WhenToBird

Falco peregrinus · Falconidae

When Do Peregrine Falcons Arrive in Wyoming?

Adult Peregrine Falcon
Photo: Andrea Poggi, CC BY 4.0 via iNaturalist

Peregrine Falcons arrive in Wyoming in early April, peak in mid August (1.3% of checklists), and most are gone by late September.

When to look

First arrivalsApr 1-7early April
Common byApr 1-7early April
PeakAug 15-21mid August
Most gone bySep 22-30late September

Best: mid August. First arrivals early April; most are gone by late September. Peak: on about 1.3% of Wyoming checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Maruncommon
  4. Aprcommon
  5. Maycommon
  6. Juncommon
  7. Julpeak season
  8. Augpeak season
  9. Seppeak season
  10. Octuncommon
  11. Novrare
  12. Decrare

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

0%0.5%1%1.5%Jan 1-7: 0.1% of 2543 checklistsJan 8-14: 0% of 2114 checklistsJan 15-21: 0% of 1984 checklistsJan 22-31: 0.1% of 2605 checklistsFeb 1-7: 0% of 1940 checklistsFeb 8-14: 0.1% of 1954 checklistsFeb 15-21: 0.1% of 2575 checklistsFeb 22-28: 0% of 1932 checklistsMar 1-7: 0% of 2486 checklistsMar 8-14: 0.1% of 2535 checklistsMar 15-21: 0.2% of 2726 checklistsMar 22-31: 0.3% of 4349 checklistsApr 1-7: 0.6% of 3300 checklistsApr 8-14: 0.6% of 3500 checklistsApr 15-21: 0.8% of 3701 checklistsApr 22-30: 0.9% of 5887 checklistsMay 1-7: 1.0% of 5341 checklistsMay 8-14: 0.9% of 6910 checklistsMay 15-21: 0.8% of 6884 checklistsMay 22-31: 0.8% of 10652 checklistsJun 1-7: 0.7% of 6807 checklistsJun 8-14: 0.9% of 6714 checklistsJun 15-21: 0.6% of 6708 checklistsJun 22-30: 1.1% of 8160 checklistsJul 1-7: 0.7% of 5755 checklistsJul 8-14: 0.9% of 5379 checklistsJul 15-21: 1.1% of 5299 checklistsJul 22-31: 1.3% of 6830 checklistsAug 1-7: 1.0% of 4581 checklistsAug 8-14: 1.3% of 4625 checklistsAug 15-21: 1.3% of 4466 checklistsAug 22-31: 1.2% of 6562 checklistsSep 1-7: 1.1% of 4543 checklistsSep 8-14: 0.9% of 4652 checklistsSep 15-21: 0.9% of 4186 checklistsSep 22-30: 0.6% of 5301 checklistsOct 1-7: 0.1% of 3248 checklistsOct 8-14: 0.1% of 3010 checklistsOct 15-21: 0.1% of 2624 checklistsOct 22-31: 0.1% of 3170 checklistsNov 1-7: 0.1% of 2110 checklistsNov 8-14: 0% of 2153 checklistsNov 15-21: 0.2% of 1971 checklistsNov 22-30: 0.1% of 2136 checklistsDec 1-7: 0% of 1646 checklistsDec 8-14: 0.1% of 1609 checklistsDec 15-21: 0.1% of 1954 checklistsDec 22-31: 0% of 2392 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 Wyoming 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 Wyoming

Best counties

Share of checklists at the peak
  1. Crook CountyBest early August · 91 checklists that week, 3,915 in all15%
  2. Big Horn CountyBest late January · 12 checklists that week, 2,023 in all3.7%
  3. Washakie CountyBest early July · 150 checklists that week, 6,033 in all3.4%
  4. Goshen CountyBest late April · 45 checklists that week, 1,920 in all2.4%
  5. Platte CountyBest late July · 57 checklists that week, 1,645 in all2.3%
  6. Lincoln CountyBest early September · 110 checklists that week, 3,169 in all2.2%

Best spots

Share of checklists at the peak
  1. Devils Tower National MonumentCrook County, best early August · 28 checklists that week, 954 in all35%
  2. The SinksFremont County, best late May · 25 checklists that week, 338 in all14%
  3. South Park Wildlife Habitat Management AreaTeton County, best late August · 29 checklists that week, 756 in all13%
  4. Hutton Lake National Wildlife RefugeAlbany County, best late August · 46 checklists that week, 936 in all8.0%
  5. Yellowstone National Park (east)Park County, best late June · 31 checklists that week, 439 in all6.2%
  6. Yellowstone National Park (Elk Antler Creek)Park County, best the second week of June · 20 checklists that week, 402 in all5.9%

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

Best time of day

In Wyoming, the Peregrine Falcon is most often listed on checklists started between 9 and 11 am (0.8% of those checklists).

0%0.5%1%12 am: too few checklists (59) to judge1 am: too few checklists (76) to judge2 am: too few checklists (86) to judge3 am: too few checklists (79) to judge4 am: too few checklists (326) to judge5 am: too few checklists (2271) to judge6 am: 0.8% of 8808 checklists7 am: 0.6% of 18458 checklists8 am: 0.7% of 22143 checklists9 am: 0.9% of 21499 checklists10 am: 0.8% of 19425 checklists11 am: 0.7% of 16017 checklists12 pm: 0.6% of 13868 checklists1 pm: 0.5% of 12984 checklists2 pm: 0.6% of 12605 checklists3 pm: 0.6% of 11821 checklists4 pm: 0.7% of 10571 checklists5 pm: 0.7% of 8746 checklists6 pm: 0.7% of 6707 checklists7 pm: 0.6% of 4890 checklists8 pm: too few checklists (2323) to judge9 pm: too few checklists (554) to judge10 pm: too few checklists (134) to judge11 pm: too few checklists (59) 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
January0.1%0%0%0.1%
February0%0.1%0.1%0%
March0%0.1%0.2%0.3%
April0.6%0.6%0.8%0.9%
May1.0%0.9%0.8%0.8%
June0.7%0.9%0.6%1.1%
July0.7%0.9%1.1%1.3%
August1.0%1.3%1.3%1.2%
September1.1%0.9%0.9%0.6%
October0.1%0.1%0.1%0.1%
November0.1%0%0.2%0.1%
December0%0.1%0.1%0%

Neighboring states

  • Colorado: arrives mid March, 2 weeks earlier than Wyoming
  • Utah: arrives late February, 5 weeks earlier than Wyoming
  • Montana: arrives late March, 1 week earlier than Wyoming
  • Idaho: arrives late January, 9 weeks earlier than Wyoming

Common questions

When do Peregrine Falcons arrive in Wyoming?
Peregrine Falcons arrive in Wyoming in early April, peak in mid August (1.3% of checklists), and most are gone by late September.
When do Peregrine Falcons leave Wyoming?
Most Peregrine Falcons have left Wyoming by late September, when reports fall below half their usual rate.
When is the best time to see a Peregrine Falcon in Wyoming?
The Peregrine Falcon is reported most often in mid August, on about 1.3% of Wyoming checklists.
Where in Wyoming are Peregrine Falcons seen most often?
By county, Crook County, Big Horn County, and Washakie County have the highest peak reporting rates for the Peregrine Falcon (counties with at least 200 checklists).