WhenToBird

Spizelloides arborea · Passerellidae

When Do American Tree Sparrows Arrive in Iowa?

Adult American Tree Sparrow
Photo: Michael, CC BY 4.0 via iNaturalist

American Tree Sparrows are winter birds in Iowa: the first arrive in mid October, they are common by early November, peak in the second week of December (22% of checklists), and most are gone by early April.

When to look

First arrivalsOct 15-21mid October
Common byNov 1-7early November
PeakDec 8-14the second week of December
Most gone byApr 1-7early April

Best: the second week of December. First arrivals mid October; most are gone by early April. Peak: on about 22% of Iowa checklists.

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

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

0%10%20%30%Jan 1-7: 21% of 5551 checklistsJan 8-14: 19% of 3498 checklistsJan 15-21: 20% of 3803 checklistsJan 22-31: 21% of 4807 checklistsFeb 1-7: 20% of 3613 checklistsFeb 8-14: 21% of 4173 checklistsFeb 15-21: 17% of 5796 checklistsFeb 22-28: 19% of 4394 checklistsMar 1-7: 17% of 5295 checklistsMar 8-14: 20% of 5679 checklistsMar 15-21: 17% of 5418 checklistsMar 22-31: 15% of 8613 checklistsApr 1-7: 12% of 6970 checklistsApr 8-14: 6.0% of 7511 checklistsApr 15-21: 3.2% of 8321 checklistsApr 22-30: 0.5% of 11976 checklistsMay 1-7: 0% of 11725 checklistsMay 8-14: 0.1% of 12626 checklistsMay 15-21: 0% of 9372 checklistsMay 22-31: 0% of 10330 checklistsJun 1-7: 0% of 5472 checklistsJun 8-14: 0% of 4568 checklistsJun 15-21: 0% of 3870 checklistsJun 22-30: 0% of 4780 checklistsJul 1-7: 0% of 4201 checklistsJul 8-14: 0% 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: 0.4% of 4791 checklistsOct 15-21: 2.1% of 4429 checklistsOct 22-31: 5.7% of 5633 checklistsNov 1-7: 16% of 4090 checklistsNov 8-14: 21% of 3416 checklistsNov 15-21: 21% of 3398 checklistsNov 22-30: 21% of 4679 checklistsDec 1-7: 21% of 3442 checklistsDec 8-14: 21% of 3322 checklistsDec 15-21: 23% of 4619 checklistsDec 22-31: 20% 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.

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Where in Iowa

Best counties

Share of checklists at the peak
  1. Ringgold CountyBest mid January · 17 checklists that week, 1,141 in all69%
  2. Louisa CountyBest late December · 31 checklists that week, 1,639 in all64%
  3. Grundy CountyBest the second week of November · 17 checklists that week, 647 in all60%
  4. Union CountyBest early January · 36 checklists that week, 1,133 in all57%
  5. Tama CountyBest early January · 11 checklists that week, 973 in all57%
  6. Poweshiek CountyBest mid November · 11 checklists that week, 1,402 in all55%

Best spots

Share of checklists at the peak
  1. John Deere MarshDubuque County, best late January · 26 checklists that week, 1,952 in all86%
  2. Big Creek Wildlife Management AreaPolk County, best early January · 22 checklists that week, 500 in all82%
  3. Ada Hayden Heritage ParkStory County, best early December · 35 checklists that week, 1,681 in all82%
  4. Tedesco Environmental Learning Corridor (TELC)Story County, best the second week of November · 20 checklists that week, 969 in all82%
  5. Little Storm Lake Wildlife Management AreaBuena Vista County, best late January · 28 checklists that week, 968 in all79%
  6. Cone Marsh Wildlife Management AreaLouisa County, best mid December · 25 checklists that week, 1,002 in all76%

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

Best time of day

In Iowa, the American Tree Sparrow is most often listed on checklists started between 2 and 4 pm (9.0% of those checklists).

0%5%10%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: 2.7% of 11313 checklists7 am: 7.3% of 25717 checklists8 am: 8.3% of 29755 checklists9 am: 8.8% of 28897 checklists10 am: 9.0% of 26343 checklists11 am: 8.7% of 21210 checklists12 pm: 8.3% of 17662 checklists1 pm: 9.0% of 16595 checklists2 pm: 8.8% of 16405 checklists3 pm: 9.1% of 17030 checklists4 pm: 8.2% of 17378 checklists5 pm: 5.1% of 14251 checklists6 pm: 2.7% of 10349 checklists7 pm: 1.4% 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
January21%19%20%21%
February20%21%17%19%
March17%20%17%15%
April12%6.0%3.2%0.5%
May0%0.1%0%0%
June0%0%0%0%
July0%0%0%0%
August0%0%0%0%
September0%0%0%0.1%
October0.1%0.4%2.1%5.7%
November16%21%21%21%
December21%21%23%20%

Neighboring states

  • Missouri: arrives early November, 2 weeks later than Iowa
  • Wisconsin: arrives the second week of October, 1 week earlier than Iowa
  • Minnesota: arrives early October, 2 weeks earlier than Iowa
  • Illinois: arrives mid October, in the same week than Iowa

Common questions

When do American Tree Sparrows arrive in Iowa?
American Tree Sparrows are winter birds in Iowa: the first arrive in mid October, they are common by early November, peak in the second week of December (22% of checklists), and most are gone by early April.
When do American Tree Sparrows leave Iowa?
Most American Tree Sparrows have left Iowa by early April, when reports fall below half their usual rate. Stragglers are still reported until mid April.
When is the best time to see a American Tree Sparrow in Iowa?
The American Tree Sparrow is reported most often in the second week of December, on about 22% of Iowa checklists.
Where in Iowa are American Tree Sparrows seen most often?
By county, Ringgold County, Louisa County, and Grundy County have the highest peak reporting rates for the American Tree Sparrow (counties with at least 200 checklists).