WhenToBird

Birding spot · Boulder County, Colorado

Birding at Hillcrest Reservoir: What You'll See Each Week

In November, the birds most often reported at Hillcrest Reservoir are American Coot (79%), Black-billed Magpie (79%), and Common Merganser (79%). It is busiest in summer, when 57 species turn up on at least 1 in 20 checklists, and species counts peak in the second week of October (78 species). 141 species have been reported here across 1,078 complete checklists from 348 birders.

Species by week

020406080Jan 1-7: 41 species on 5%+ of 123 checklistsJan 8-14: 44 species on 5%+ of 76 checklistsJan 15-21: 36 species on 5%+ of 58 checklistsJan 22-31: 42 species on 5%+ of 34 checklistsFeb 1-7: 36 species on 5%+ of 25 checklistsFeb 8-14: low data (7 checklists)Feb 15-21: 33 species on 5%+ of 13 checklistsFeb 22-28: 41 species on 5%+ of 19 checklistsMar 1-7: 32 species on 5%+ of 22 checklistsMar 8-14: 39 species on 5%+ of 26 checklistsMar 15-21: 42 species on 5%+ of 14 checklistsMar 22-31: 43 species on 5%+ of 31 checklistsApr 1-7: 47 species on 5%+ of 15 checklistsApr 8-14: 44 species on 5%+ of 22 checklistsApr 15-21: low data (9 checklists)Apr 22-30: 55 species on 5%+ of 14 checklistsMay 1-7: 52 species on 5%+ of 14 checklistsMay 8-14: low data (6 checklists)May 15-21: low data (7 checklists)May 22-31: 63 species on 5%+ of 16 checklistsJun 1-7: 53 species on 5%+ of 20 checklistsJun 8-14: low data (7 checklists)Jun 15-21: low data (5 checklists)Jun 22-30: low data (5 checklists)Jul 1-7: low data (1 checklists)Jul 8-14: low data (5 checklists)Jul 15-21: low data (3 checklists)Jul 22-31: 42 species on 5%+ of 11 checklistsAug 1-7: low data (5 checklists)Aug 8-14: low data (5 checklists)Aug 15-21: low data (3 checklists)Aug 22-31: low data (6 checklists)Sep 1-7: 70 species on 5%+ of 19 checklistsSep 8-14: 55 species on 5%+ of 15 checklistsSep 15-21: 71 species on 5%+ of 20 checklistsSep 22-30: 56 species on 5%+ of 12 checklistsOct 1-7: 50 species on 5%+ of 12 checklistsOct 8-14: 78 species on 5%+ of 20 checklistsOct 15-21: 66 species on 5%+ of 19 checklistsOct 22-31: 48 species on 5%+ of 43 checklistsNov 1-7: 49 species on 5%+ of 25 checklistsNov 8-14: 51 species on 5%+ of 37 checklistsNov 15-21: 53 species on 5%+ of 20 checklistsNov 22-30: 47 species on 5%+ of 30 checklistsDec 1-7: 42 species on 5%+ of 33 checklistsDec 8-14: 51 species on 5%+ of 40 checklistsDec 15-21: 32 species on 5%+ of 45 checklistsDec 22-31: 43 species on 5%+ of 61 checklistsJanFebMarAprMayJunJulAugSepOctNovDec
Number of species reported on at least 5% of complete checklists, by week (4 per month). Grey bars: fewer than 10 checklists, not counted.

In November: what to expect

  1. 1American Coot79%
  2. 2Black-billed Magpie79%
  3. 3Common Merganser79%
  4. 4Ring-billed Gull79%
  5. 5Hooded Merganser69%
  6. 6Canada Goose57%
  7. 7Red-breasted Merganser52%
  8. 8Red-tailed Hawk48%
  9. 9European Starling45%
  10. 10Canvasback44%
  11. 11Common Goldeneye43%
  12. 12Pied-billed Grebe41%
  13. 13Redhead39%
  14. 14Gadwall38%
  15. 15Western Grebe38%

Share of complete checklists at this spot that reported the bird in November. The sparkline is the whole year, with this month highlighted.

Season by season

Winter 39 species

  1. Common Merganser82%
  2. Black-billed Magpie80%
  3. Ring-billed Gull74%
  4. American Coot66%
  5. Common Goldeneye58%

Spring 56 species

  1. Black-billed Magpie81%
  2. Common Merganser63%
  3. Red-breasted Merganser55%
  4. American Coot49%
  5. Red-tailed Hawk48%

Summer 57 species

  1. Canada Goose88%
  2. Black-billed Magpie82%
  3. Double-crested Cormorant74%
  4. Western Grebe74%
  5. Osprey64%

Fall 57 species

  1. American Coot88%
  2. Black-billed Magpie81%
  3. Ring-billed Gull78%
  4. Canada Goose72%
  5. Western Grebe59%

Specialties

Birds reported far more often here than across Colorado.

Nearby spots

Frequency is the share of complete checklists at this location that listed the bird, 2016–2025. Busy places report more of everything, and the weekly chart counts species on at least 5% of checklists so a few stray reports do not inflate it. How to read it.