 1-7early December
Most gone byApr 8-14the second week of April

Best: early December. First arrivals early November; most are gone by the second week of April. Peak: on about 1.9% of Tennessee checklists.

  1. Jancommon
  2. Febcommon
  3. Marcommon
  4. Aprcommon
  5. Mayuncommon
  6. Junnot usually seen
  7. Julnot usually seen
  8. Augnot usually seen
  9. Sepnot usually seen
  10. Octrare
  11. Novpeak season
  12. Decpeak season

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

0%1%2%3%Jan 1-7: 0.6% of 16696 checklistsJan 8-14: 0.8% of 13056 checklistsJan 15-21: 0.8% of 13646 checklistsJan 22-31: 0.9% of 18071 checklistsFeb 1-7: 0.5% of 13342 checklistsFeb 8-14: 0.6% of 14316 checklistsFeb 15-21: 0.7% of 20395 checklistsFeb 22-28: 1.0% of 13129 checklistsMar 1-7: 1.0% of 12701 checklistsMar 8-14: 1.2% of 12789 checklistsMar 15-21: 1.7% of 13599 checklistsMar 22-31: 1.2% of 20293 checklistsApr 1-7: 0.8% of 15779 checklistsApr 8-14: 0.5% of 16646 checklistsApr 15-21: 0.3% of 18625 checklistsApr 22-30: 0.4% of 26689 checklistsMay 1-7: 0.3% of 21054 checklistsMay 8-14: 0.1% of 19954 checklistsMay 15-21: 0.1% of 14494 checklistsMay 22-31: 0.1% of 17790 checklistsJun 1-7: 0% of 11344 checklistsJun 8-14: 0% of 11049 checklistsJun 15-21: 0.1% of 9625 checklistsJun 22-30: 0.1% of 11522 checklistsJul 1-7: 0% of 9208 checklistsJul 8-14: 0% of 8814 checklistsJul 15-21: 0% of 8887 checklistsJul 22-31: 0% of 12739 checklistsAug 1-7: 0% of 9632 checklistsAug 8-14: 0% of 9514 checklistsAug 15-21: 0% of 9619 checklistsAug 22-31: 0% of 14227 checklistsSep 1-7: 0% of 11988 checklistsSep 8-14: 0% of 11660 checklistsSep 15-21: 0% of 11774 checklistsSep 22-30: 0% of 15658 checklistsOct 1-7: 0% of 12641 checklistsOct 8-14: 0% of 12389 checklistsOct 15-21: 0.1% of 10249 checklistsOct 22-31: 0.1% of 14085 checklistsNov 1-7: 0.2% of 10700 checklistsNov 8-14: 1.3% of 10709 checklistsNov 15-21: 1.4% of 9955 checklistsNov 22-30: 1.7% of 13423 checklistsDec 1-7: 1.8% of 10106 checklistsDec 8-14: 2.2% of 10478 checklistsDec 15-21: 1.4% of 12177 checklistsDec 22-31: 0.6% of 17397 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 Tennessee 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 Tennessee

Best counties

Share of checklists at the peak
  1. Hardin CountyBest mid March · 62 checklists that week, 2,710 in all14%
  2. Henry CountyBest mid December · 278 checklists that week, 5,668 in all12%
  3. Obion CountyBest late November · 51 checklists that week, 2,011 in all11%
  4. Benton CountyBest early December · 34 checklists that week, 2,202 in all11%
  5. Rhea CountyBest early March · 55 checklists that week, 2,708 in all9.1%
  6. Humphreys CountyBest late November · 100 checklists that week, 5,858 in all9.1%

Best spots

Share of checklists at the peak
  1. Seven Points Public Use AreaDavidson County, best the second week of March · 31 checklists that week, 486 in all32%
  2. Booker T WashingtonHamilton County, best early December · 81 checklists that week, 1,440 in all29%
  3. Maloney Rd ParkKnox County, best mid February · 26 checklists that week, 225 in all28%
  4. Tennessee National Wildlife RefugeHumphreys County, best the second week of December · 24 checklists that week, 779 in all28%
  5. Anderson Road Public Use AreaDavidson County, best mid November · 24 checklists that week, 548 in all27%
  6. Tennessee National Wildlife Refuge (northwest)Henry County, best mid January · 21 checklists that week, 267 in all26%

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

Best time of day

In Tennessee, the Red-breasted Merganser is most often listed on checklists started between 12 and 2 pm (0.7% of those checklists).

0%0.5%1%12 am: too few checklists (224) to judge1 am: too few checklists (253) to judge2 am: too few checklists (245) to judge3 am: too few checklists (267) to judge4 am: too few checklists (582) to judge5 am: too few checklists (5688) to judge6 am: 0.6% of 36828 checklists7 am: 0.4% of 72816 checklists8 am: 0.4% of 76910 checklists9 am: 0.5% of 69071 checklists10 am: 0.5% of 60943 checklists11 am: 0.6% of 52311 checklists12 pm: 0.7% of 46524 checklists1 pm: 0.8% of 41133 checklists2 pm: 0.7% of 40305 checklists3 pm: 0.6% of 41013 checklists4 pm: 0.6% of 40029 checklists5 pm: 0.3% of 29775 checklists6 pm: 0.1% of 20977 checklists7 pm: too few checklists (12529) to judge8 pm: too few checklists (4456) to judge9 pm: too few checklists (1056) to judge10 pm: too few checklists (445) to judge11 pm: too few checklists (252) 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
January0.6%0.8%0.8%0.9%
February0.5%0.6%0.7%1.0%
March1.0%1.2%1.7%1.2%
April0.8%0.5%0.3%0.4%
May0.3%0.1%0.1%0.1%
June0%0%0.1%0.1%
July0%0%0%0%
August0%0%0%0%
September0%0%0%0%
October0%0%0.1%0.1%
November0.2%1.3%1.4%1.7%
December1.8%2.2%1.4%0.6%

Neighboring states

  • Kentucky: arrives the second week of November, 1 week later than Tennessee
  • Georgia: arrives the second week of November, 1 week later than Tennessee
  • Alabama: arrives mid November, 2 weeks later than Tennessee
  • Indiana: arrives early November, in the same week than Tennessee

Common questions

When do Red-breasted Mergansers arrive in Tennessee?
Red-breasted Mergansers are winter birds in Tennessee: they arrive in early November, peak in early December (1.9% of checklists), and most are gone by the second week of April.
When do Red-breasted Mergansers leave Tennessee?
Most Red-breasted Mergansers have left Tennessee 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 Tennessee?
The Red-breasted Merganser is reported most often in early December, on about 1.9% of Tennessee checklists.
Where in Tennessee are Red-breasted Mergansers seen most often?
By county, Hardin County, Henry County, and Obion County have the highest peak reporting rates for the Red-breasted Merganser (counties with at least 200 checklists).