WhenToBird

Spizelloides arborea · Passerellidae

When Do American Tree Sparrows Arrive in Montana?

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

American Tree Sparrows are winter birds in Montana: the first arrive in early October, they are common by the second week of October, peak in early November (10% of checklists), and most are gone by late March.

When to look

First arrivalsOct 1-7early October
Common byOct 8-14the second week of October
PeakNov 1-7early November
Most gone byMar 22-31late March

Best: early November. First arrivals early October; most are gone by late March. Peak: on about 10% of Montana checklists.

  1. Jancommon
  2. Febcommon
  3. Marcommon
  4. Apruncommon
  5. Maynot usually seen
  6. Junnot usually seen
  7. Julnot usually seen
  8. Augnot usually seen
  9. Sepnot usually seen
  10. Octpeak season
  11. Novpeak season
  12. Deccommon

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

0%5%10%15%Jan 1-7: 6.1% of 7987 checklistsJan 8-14: 5.6% of 5561 checklistsJan 15-21: 5.5% of 5613 checklistsJan 22-31: 4.7% of 7881 checklistsFeb 1-7: 5.1% of 5018 checklistsFeb 8-14: 6.1% of 5598 checklistsFeb 15-21: 5.8% of 7247 checklistsFeb 22-28: 4.9% of 5531 checklistsMar 1-7: 4.8% of 6110 checklistsMar 8-14: 4.5% of 6623 checklistsMar 15-21: 4.8% of 7687 checklistsMar 22-31: 3.2% of 11095 checklistsApr 1-7: 2.2% of 7774 checklistsApr 8-14: 1.1% of 8785 checklistsApr 15-21: 0.5% of 9684 checklistsApr 22-30: 0.1% of 13805 checklistsMay 1-7: 0.1% of 11847 checklistsMay 8-14: 0% of 13547 checklistsMay 15-21: 0% of 13019 checklistsMay 22-31: 0% of 20456 checklistsJun 1-7: 0% of 12993 checklistsJun 8-14: 0% of 11594 checklistsJun 15-21: 0% of 11159 checklistsJun 22-30: 0% of 13786 checklistsJul 1-7: 0% of 9584 checklistsJul 8-14: 0% of 9078 checklistsJul 15-21: 0% of 7905 checklistsJul 22-31: 0% of 10906 checklistsAug 1-7: 0% of 7335 checklistsAug 8-14: 0% of 6868 checklistsAug 15-21: 0% of 6866 checklistsAug 22-31: 0% of 10076 checklistsSep 1-7: 0% of 7670 checklistsSep 8-14: 0.1% of 7490 checklistsSep 15-21: 0% of 6804 checklistsSep 22-30: 0.2% of 8016 checklistsOct 1-7: 0.8% of 5996 checklistsOct 8-14: 3.5% of 6156 checklistsOct 15-21: 7.8% of 5742 checklistsOct 22-31: 11% of 7790 checklistsNov 1-7: 10% of 5353 checklistsNov 8-14: 9.6% of 5475 checklistsNov 15-21: 6.3% of 4603 checklistsNov 22-30: 6.3% of 6067 checklistsDec 1-7: 5.8% of 4362 checklistsDec 8-14: 4.7% of 4467 checklistsDec 15-21: 5.5% of 5328 checklistsDec 22-31: 6.1% of 6672 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 Montana 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 Montana

Best counties

Share of checklists at the peak
  1. Richland CountyBest mid October · 19 checklists that week, 673 in all58%
  2. Big Horn CountyBest early November · 27 checklists that week, 1,279 in all41%
  3. Hill CountyBest the second week of October · 25 checklists that week, 988 in all41%
  4. Phillips CountyBest late October · 20 checklists that week, 4,818 in all38%
  5. Chouteau CountyBest mid October · 10 checklists that week, 954 in all32%
  6. Sheridan CountyBest mid March · 11 checklists that week, 2,316 in all31%

Best spots

Share of checklists at the peak
  1. Willow CreekGallatin County, best mid February · 21 checklists that week, 911 in all71%
  2. Lee Metcalf National Wildlife Refuge (northeast)Ravalli County, best the second week of November · 30 checklists that week, 838 in all66%
  3. Drouillard Fishing Access SiteGallatin County, best early January · 21 checklists that week, 273 in all53%
  4. Helena Valley Reservoir Fishing Access Site (Helena Valley Regulating Reservoir)Lewis and Clark County, best the second week of November · 29 checklists that week, 484 in all44%

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

Best time of day

In Montana, the American Tree Sparrow is most often listed on checklists started between 9 and 11 am (2.8% of those checklists).

0%1%2%3%12 am: too few checklists (183) to judge1 am: too few checklists (169) to judge2 am: too few checklists (163) to judge3 am: too few checklists (212) to judge4 am: too few checklists (503) to judge5 am: too few checklists (4022) to judge6 am: 0.6% of 12719 checklists7 am: 1.8% of 31202 checklists8 am: 2.5% of 47646 checklists9 am: 2.8% of 44624 checklists10 am: 2.8% of 40704 checklists11 am: 2.8% of 33825 checklists12 pm: 2.7% of 29407 checklists1 pm: 2.5% of 27959 checklists2 pm: 2.4% of 26928 checklists3 pm: 2.7% of 25313 checklists4 pm: 2.4% of 22151 checklists5 pm: 1.5% of 16884 checklists6 pm: 0.7% of 13780 checklists7 pm: 0.2% of 9926 checklists8 pm: too few checklists (5765) to judge9 pm: too few checklists (2099) to judge10 pm: too few checklists (595) to judge11 pm: too few checklists (230) 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
January6.1%5.6%5.5%4.7%
February5.1%6.1%5.8%4.9%
March4.8%4.5%4.8%3.2%
April2.2%1.1%0.5%0.1%
May0.1%0%0%0%
June0%0%0%0%
July0%0%0%0%
August0%0%0%0%
September0%0.1%0%0.2%
October0.8%3.5%7.8%11%
November10%9.6%6.3%6.3%
December5.8%4.7%5.5%6.1%

Neighboring states

  • Idaho: arrives late October, 3 weeks later than Montana
  • Wyoming: arrives mid October, 2 weeks later than Montana
  • Utah: arrives early November, 4 weeks later than Montana
  • Colorado: arrives mid October, 2 weeks later than Montana

Common questions

When do American Tree Sparrows arrive in Montana?
American Tree Sparrows are winter birds in Montana: the first arrive in early October, they are common by the second week of October, peak in early November (10% of checklists), and most are gone by late March.
When do American Tree Sparrows leave Montana?
Most American Tree Sparrows have left Montana by late March, when reports fall below half their usual rate. Stragglers are still reported until the second week of April.
When is the best time to see a American Tree Sparrow in Montana?
The American Tree Sparrow is reported most often in early November, on about 10% of Montana checklists.
Where in Montana are American Tree Sparrows seen most often?
By county, Richland County, Big Horn County, and Hill County have the highest peak reporting rates for the American Tree Sparrow (counties with at least 200 checklists).