WhenToBird

Toxostoma curvirostre · Mimidae

When Do Curve-billed Thrashers Arrive in Arizona?

Adult Curve-billed Thrasher
Photo: John Rosford, CC BY 4.0 via iNaturalist

The Curve-billed Thrasher is in Arizona all year. It turns up on about 35% of checklists at its peak (early October) and on 23% in its quietest week (early June).

When to look

PresentAll year
Peak weekOct 1-7early October
Quietest weekJun 1-7early June

Best: early October. Here all year. Peak: on about 35% of Arizona checklists.

  1. Jancommon
  2. Febpeak season
  3. Marpeak season
  4. Aprpeak season
  5. Maycommon
  6. Juncommon
  7. Julcommon
  8. Augpeak season
  9. Seppeak season
  10. Octpeak season
  11. Novpeak season
  12. Decpeak season

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

0%10%20%30%40%Jan 1-7: 24% of 34758 checklistsJan 8-14: 24% of 29835 checklistsJan 15-21: 25% of 29279 checklistsJan 22-31: 26% of 39716 checklistsFeb 1-7: 26% of 27299 checklistsFeb 8-14: 28% of 28703 checklistsFeb 15-21: 30% of 35357 checklistsFeb 22-28: 29% of 29889 checklistsMar 1-7: 29% of 29932 checklistsMar 8-14: 28% of 32982 checklistsMar 15-21: 28% of 34731 checklistsMar 22-31: 28% of 50213 checklistsApr 1-7: 28% of 35788 checklistsApr 8-14: 27% of 38087 checklistsApr 15-21: 26% of 41520 checklistsApr 22-30: 25% of 55218 checklistsMay 1-7: 25% of 39688 checklistsMay 8-14: 25% of 39398 checklistsMay 15-21: 24% of 29562 checklistsMay 22-31: 23% of 36774 checklistsJun 1-7: 24% of 21313 checklistsJun 8-14: 23% of 19129 checklistsJun 15-21: 24% of 17922 checklistsJun 22-30: 26% of 21188 checklistsJul 1-7: 26% of 17325 checklistsJul 8-14: 26% of 16463 checklistsJul 15-21: 26% of 18642 checklistsJul 22-31: 25% of 31215 checklistsAug 1-7: 23% of 28163 checklistsAug 8-14: 24% of 31329 checklistsAug 15-21: 26% of 23878 checklistsAug 22-31: 29% of 28508 checklistsSep 1-7: 31% of 20878 checklistsSep 8-14: 31% of 19671 checklistsSep 15-21: 33% of 19859 checklistsSep 22-30: 34% of 25179 checklistsOct 1-7: 36% of 19420 checklistsOct 8-14: 35% of 21925 checklistsOct 15-21: 34% of 20995 checklistsOct 22-31: 32% of 29258 checklistsNov 1-7: 31% of 21269 checklistsNov 8-14: 28% of 22753 checklistsNov 15-21: 28% of 21982 checklistsNov 22-30: 27% of 29475 checklistsDec 1-7: 28% of 20810 checklistsDec 8-14: 25% of 22229 checklistsDec 15-21: 24% of 25148 checklistsDec 22-31: 26% 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. Maricopa CountyBest mid September · 4189 checklists that week, 269,896 in all63%
  2. Pinal CountyBest the second week of June · 399 checklists that week, 40,036 in all44%
  3. Mohave CountyBest late July · 332 checklists that week, 18,083 in all42%
  4. Pima CountyBest early October · 5735 checklists that week, 437,722 in all42%
  5. Cochise CountyBest the second week of October · 2238 checklists that week, 190,093 in all40%
  6. Graham CountyBest early September · 159 checklists that week, 9,876 in all25%

Best spots

Share of checklists at the peak
  1. Usery Mountain Regional ParkMaricopa County, best early November · 29 checklists that week, 949 in all100%
  2. Phoenix South Mountain ParkMaricopa County, best early September · 27 checklists that week, 1,508 in all99%
  3. Papago ParkMaricopa County, best the second week of July · 44 checklists that week, 5,295 in all97%
  4. Veterans Oasis ParkMaricopa County, best the second week of May · 97 checklists that week, 4,034 in all97%

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

Best time of day

In Arizona, the Curve-billed Thrasher is most often listed on checklists started between 5 and 7 am (42% of those checklists).

0%20%40%60%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: 43% of 38350 checklists6 am: 42% of 118786 checklists7 am: 36% of 183415 checklists8 am: 31% of 187346 checklists9 am: 25% of 151342 checklists10 am: 21% of 124522 checklists11 am: 19% of 97088 checklists12 pm: 18% of 78110 checklists1 pm: 18% of 73059 checklists2 pm: 19% of 68912 checklists3 pm: 21% of 68060 checklists4 pm: 25% of 69387 checklists5 pm: 27% of 52951 checklists6 pm: 27% 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
January24%24%25%26%
February26%28%30%29%
March29%28%28%28%
April28%27%26%25%
May25%25%24%23%
June24%23%24%26%
July26%26%26%25%
August23%24%26%29%
September31%31%33%34%
October36%35%34%32%
November31%28%28%27%
December28%25%24%26%

Neighboring states

  • New Mexico: year-round, peaks the second week of October
  • Texas: year-round, peaks the second week of November

Common questions

When do Curve-billed Thrashers arrive in Arizona?
The Curve-billed Thrasher is in Arizona all year. It turns up on about 35% of checklists at its peak (early October) and on 23% in its quietest week (early June).
When do Curve-billed Thrashers leave Arizona?
The Curve-billed Thrasher does not leave Arizona: it is reported all year, from 23% of checklists in early June to 35% in early October.
When is the best time to see a Curve-billed Thrasher in Arizona?
The Curve-billed Thrasher is reported most often in early October, on about 35% of Arizona checklists.
Where in Arizona are Curve-billed Thrashers seen most often?
By county, Maricopa County, Pinal County, and Mohave County have the highest peak reporting rates for the Curve-billed Thrasher (counties with at least 200 checklists).