WhenToBird

Falco columbarius · Falconidae

When Do Merlins Arrive in Arizona?

Adult female Merlin
Photo: Cricket Raspet, CC BY 4.0 via iNaturalist

Merlins are winter birds in Arizona: they arrive in late September, peak in the second week of November (1.4% of checklists), and most are gone by mid March.

When to look

First arrivalsSep 22-30late September
Common bySep 22-30late September
PeakNov 8-14the second week of November
Most gone byMar 15-21mid March

Best: the second week of November. First arrivals late September; most are gone by mid March. Peak: on about 1.4% of Arizona checklists.

  1. Jancommon
  2. Febcommon
  3. Marcommon
  4. Apruncommon
  5. Maynot usually seen
  6. Junnot usually seen
  7. Julnot usually seen
  8. Augnot usually seen
  9. Sepcommon
  10. Octpeak season
  11. Novpeak season
  12. Decpeak season

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

0%0.5%1%1.5%Jan 1-7: 0.9% of 34758 checklistsJan 8-14: 1.0% of 29835 checklistsJan 15-21: 1.0% of 29279 checklistsJan 22-31: 0.9% of 39716 checklistsFeb 1-7: 0.8% of 27299 checklistsFeb 8-14: 0.7% of 28703 checklistsFeb 15-21: 0.5% of 35357 checklistsFeb 22-28: 0.6% of 29889 checklistsMar 1-7: 0.5% of 29932 checklistsMar 8-14: 0.5% of 32982 checklistsMar 15-21: 0.7% of 34731 checklistsMar 22-31: 0.4% of 50213 checklistsApr 1-7: 0.3% of 35788 checklistsApr 8-14: 0.3% of 38087 checklistsApr 15-21: 0.2% of 41520 checklistsApr 22-30: 0.1% of 55218 checklistsMay 1-7: 0.1% of 39688 checklistsMay 8-14: 0.1% of 39398 checklistsMay 15-21: 0% of 29562 checklistsMay 22-31: 0% of 36774 checklistsJun 1-7: 0% of 21313 checklistsJun 8-14: 0% of 19129 checklistsJun 15-21: 0% of 17922 checklistsJun 22-30: 0% of 21188 checklistsJul 1-7: 0% of 17325 checklistsJul 8-14: 0% of 16463 checklistsJul 15-21: 0% of 18642 checklistsJul 22-31: 0.1% of 31215 checklistsAug 1-7: 0.1% of 28163 checklistsAug 8-14: 0% of 31329 checklistsAug 15-21: 0% of 23878 checklistsAug 22-31: 0% of 28508 checklistsSep 1-7: 0.1% of 20878 checklistsSep 8-14: 0.2% of 19671 checklistsSep 15-21: 0.4% of 19859 checklistsSep 22-30: 0.6% of 25179 checklistsOct 1-7: 0.7% of 19420 checklistsOct 8-14: 1.0% of 21925 checklistsOct 15-21: 1.2% of 20995 checklistsOct 22-31: 1.4% of 29258 checklistsNov 1-7: 1.4% of 21269 checklistsNov 8-14: 1.5% of 22753 checklistsNov 15-21: 1.4% of 21982 checklistsNov 22-30: 1.2% of 29475 checklistsDec 1-7: 1.2% of 20810 checklistsDec 8-14: 1.1% of 22229 checklistsDec 15-21: 1.0% of 25148 checklistsDec 22-31: 0.9% 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 late January · 23 checklists that week, 2,745 in all4.0%
  2. Cochise CountyBest early November · 1831 checklists that week, 190,093 in all3.1%
  3. Pinal CountyBest the second week of December · 724 checklists that week, 40,036 in all2.8%
  4. La Paz CountyBest late November · 237 checklists that week, 7,279 in all2.3%
  5. Apache CountyBest the second week of October · 257 checklists that week, 12,931 in all2.2%
  6. Yuma CountyBest late October · 386 checklists that week, 14,687 in all2.2%

Best spots

Share of checklists at the peak
  1. Environmental Operations ParkCochise County, best early November · 23 checklists that week, 1,829 in all36%
  2. Parker Canyon LakeCochise County, best the second week of October · 20 checklists that week, 760 in all24%
  3. San Pedro Riparian National Conservation Area (Spring Creek)Cochise County, best the second week of November · 24 checklists that week, 2,218 in all20%
  4. Buenos Aires National Wildlife RefugePima County, best late November · 39 checklists that week, 1,299 in all20%
  5. Case ParkPima County, best early January · 20 checklists that week, 433 in all17%

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

Best time of day

In Arizona, the Merlin is most often listed on checklists started between 7 and 9 am (0.7% of those checklists).

0%0.5%1%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: 0.1% of 38350 checklists6 am: 0.5% of 118786 checklists7 am: 0.7% of 183415 checklists8 am: 0.7% of 187346 checklists9 am: 0.5% of 151342 checklists10 am: 0.4% of 124522 checklists11 am: 0.4% of 97088 checklists12 pm: 0.4% of 78110 checklists1 pm: 0.4% of 73059 checklists2 pm: 0.5% of 68912 checklists3 pm: 0.6% of 68060 checklists4 pm: 0.5% of 69387 checklists5 pm: 0.3% of 52951 checklists6 pm: 0.1% 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
January0.9%1.0%1.0%0.9%
February0.8%0.7%0.5%0.6%
March0.5%0.5%0.7%0.4%
April0.3%0.3%0.2%0.1%
May0.1%0.1%0%0%
June0%0%0%0%
July0%0%0%0.1%
August0.1%0%0%0%
September0.1%0.2%0.4%0.6%
October0.7%1.0%1.2%1.4%
November1.4%1.5%1.4%1.2%
December1.2%1.1%1.0%0.9%

Neighboring states

  • New Mexico: arrives mid September, 1 week earlier than Arizona
  • Nevada: arrives late September, in the same week than Arizona
  • Utah: arrives the second week of October, 2 weeks later than Arizona
  • California: arrives late September, in the same week than Arizona

Common questions

When do Merlins arrive in Arizona?
Merlins are winter birds in Arizona: they arrive in late September, peak in the second week of November (1.4% of checklists), and most are gone by mid March.
When do Merlins leave Arizona?
Most Merlins have left Arizona by mid March, when reports fall below half their usual rate.
When is the best time to see a Merlin in Arizona?
The Merlin is reported most often in the second week of November, on about 1.4% of Arizona checklists.
Where in Arizona are Merlins seen most often?
By county, Greenlee County, Cochise County, and Pinal County have the highest peak reporting rates for the Merlin (counties with at least 200 checklists).