WhenToBird

Aeronautes saxatalis · Apodidae

When Do White-throated Swifts Arrive in Colorado?

Adult White-throated Swift
Photo: Guillermo Roque, CC BY 4.0 via iNaturalist

White-throated Swifts arrive in Colorado in early April, peak in the second week of June (3.8% of checklists), and most are gone by mid September.

When to look

First arrivalsApr 1-7early April
Common byApr 1-7early April
PeakJun 8-14the second week of June
Most gone bySep 15-21mid September

Best: the second week of June. First arrivals early April; most are gone by mid September. Peak: on about 3.8% of Colorado checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Maruncommon
  4. Aprcommon
  5. Maypeak season
  6. Junpeak season
  7. Julpeak season
  8. Augcommon
  9. Sepuncommon
  10. Octuncommon
  11. Novnot usually seen
  12. Decnot usually seen

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

0%1%2%3%4%Jan 1-7: 0.1% of 32254 checklistsJan 8-14: 0% of 23278 checklistsJan 15-21: 0.1% of 22933 checklistsJan 22-31: 0.1% of 30856 checklistsFeb 1-7: 0% of 21464 checklistsFeb 8-14: 0% of 22910 checklistsFeb 15-21: 0% of 28739 checklistsFeb 22-28: 0% of 21833 checklistsMar 1-7: 0.1% of 23066 checklistsMar 8-14: 0.1% of 23783 checklistsMar 15-21: 0.2% of 24797 checklistsMar 22-31: 0.6% of 38439 checklistsApr 1-7: 1.1% of 31676 checklistsApr 8-14: 2.0% of 35092 checklistsApr 15-21: 2.1% of 36778 checklistsApr 22-30: 2.2% of 50885 checklistsMay 1-7: 2.0% of 44186 checklistsMay 8-14: 2.6% of 49011 checklistsMay 15-21: 2.9% of 40784 checklistsMay 22-31: 3.1% of 53073 checklistsJun 1-7: 3.7% of 32432 checklistsJun 8-14: 3.9% of 29978 checklistsJun 15-21: 3.8% of 29457 checklistsJun 22-30: 3.6% of 36072 checklistsJul 1-7: 3.4% of 28857 checklistsJul 8-14: 2.9% of 27224 checklistsJul 15-21: 2.4% of 27629 checklistsJul 22-31: 2.2% of 37318 checklistsAug 1-7: 1.8% of 25893 checklistsAug 8-14: 1.7% of 24870 checklistsAug 15-21: 1.3% of 24035 checklistsAug 22-31: 1.1% of 35691 checklistsSep 1-7: 1.0% of 27068 checklistsSep 8-14: 1.1% of 26709 checklistsSep 15-21: 1.3% of 26098 checklistsSep 22-30: 1.0% of 31550 checklistsOct 1-7: 0.8% of 24110 checklistsOct 8-14: 0.2% of 23352 checklistsOct 15-21: 0.1% of 21895 checklistsOct 22-31: 0% of 28319 checklistsNov 1-7: 0% of 21698 checklistsNov 8-14: 0% of 21061 checklistsNov 15-21: 0.1% of 19855 checklistsNov 22-30: 0% of 25798 checklistsDec 1-7: 0% of 18626 checklistsDec 8-14: 0% of 19004 checklistsDec 15-21: 0% of 23103 checklistsDec 22-31: 0.1% of 30802 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 Colorado 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.

Embed this map on your site

Where in Colorado

Best counties

Share of checklists at the peak
  1. Montrose CountyBest the second week of June · 445 checklists that week, 16,168 in all21%
  2. Ouray CountyBest early July · 274 checklists that week, 10,572 in all18%
  3. Montezuma CountyBest late June · 439 checklists that week, 15,992 in all14%
  4. Mesa CountyBest the second week of June · 927 checklists that week, 45,553 in all13%
  5. Mineral CountyBest the second week of July · 136 checklists that week, 1,750 in all10%
  6. El Paso CountyBest late June · 2494 checklists that week, 104,376 in all9.2%

Best spots

Share of checklists at the peak
  1. Valley Reservoir Number OneEl Paso County, best mid June · 105 checklists that week, 3,638 in all86%
  2. Deer Creek ParkJefferson County, best late June · 20 checklists that week, 759 in all85%
  3. Matthews/Winters ParkJefferson County, best early May · 32 checklists that week, 502 in all77%
  4. Meadow ParkBoulder County, best late June · 21 checklists that week, 160 in all74%
  5. Red Rocks ParkJefferson County, best the second week of June · 45 checklists that week, 1,764 in all68%
  6. Watson LakeLarimer County, best mid April · 56 checklists that week, 2,081 in all68%

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

Best time of day

In Colorado, the White-throated Swift is most often listed on checklists started between 5 and 7 pm (1.6% of those checklists).

0%0.5%1%1.5%2%12 am: too few checklists (512) to judge1 am: too few checklists (468) to judge2 am: too few checklists (513) to judge3 am: too few checklists (656) to judge4 am: too few checklists (1918) to judge5 am: too few checklists (16045) to judge6 am: 1.5% of 71991 checklists7 am: 1.4% of 159189 checklists8 am: 1.5% of 177206 checklists9 am: 1.5% of 165269 checklists10 am: 1.5% of 141029 checklists11 am: 1.3% of 115283 checklists12 pm: 1.2% of 96068 checklists1 pm: 1.2% of 89512 checklists2 pm: 1.1% of 86319 checklists3 pm: 1.1% of 82496 checklists4 pm: 1.2% of 71648 checklists5 pm: 1.5% of 52445 checklists6 pm: 1.7% of 40199 checklists7 pm: too few checklists (24246) to judge8 pm: too few checklists (7986) to judge9 pm: too few checklists (2004) to judge10 pm: too few checklists (888) to judge11 pm: too few checklists (450) 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%0.1%0.1%
February0%0%0%0%
March0.1%0.1%0.2%0.6%
April1.1%2.0%2.1%2.2%
May2.0%2.6%2.9%3.1%
June3.7%3.9%3.8%3.6%
July3.4%2.9%2.4%2.2%
August1.8%1.7%1.3%1.1%
September1.0%1.1%1.3%1.0%
October0.8%0.2%0.1%0%
November0%0%0.1%0%
December0%0%0%0.1%

Neighboring states

  • Wyoming: arrives late April, 3 weeks later than Colorado
  • New Mexico: arrives early March, 4 weeks earlier than Colorado
  • Utah: arrives late March, 1 week earlier than Colorado
  • South Dakota: arrives early May, 4 weeks later than Colorado

Common questions

When do White-throated Swifts arrive in Colorado?
White-throated Swifts arrive in Colorado in early April, peak in the second week of June (3.8% of checklists), and most are gone by mid September.
When do White-throated Swifts leave Colorado?
Most White-throated Swifts have left Colorado by mid September, when reports fall below half their usual rate. Stragglers are still reported until late September.
When is the best time to see a White-throated Swift in Colorado?
The White-throated Swift is reported most often in the second week of June, on about 3.8% of Colorado checklists.
Where in Colorado are White-throated Swifts seen most often?
By county, Montrose County, Ouray County, and Montezuma County have the highest peak reporting rates for the White-throated Swift (counties with at least 200 checklists).