WhenToBird

Calidris bairdii · Scolopacidae

When Do Baird's Sandpipers Arrive in Colorado?

Adult Baird's Sandpiper
Photo: Dan Vickers, CC BY 4.0 via iNaturalist

Baird's Sandpipers mostly pass through Colorado: the first show up in mid July, they are common by late July, peak in early September (5.5% of checklists), and most are gone by late September.

When to look

First arrivalsJul 15-21mid July
Common byJul 22-31late July
PeakSep 1-7early September
Most gone bySep 22-30late September

Best: early September. First arrivals mid July; most are gone by late September. Peak: on about 5.5% of Colorado checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Marrare
  4. Apruncommon
  5. Mayuncommon
  6. Junnot usually seen
  7. Juluncommon
  8. Augpeak season
  9. Seppeak season
  10. Octuncommon
  11. Novnot usually seen
  12. Decnot usually seen

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

0%2%4%6%Jan 1-7: 0% of 32254 checklistsJan 8-14: 0% of 23278 checklistsJan 15-21: 0% of 22933 checklistsJan 22-31: 0% 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: 0.1% of 24797 checklistsMar 22-31: 0.3% of 38439 checklistsApr 1-7: 0.5% of 31676 checklistsApr 8-14: 1.0% of 35092 checklistsApr 15-21: 1.5% of 36778 checklistsApr 22-30: 1.2% of 50885 checklistsMay 1-7: 1.2% of 44186 checklistsMay 8-14: 0.6% of 49011 checklistsMay 15-21: 0.3% of 40784 checklistsMay 22-31: 0.2% of 53073 checklistsJun 1-7: 0.1% of 32432 checklistsJun 8-14: 0.1% of 29978 checklistsJun 15-21: 0.1% of 29457 checklistsJun 22-30: 0.1% of 36072 checklistsJul 1-7: 0.1% of 28857 checklistsJul 8-14: 0.4% of 27224 checklistsJul 15-21: 0.9% of 27629 checklistsJul 22-31: 2.1% of 37318 checklistsAug 1-7: 2.3% of 25893 checklistsAug 8-14: 3.7% of 24870 checklistsAug 15-21: 4.5% of 24035 checklistsAug 22-31: 5.8% of 35691 checklistsSep 1-7: 5.7% of 27068 checklistsSep 8-14: 4.9% of 26709 checklistsSep 15-21: 3.1% of 26098 checklistsSep 22-30: 2.1% of 31550 checklistsOct 1-7: 1.3% of 24110 checklistsOct 8-14: 1.0% of 23352 checklistsOct 15-21: 0.6% of 21895 checklistsOct 22-31: 0.3% of 28319 checklistsNov 1-7: 0.2% of 21698 checklistsNov 8-14: 0.1% of 21061 checklistsNov 15-21: 0.1% of 19855 checklistsNov 22-30: 0.1% of 25798 checklistsDec 1-7: 0.1% of 18626 checklistsDec 8-14: 0.1% of 19004 checklistsDec 15-21: 0% of 23103 checklistsDec 22-31: 0% 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.

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Where in Colorado

Best counties

Share of checklists at the peak
  1. Washington CountyBest the second week of August · 37 checklists that week, 2,511 in all63%
  2. Sedgwick CountyBest mid September · 38 checklists that week, 1,168 in all45%
  3. Morgan CountyBest early September · 153 checklists that week, 5,181 in all35%
  4. Crowley CountyBest mid August · 100 checklists that week, 1,883 in all33%
  5. Kiowa CountyBest mid July · 42 checklists that week, 3,854 in all33%
  6. Costilla CountyBest early September · 24 checklists that week, 1,323 in all28%

Best spots

Share of checklists at the peak
  1. Prewitt Reservoir State Wildlife AreaWashington County, best early August · 30 checklists that week, 957 in all88%
  2. Gaynor LakeBoulder County, best late August · 68 checklists that week, 676 in all82%
  3. Jackson Lake State Wildlife AreaMorgan County, best early September · 22 checklists that week, 276 in all80%
  4. Timnath ReservoirLarimer County, best early August · 50 checklists that week, 1,723 in all77%

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

Best time of day

In Colorado, the Baird's Sandpiper is most often listed on checklists started between 5 and 7 pm (1.2% of those checklists).

0%0.5%1%1.5%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: 1.3% of 71991 checklists7 am: 1.0% of 159189 checklists8 am: 0.9% of 177206 checklists9 am: 1.0% of 165269 checklists10 am: 0.9% of 141029 checklists11 am: 0.9% of 115283 checklists12 pm: 1.0% of 96068 checklists1 pm: 0.9% of 89512 checklists2 pm: 1.0% of 86319 checklists3 pm: 1.0% of 82496 checklists4 pm: 1.0% of 71648 checklists5 pm: 1.2% of 52445 checklists6 pm: 1.3% 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%0%0%0%
February0%0%0%0%
March0.1%0.1%0.1%0.3%
April0.5%1.0%1.5%1.2%
May1.2%0.6%0.3%0.2%
June0.1%0.1%0.1%0.1%
July0.1%0.4%0.9%2.1%
August2.3%3.7%4.5%5.8%
September5.7%4.9%3.1%2.1%
October1.3%1.0%0.6%0.3%
November0.2%0.1%0.1%0.1%
December0.1%0.1%0%0%

Neighboring states

  • Wyoming: arrives mid July, in the same week than Colorado
  • New Mexico: arrives late July, 1 week later than Colorado
  • Utah: arrives early August, 2 weeks later than Colorado
  • Nebraska: arrives late March, 15 weeks earlier than Colorado

Common questions

When do Baird's Sandpipers arrive in Colorado?
Baird's Sandpipers mostly pass through Colorado: the first show up in mid July, they are common by late July, peak in early September (5.5% of checklists), and most are gone by late September.
When do Baird's Sandpipers leave Colorado?
Most Baird's Sandpipers have left Colorado by late September, when reports fall below half their usual rate. Stragglers are still reported until early October.
When is the best time to see a Baird's Sandpiper in Colorado?
The Baird's Sandpiper is reported most often in early September, on about 5.5% of Colorado checklists.
Where in Colorado are Baird's Sandpipers seen most often?
By county, Washington County, Sedgwick County, and Morgan County have the highest peak reporting rates for the Baird's Sandpiper (counties with at least 200 checklists).