WhenToBird

Bucephala albeola · Anatidae

When Do Buffleheads Arrive in Iowa?

Adult Bufflehead
Photo: Robert Harris, CC BY 4.0 via iNaturalist

Buffleheads are winter birds in Iowa: the first arrive in the second week of February, they are common by late February, peak in late March (19% of checklists), and most are gone by late April.

When to look

First arrivalsFeb 8-14the second week of February
Common byFeb 22-28late February
PeakMar 22-31late March
Most gone byApr 22-30late April

Best: late March. First arrivals the second week of February; most are gone by late April. Peak: on about 19% of Iowa checklists.

  1. Janrare
  2. Febuncommon
  3. Marpeak season
  4. Aprpeak season
  5. Mayrare
  6. Junnot usually seen
  7. Julnot usually seen
  8. Augnot usually seen
  9. Sepnot usually seen
  10. Octuncommon
  11. Novcommon
  12. Decuncommon

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

0%10%20%30%Jan 1-7: 0.8% of 5551 checklistsJan 8-14: 0.5% of 3498 checklistsJan 15-21: 0.2% of 3803 checklistsJan 22-31: 0.3% of 4807 checklistsFeb 1-7: 0.5% of 3613 checklistsFeb 8-14: 0.7% of 4173 checklistsFeb 15-21: 1.6% of 5796 checklistsFeb 22-28: 5.0% of 4394 checklistsMar 1-7: 11% of 5295 checklistsMar 8-14: 15% of 5679 checklistsMar 15-21: 20% of 5418 checklistsMar 22-31: 21% of 8613 checklistsApr 1-7: 18% of 6970 checklistsApr 8-14: 12% of 7511 checklistsApr 15-21: 8.4% of 8321 checklistsApr 22-30: 3.7% of 11976 checklistsMay 1-7: 1.0% of 11725 checklistsMay 8-14: 0.3% of 12626 checklistsMay 15-21: 0.2% of 9372 checklistsMay 22-31: 0.1% of 10330 checklistsJun 1-7: 0% of 5472 checklistsJun 8-14: 0.1% of 4568 checklistsJun 15-21: 0% of 3870 checklistsJun 22-30: 0% of 4780 checklistsJul 1-7: 0.1% of 4201 checklistsJul 8-14: 0.1% of 3605 checklistsJul 15-21: 0% of 3621 checklistsJul 22-31: 0% of 5093 checklistsAug 1-7: 0% of 3931 checklistsAug 8-14: 0% of 3488 checklistsAug 15-21: 0% of 3802 checklistsAug 22-31: 0% of 6293 checklistsSep 1-7: 0% of 5328 checklistsSep 8-14: 0% of 4622 checklistsSep 15-21: 0% of 4367 checklistsSep 22-30: 0.1% of 6086 checklistsOct 1-7: 0.1% of 4708 checklistsOct 8-14: 0.3% of 4791 checklistsOct 15-21: 0.8% of 4429 checklistsOct 22-31: 3.9% of 5633 checklistsNov 1-7: 5.7% of 4090 checklistsNov 8-14: 11% of 3416 checklistsNov 15-21: 9.8% of 3398 checklistsNov 22-30: 9.0% of 4679 checklistsDec 1-7: 6.6% of 3442 checklistsDec 8-14: 4.3% of 3322 checklistsDec 15-21: 2.6% of 4619 checklistsDec 22-31: 1.1% of 5113 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 Iowa 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 Iowa

Best counties

Share of checklists at the peak
  1. Worth CountyBest late March · 10 checklists that week, 333 in all59%
  2. Hancock CountyBest mid March · 11 checklists that week, 449 in all56%
  3. Palo Alto CountyBest early April · 11 checklists that week, 460 in all52%
  4. Sac CountyBest late March · 33 checklists that week, 1,085 in all47%
  5. Union CountyBest mid March · 20 checklists that week, 1,133 in all45%
  6. Shelby CountyBest late March · 11 checklists that week, 354 in all45%

Best spots

Share of checklists at the peak
  1. Goose Lake PondJohnson County, best late March · 43 checklists that week, 404 in all90%
  2. John Deere MarshDubuque County, best mid March · 43 checklists that week, 1,952 in all80%
  3. Nahant MarshScott County, best mid March · 36 checklists that week, 838 in all70%
  4. Lake Macbride State ParkJohnson County, best late March · 39 checklists that week, 890 in all70%
  5. Paul Errington Marsh Waterfowl Production AreaPolk County, best mid March · 35 checklists that week, 512 in all69%
  6. Hendrickson Marsh Wildlife Management AreaStory County, best early April · 21 checklists that week, 556 in all68%

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

Best time of day

In Iowa, the Bufflehead is most often listed on checklists started between 4 and 6 pm (4.7% of those checklists).

0%2%4%6%12 am: too few checklists (96) to judge1 am: too few checklists (99) to judge2 am: too few checklists (67) to judge3 am: too few checklists (82) to judge4 am: too few checklists (201) to judge5 am: too few checklists (1888) to judge6 am: 1.8% of 11313 checklists7 am: 3.2% of 25717 checklists8 am: 3.6% of 29755 checklists9 am: 4.1% of 28897 checklists10 am: 4.3% of 26343 checklists11 am: 4.3% of 21210 checklists12 pm: 4.5% of 17662 checklists1 pm: 4.4% of 16595 checklists2 pm: 4.6% of 16405 checklists3 pm: 4.3% of 17030 checklists4 pm: 4.7% of 17378 checklists5 pm: 4.8% of 14251 checklists6 pm: 3.8% of 10349 checklists7 pm: 1.9% of 6233 checklists8 pm: too few checklists (2002) to judge9 pm: too few checklists (392) to judge10 pm: too few checklists (186) to judge11 pm: too few checklists (87) 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
January0.8%0.5%0.2%0.3%
February0.5%0.7%1.6%5.0%
March11%15%20%21%
April18%12%8.4%3.7%
May1.0%0.3%0.2%0.1%
June0%0.1%0%0%
July0.1%0.1%0%0%
August0%0%0%0%
September0%0%0%0.1%
October0.1%0.3%0.8%3.9%
November5.7%11%9.8%9.0%
December6.6%4.3%2.6%1.1%

Neighboring states

  • Missouri: arrives early November, 13 weeks earlier than Iowa
  • Wisconsin: arrives the second week of October, 16 weeks earlier than Iowa
  • Minnesota: arrives early March, 3 weeks later than Iowa
  • Illinois: arrives late October, 14 weeks earlier than Iowa

Common questions

When do Buffleheads arrive in Iowa?
Buffleheads are winter birds in Iowa: the first arrive in the second week of February, they are common by late February, peak in late March (19% of checklists), and most are gone by late April.
When do Buffleheads leave Iowa?
Most Buffleheads have left Iowa by late April, when reports fall below half their usual rate. Stragglers are still reported until early May.
When is the best time to see a Bufflehead in Iowa?
The Bufflehead is reported most often in late March, on about 19% of Iowa checklists.
Where in Iowa are Buffleheads seen most often?
By county, Worth County, Hancock County, and Palo Alto County have the highest peak reporting rates for the Bufflehead (counties with at least 200 checklists).