WhenToBird

Stelgidopteryx serripennis · Hirundinidae

When Do Northern Rough-winged Swallows Arrive in Arizona?

Adult Northern Rough-winged Swallow
Photo: Peter Chen 2.0, CC BY 4.0 via iNaturalist

Northern Rough-winged Swallows are in Arizona all year, but most are here in spring: numbers build from mid February, peak in mid March (16% of checklists), and fall back by mid June. In the quietest week (the second week of November) they are still on about 3.6% of checklists.

When to look

Numbers buildFeb 15-21mid February
PeakMar 15-21mid March
Fall back byJun 15-21mid June
FewestNov 8-14the second week of November

Best: mid March. Here all year; numbers build from mid February and fall back by mid June. Peak: on about 16% of Arizona checklists.

  1. Januncommon
  2. Febpeak season
  3. Marpeak season
  4. Aprpeak season
  5. Maypeak season
  6. Juncommon
  7. Julcommon
  8. Auguncommon
  9. Sepuncommon
  10. Octuncommon
  11. Novuncommon
  12. Decuncommon

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

0%5%10%15%20%Jan 1-7: 4.4% of 34758 checklistsJan 8-14: 4.0% of 29835 checklistsJan 15-21: 4.4% of 29279 checklistsJan 22-31: 4.9% of 39716 checklistsFeb 1-7: 6.6% of 27299 checklistsFeb 8-14: 8.6% of 28703 checklistsFeb 15-21: 9.5% of 35357 checklistsFeb 22-28: 13% of 29889 checklistsMar 1-7: 14% of 29932 checklistsMar 8-14: 15% of 32982 checklistsMar 15-21: 16% of 34731 checklistsMar 22-31: 16% of 50213 checklistsApr 1-7: 15% of 35788 checklistsApr 8-14: 14% of 38087 checklistsApr 15-21: 14% of 41520 checklistsApr 22-30: 15% of 55218 checklistsMay 1-7: 14% of 39688 checklistsMay 8-14: 13% of 39398 checklistsMay 15-21: 13% of 29562 checklistsMay 22-31: 11% of 36774 checklistsJun 1-7: 11% of 21313 checklistsJun 8-14: 11% of 19129 checklistsJun 15-21: 11% of 17922 checklistsJun 22-30: 9.4% of 21188 checklistsJul 1-7: 6.8% of 17325 checklistsJul 8-14: 5.6% of 16463 checklistsJul 15-21: 4.7% of 18642 checklistsJul 22-31: 4.4% of 31215 checklistsAug 1-7: 4.2% of 28163 checklistsAug 8-14: 4.2% of 31329 checklistsAug 15-21: 5.7% of 23878 checklistsAug 22-31: 5.5% of 28508 checklistsSep 1-7: 6.0% of 20878 checklistsSep 8-14: 6.6% of 19671 checklistsSep 15-21: 5.6% of 19859 checklistsSep 22-30: 5.7% of 25179 checklistsOct 1-7: 6.2% of 19420 checklistsOct 8-14: 5.3% of 21925 checklistsOct 15-21: 4.9% of 20995 checklistsOct 22-31: 4.4% of 29258 checklistsNov 1-7: 3.6% of 21269 checklistsNov 8-14: 3.4% of 22753 checklistsNov 15-21: 3.8% of 21982 checklistsNov 22-30: 3.9% of 29475 checklistsDec 1-7: 4.1% of 20810 checklistsDec 8-14: 3.7% of 22229 checklistsDec 15-21: 3.2% of 25148 checklistsDec 22-31: 3.9% 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. Maricopa CountyBest late May · 5405 checklists that week, 269,896 in all31%
  2. Yavapai CountyBest mid April · 2511 checklists that week, 83,606 in all27%
  3. Yuma CountyBest mid March · 378 checklists that week, 14,687 in all25%
  4. Greenlee CountyBest late March · 62 checklists that week, 2,745 in all18%
  5. Pima CountyBest mid March · 11365 checklists that week, 437,722 in all18%
  6. La Paz CountyBest late May · 131 checklists that week, 7,279 in all17%

Best spots

Share of checklists at the peak
  1. Los MorterosPima County, best mid June · 118 checklists that week, 7,146 in all92%
  2. Arthur Pack Regional ParkPima County, best the second week of June · 42 checklists that week, 4,553 in all87%

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

Best time of day

In Arizona, the Northern Rough-winged Swallow is most often listed on checklists started between 5 and 7 am (14% of those checklists).

0%5%10%15%20%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: 15% of 38350 checklists6 am: 14% of 118786 checklists7 am: 11% of 183415 checklists8 am: 9.3% of 187346 checklists9 am: 8.1% of 151342 checklists10 am: 7.3% of 124522 checklists11 am: 6.6% of 97088 checklists12 pm: 6.1% of 78110 checklists1 pm: 6.2% of 73059 checklists2 pm: 6.6% of 68912 checklists3 pm: 7.3% of 68060 checklists4 pm: 7.3% of 69387 checklists5 pm: 8.2% of 52951 checklists6 pm: 7.6% 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
January4.4%4.0%4.4%4.9%
February6.6%8.6%9.5%13%
March14%15%16%16%
April15%14%14%15%
May14%13%13%11%
June11%11%11%9.4%
July6.8%5.6%4.7%4.4%
August4.2%4.2%5.7%5.5%
September6.0%6.6%5.6%5.7%
October6.2%5.3%4.9%4.4%
November3.6%3.4%3.8%3.9%
December4.1%3.7%3.2%3.9%

Neighboring states

  • New Mexico: arrives late February, 1 week later than Arizona
  • Nevada: arrives the second week of March, 3 weeks later than Arizona
  • Utah: arrives the second week of March, 3 weeks later than Arizona
  • California: arrives the second week of February, 1 week earlier than Arizona

Common questions

When do Northern Rough-winged Swallows arrive in Arizona?
Northern Rough-winged Swallows are in Arizona all year, but most are here in spring: numbers build from mid February, peak in mid March (16% of checklists), and fall back by mid June. In the quietest week (the second week of November) they are still on about 3.6% of checklists.
When do Northern Rough-winged Swallows leave Arizona?
Northern Rough-winged Swallows never fully leave Arizona: numbers fall back below half their usual rate by mid June, but some are still reported in every week, about 3.6% of checklists at the low.
When is the best time to see a Northern Rough-winged Swallow in Arizona?
The Northern Rough-winged Swallow is reported most often in mid March, on about 16% of Arizona checklists.
Where in Arizona are Northern Rough-winged Swallows seen most often?
By county, Maricopa County, Yavapai County, and Yuma County have the highest peak reporting rates for the Northern Rough-winged Swallow (counties with at least 200 checklists).