WhenToBird

Pooecetes gramineus · Passerellidae

When Do Vesper Sparrows Arrive in Arizona?

Adult Vesper Sparrow
Photo: Dani Alba, CC BY 4.0 via iNaturalist

Vesper Sparrows reach Arizona in late August, are common by early September, peak in late September (7.3% of checklists), and most are gone by the second week of April.

When to look

First arrivalsAug 22-31late August
Common bySep 1-7early September
PeakSep 22-30late September
Most gone byApr 8-14the second week of April

Best: late September. First arrivals late August; most are gone by the second week of April. Peak: on about 7.3% of Arizona checklists.

  1. Jancommon
  2. Febcommon
  3. Marcommon
  4. Aprcommon
  5. Mayrare
  6. Junrare
  7. Julrare
  8. Auguncommon
  9. Seppeak season
  10. Octpeak season
  11. Novcommon
  12. Deccommon

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

0%2%4%6%8%Jan 1-7: 4.7% of 34758 checklistsJan 8-14: 4.7% of 29835 checklistsJan 15-21: 4.9% of 29279 checklistsJan 22-31: 4.5% of 39716 checklistsFeb 1-7: 4.0% of 27299 checklistsFeb 8-14: 3.8% of 28703 checklistsFeb 15-21: 3.5% of 35357 checklistsFeb 22-28: 3.8% of 29889 checklistsMar 1-7: 3.8% of 29932 checklistsMar 8-14: 3.6% of 32982 checklistsMar 15-21: 3.7% of 34731 checklistsMar 22-31: 3.7% of 50213 checklistsApr 1-7: 3.2% of 35788 checklistsApr 8-14: 2.7% of 38087 checklistsApr 15-21: 2.1% of 41520 checklistsApr 22-30: 1.4% of 55218 checklistsMay 1-7: 0.8% of 39688 checklistsMay 8-14: 0.6% of 39398 checklistsMay 15-21: 0.6% of 29562 checklistsMay 22-31: 0.5% of 36774 checklistsJun 1-7: 0.7% of 21313 checklistsJun 8-14: 0.6% of 19129 checklistsJun 15-21: 0.6% of 17922 checklistsJun 22-30: 0.6% of 21188 checklistsJul 1-7: 0.7% of 17325 checklistsJul 8-14: 0.7% of 16463 checklistsJul 15-21: 0.7% of 18642 checklistsJul 22-31: 0.4% of 31215 checklistsAug 1-7: 0.2% of 28163 checklistsAug 8-14: 0.3% of 31329 checklistsAug 15-21: 0.4% of 23878 checklistsAug 22-31: 0.8% of 28508 checklistsSep 1-7: 2.4% of 20878 checklistsSep 8-14: 4.8% of 19671 checklistsSep 15-21: 7.0% of 19859 checklistsSep 22-30: 7.7% of 25179 checklistsOct 1-7: 7.0% of 19420 checklistsOct 8-14: 5.5% of 21925 checklistsOct 15-21: 5.4% of 20995 checklistsOct 22-31: 4.7% of 29258 checklistsNov 1-7: 4.0% of 21269 checklistsNov 8-14: 4.1% of 22753 checklistsNov 15-21: 3.6% of 21982 checklistsNov 22-30: 4.1% of 29475 checklistsDec 1-7: 4.1% of 20810 checklistsDec 8-14: 4.3% of 22229 checklistsDec 15-21: 4.2% of 25148 checklistsDec 22-31: 4.2% of 39567 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 Arizona 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 Arizona

Best counties

Share of checklists at the peak
  1. Greenlee CountyBest early October · 33 checklists that week, 2,745 in all24%
  2. Apache CountyBest mid September · 395 checklists that week, 12,931 in all19%
  3. Cochise CountyBest mid January · 3064 checklists that week, 190,093 in all15%
  4. Coconino CountyBest the second week of September · 2051 checklists that week, 90,870 in all13%
  5. Navajo CountyBest mid September · 377 checklists that week, 18,838 in all12%
  6. Gila CountyBest late September · 307 checklists that week, 14,834 in all11%

Best spots

Share of checklists at the peak
  1. Empire-Cienega Area of Critical Environmental Concern (Smith Canyon)Santa Cruz County, best mid October · 23 checklists that week, 711 in all92%
  2. Empire-Cienega Area of Critical Environmental Concern (southwest 2)Pima County, best late October · 20 checklists that week, 409 in all85%
  3. Domingo TankCoconino County, best late May · 21 checklists that week, 144 in all80%
  4. Smith CanyonSanta Cruz County, best the second week of February · 20 checklists that week, 900 in all71%
  5. Empire-Cienega Area of Critical Environmental Concern (south)Santa Cruz County, best late October · 25 checklists that week, 753 in all71%
  6. Empire-Cienega Area of Critical Environmental Concern (southwest)Pima County, best late January · 23 checklists that week, 835 in all64%

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

Best time of day

In Arizona, the Vesper Sparrow is most often listed on checklists started between 7 and 9 am (3.9% of those checklists).

0%1%2%3%4%12 am: too few checklists (488) to judge1 am: too few checklists (503) to judge2 am: too few checklists (489) to judge3 am: too few checklists (735) to judge4 am: too few checklists (4115) to judge5 am: 1.1% of 38350 checklists6 am: 3.2% of 118786 checklists7 am: 3.9% of 183415 checklists8 am: 3.9% of 187346 checklists9 am: 3.6% of 151342 checklists10 am: 3.2% of 124522 checklists11 am: 2.8% of 97088 checklists12 pm: 2.6% of 78110 checklists1 pm: 2.6% of 73059 checklists2 pm: 2.6% of 68912 checklists3 pm: 2.6% of 68060 checklists4 pm: 2.0% of 69387 checklists5 pm: 1.3% of 52951 checklists6 pm: 0.5% of 31061 checklists7 pm: too few checklists (16076) to judge8 pm: too few checklists (5352) to judge9 pm: too few checklists (2369) to judge10 pm: too few checklists (1100) to judge11 pm: too few checklists (604) 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
January4.7%4.7%4.9%4.5%
February4.0%3.8%3.5%3.8%
March3.8%3.6%3.7%3.7%
April3.2%2.7%2.1%1.4%
May0.8%0.6%0.6%0.5%
June0.7%0.6%0.6%0.6%
July0.7%0.7%0.7%0.4%
August0.2%0.3%0.4%0.8%
September2.4%4.8%7.0%7.7%
October7.0%5.5%5.4%4.7%
November4.0%4.1%3.6%4.1%
December4.1%4.3%4.2%4.2%

Neighboring states

  • New Mexico: arrives early March, 23 weeks earlier than Arizona
  • Nevada: arrives early April, 19 weeks earlier than Arizona
  • Utah: arrives early April, 19 weeks earlier than Arizona
  • Colorado: arrives early April, 19 weeks earlier than Arizona

Common questions

When do Vesper Sparrows arrive in Arizona?
Vesper Sparrows reach Arizona in late August, are common by early September, peak in late September (7.3% of checklists), and most are gone by the second week of April.
When do Vesper Sparrows leave Arizona?
Most Vesper Sparrows have left Arizona by the second week of April, when reports fall below half their usual rate. Stragglers are still reported until late April.
When is the best time to see a Vesper Sparrow in Arizona?
The Vesper Sparrow is reported most often in late September, on about 7.3% of Arizona checklists.
Where in Arizona are Vesper Sparrows seen most often?
By county, Greenlee County, Apache County, and Cochise County have the highest peak reporting rates for the Vesper Sparrow (counties with at least 200 checklists).