WhenToBird

Anser rossii · Anatidae

When Do Ross's Geese Arrive in Montana?

Adult Ross's Goose
Photo: Andrew Cannizzaro, CC BY 4.0 via iNaturalist

Ross's Geese arrive in Montana in the second week of March, peak in the second week of April (1.0% of checklists), and most are gone by the second week of May.

When to look

First arrivalsMar 8-14the second week of March
Common byMar 8-14the second week of March
PeakApr 8-14the second week of April
Most gone byMay 8-14the second week of May

Best: the second week of April. First arrivals the second week of March; most are gone by the second week of May. Peak: on about 1.0% of Montana checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Marpeak season
  4. Aprpeak season
  5. Mayuncommon
  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%0.5%1%1.5%Jan 1-7: 0% of 7987 checklistsJan 8-14: 0% of 5561 checklistsJan 15-21: 0% of 5613 checklistsJan 22-31: 0% of 7881 checklistsFeb 1-7: 0% of 5018 checklistsFeb 8-14: 0% of 5598 checklistsFeb 15-21: 0% of 7247 checklistsFeb 22-28: 0% of 5531 checklistsMar 1-7: 0% of 6110 checklistsMar 8-14: 0.1% of 6623 checklistsMar 15-21: 0.4% of 7687 checklistsMar 22-31: 1.0% of 11095 checklistsApr 1-7: 1.1% of 7774 checklistsApr 8-14: 0.9% of 8785 checklistsApr 15-21: 1.1% of 9684 checklistsApr 22-30: 0.5% of 13805 checklistsMay 1-7: 0.1% of 11847 checklistsMay 8-14: 0.1% of 13547 checklistsMay 15-21: 0% of 13019 checklistsMay 22-31: 0% of 20456 checklistsJun 1-7: 0.1% of 12993 checklistsJun 8-14: 0.1% of 11594 checklistsJun 15-21: 0% of 11159 checklistsJun 22-30: 0% of 13786 checklistsJul 1-7: 0.1% of 9584 checklistsJul 8-14: 0% of 9078 checklistsJul 15-21: 0.1% 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: 0.1% of 10076 checklistsSep 1-7: 0% of 7670 checklistsSep 8-14: 0% of 7490 checklistsSep 15-21: 0% of 6804 checklistsSep 22-30: 0% of 8016 checklistsOct 1-7: 0.1% of 5996 checklistsOct 8-14: 0.2% of 6156 checklistsOct 15-21: 0.2% of 5742 checklistsOct 22-31: 0.2% of 7790 checklistsNov 1-7: 0.7% of 5353 checklistsNov 8-14: 0.7% of 5475 checklistsNov 15-21: 0.4% of 4603 checklistsNov 22-30: 0.4% of 6067 checklistsDec 1-7: 0.1% of 4362 checklistsDec 8-14: 0.1% of 4467 checklistsDec 15-21: 0.1% of 5328 checklistsDec 22-31: 0.1% 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. Teton CountyBest the second week of April · 50 checklists that week, 2,579 in all16%
  2. Daniels CountyBest mid March · 10 checklists that week, 481 in all13%
  3. Sheridan CountyBest mid October · 14 checklists that week, 2,316 in all13%
  4. Valley CountyBest the second week of December · 11 checklists that week, 3,392 in all13%
  5. Powell CountyBest the second week of April · 165 checklists that week, 5,305 in all6.1%
  6. Deer Lodge CountyBest the second week of April · 204 checklists that week, 8,732 in all4.5%

Best spots

Share of checklists at the peak
  1. West Bank ParkCascade County, best the second week of October · 20 checklists that week, 691 in all24%
  2. Pond Number OneTeton County, best late March · 36 checklists that week, 214 in all24%
  3. Freezout Lake Wildlife Management AreaTeton County, best early April · 21 checklists that week, 503 in all20%
  4. Pond Number FiveTeton County, best late March · 37 checklists that week, 167 in all14%
  5. Warm Springs Wildlife Management AreaDeer Lodge County, best the second week of April · 31 checklists that week, 838 in all11%

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

Best time of day

In Montana, the Ross's Goose is most often listed on checklists started between 4 and 6 pm (0.2% of those checklists).

0%0.5%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: 0.1% of 12719 checklists7 am: 0.2% of 31202 checklists8 am: 0.2% of 47646 checklists9 am: 0.2% of 44624 checklists10 am: 0.1% of 40704 checklists11 am: 0.2% of 33825 checklists12 pm: 0.2% of 29407 checklists1 pm: 0.2% of 27959 checklists2 pm: 0.2% of 26928 checklists3 pm: 0.2% of 25313 checklists4 pm: 0.2% of 22151 checklists5 pm: 0.3% of 16884 checklists6 pm: 0.2% of 13780 checklists7 pm: 0.1% 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
January0%0%0%0%
February0%0%0%0%
March0%0.1%0.4%1.0%
April1.1%0.9%1.1%0.5%
May0.1%0.1%0%0%
June0.1%0.1%0%0%
July0.1%0%0.1%0%
August0%0%0%0.1%
September0%0%0%0%
October0.1%0.2%0.2%0.2%
November0.7%0.7%0.4%0.4%
December0.1%0.1%0.1%0.1%

Neighboring states

  • Idaho: arrives the second week of February, 4 weeks earlier than Montana
  • Colorado: arrives early November, 17 weeks earlier than Montana
  • Nevada: arrives mid November, 15 weeks earlier than Montana
  • North Dakota: arrives early March, 1 week earlier than Montana

Common questions

When do Ross's Geese arrive in Montana?
Ross's Geese arrive in Montana in the second week of March, peak in the second week of April (1.0% of checklists), and most are gone by the second week of May.
When do Ross's Geese leave Montana?
Most Ross's Geese have left Montana by the second week of May, when reports fall below half their usual rate.
When is the best time to see a Ross's Goose in Montana?
The Ross's Goose is reported most often in the second week of April, on about 1.0% of Montana checklists.
Where in Montana are Ross's Geese seen most often?
By county, Teton County, Daniels County, and Sheridan County have the highest peak reporting rates for the Ross's Goose (counties with at least 200 checklists).