WhenToBird

Vireo cassinii · Vireonidae

When Do Cassin's Vireos Arrive in Nevada?

Adult Cassin's Vireo
Photo: David Anderson, CC BY 4.0 via iNaturalist

Cassin's Vireos arrive in Nevada in the second week of April, peak in the second week of May (4.3% of checklists), and most are gone by mid July.

When to look

First arrivalsApr 8-14the second week of April
Common byApr 8-14the second week of April
PeakMay 8-14the second week of May
Most gone byJul 15-21mid July

Best: the second week of May. First arrivals the second week of April; most are gone by mid July. Peak: on about 4.3% of Nevada checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Marrare
  4. Aprpeak season
  5. Maypeak season
  6. Juncommon
  7. Julcommon
  8. Augcommon
  9. Sepcommon
  10. Octuncommon
  11. Novnot usually seen
  12. Decnot usually seen

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

0%2%4%6%Jan 1-7: 0.1% of 5121 checklistsJan 8-14: 0% of 3908 checklistsJan 15-21: 0% of 4000 checklistsJan 22-31: 0% of 4991 checklistsFeb 1-7: 0% of 3377 checklistsFeb 8-14: 0% of 3747 checklistsFeb 15-21: 0% of 4852 checklistsFeb 22-28: 0% of 3712 checklistsMar 1-7: 0% of 3745 checklistsMar 8-14: 0% of 3763 checklistsMar 15-21: 0% of 4188 checklistsMar 22-31: 0.2% of 6027 checklistsApr 1-7: 0.8% of 4679 checklistsApr 8-14: 1.8% of 4609 checklistsApr 15-21: 3.0% of 4709 checklistsApr 22-30: 3.3% of 6984 checklistsMay 1-7: 4.5% of 5702 checklistsMay 8-14: 4.4% of 5928 checklistsMay 15-21: 4.0% of 5353 checklistsMay 22-31: 2.9% of 7352 checklistsJun 1-7: 2.7% of 4360 checklistsJun 8-14: 1.9% of 4183 checklistsJun 15-21: 1.9% of 3751 checklistsJun 22-30: 2.4% of 4126 checklistsJul 1-7: 2.0% of 3231 checklistsJul 8-14: 1.2% of 3024 checklistsJul 15-21: 1.2% of 2967 checklistsJul 22-31: 0.8% of 4212 checklistsAug 1-7: 1.0% of 2828 checklistsAug 8-14: 1.4% of 3036 checklistsAug 15-21: 1.7% of 3076 checklistsAug 22-31: 1.8% of 4345 checklistsSep 1-7: 2.3% of 3369 checklistsSep 8-14: 1.9% of 3728 checklistsSep 15-21: 1.8% of 3535 checklistsSep 22-30: 1.0% of 5028 checklistsOct 1-7: 0.7% of 3976 checklistsOct 8-14: 0.7% of 3781 checklistsOct 15-21: 0.6% of 3577 checklistsOct 22-31: 0.2% of 4986 checklistsNov 1-7: 0.1% of 3592 checklistsNov 8-14: 0.1% of 3685 checklistsNov 15-21: 0% of 3399 checklistsNov 22-30: 0% of 4544 checklistsDec 1-7: 0.1% of 3162 checklistsDec 8-14: 0% of 3191 checklistsDec 15-21: 0% of 3615 checklistsDec 22-31: 0% of 5101 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 Nevada 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 Nevada

Best counties

Share of checklists at the peak
  1. Douglas CountyBest the second week of July · 119 checklists that week, 7,476 in all9.5%
  2. Carson CityBest early July · 140 checklists that week, 6,992 in all8.1%
  3. Esmeralda CountyBest the second week of May · 130 checklists that week, 2,275 in all7.3%
  4. Storey CountyBest late August · 44 checklists that week, 1,593 in all6.7%
  5. Washoe CountyBest the second week of May · 1623 checklists that week, 53,497 in all6.5%
  6. Clark CountyBest late April · 2801 checklists that week, 80,458 in all5.9%

Best spots

Share of checklists at the peak
  1. Toiyabe National ForestWashoe County, best the second week of June · 27 checklists that week, 877 in all59%
  2. Spooner LakeDouglas County, best early June · 24 checklists that week, 634 in all33%
  3. Spring Mountains National Recreation AreaClark County, best late August · 33 checklists that week, 748 in all30%
  4. Rancho San Rafael Regional ParkWashoe County, best the second week of May · 110 checklists that week, 2,403 in all23%
  5. Corn Creek SpringsClark County, best mid April · 201 checklists that week, 6,865 in all22%

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

Best time of day

In Nevada, the Cassin's Vireo is most often listed on checklists started between 5 and 7 am (2.1% of those checklists).

0%1%2%3%12 am: too few checklists (114) to judge1 am: too few checklists (99) to judge2 am: too few checklists (71) to judge3 am: too few checklists (108) to judge4 am: too few checklists (459) to judge5 am: 2.2% of 4313 checklists6 am: 2.1% of 17070 checklists7 am: 2.0% of 27389 checklists8 am: 1.9% of 24858 checklists9 am: 1.2% of 22012 checklists10 am: 1.1% of 19284 checklists11 am: 0.9% of 15592 checklists12 pm: 0.7% of 12432 checklists1 pm: 0.7% of 11386 checklists2 pm: 0.6% of 11262 checklists3 pm: 0.6% of 10721 checklists4 pm: 0.7% of 9090 checklists5 pm: 0.7% of 6397 checklists6 pm: 0.6% of 5012 checklists7 pm: too few checklists (3026) to judge8 pm: too few checklists (905) to judge9 pm: too few checklists (271) to judge10 pm: too few checklists (164) to judge11 pm: too few checklists (120) 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%
February0%0%0%0%
March0%0%0%0.2%
April0.8%1.8%3.0%3.3%
May4.5%4.4%4.0%2.9%
June2.7%1.9%1.9%2.4%
July2.0%1.2%1.2%0.8%
August1.0%1.4%1.7%1.8%
September2.3%1.9%1.8%1.0%
October0.7%0.7%0.6%0.2%
November0.1%0.1%0%0%
December0.1%0%0%0%

Neighboring states

  • California: arrives the second week of April, in the same week than Nevada
  • Utah: arrives late August, 18 weeks later than Nevada
  • Idaho: arrives late April, 2 weeks later than Nevada
  • Arizona: arrives early March, 5 weeks earlier than Nevada

Common questions

When do Cassin's Vireos arrive in Nevada?
Cassin's Vireos arrive in Nevada in the second week of April, peak in the second week of May (4.3% of checklists), and most are gone by mid July.
When do Cassin's Vireos leave Nevada?
Most Cassin's Vireos have left Nevada by mid July, when reports fall below half their usual rate.
When is the best time to see a Cassin's Vireo in Nevada?
The Cassin's Vireo is reported most often in the second week of May, on about 4.3% of Nevada checklists.
Where in Nevada are Cassin's Vireos seen most often?
By county, Douglas County, Carson City, and Esmeralda County have the highest peak reporting rates for the Cassin's Vireo (counties with at least 200 checklists).