WhenToBird

Astur cooperii · Accipitridae

When Do Cooper's Hawks Arrive in Connecticut?

Adult male Cooper's Hawk
Photo: Shirley Zundell, CC BY 4.0 via iNaturalist

Cooper's Hawks are winter birds in Connecticut: the first arrive in late July, they are common by the second week of August, peak in the second week of October (12% of checklists), and most are gone by late April.

When to look

First arrivalsJul 22-31late July
Common byAug 8-14the second week of August
PeakOct 8-14the second week of October
Most gone byApr 22-30late April

Best: the second week of October. First arrivals late July; most are gone by late April. Peak: on about 12% of Connecticut checklists.

  1. Januncommon
  2. Febuncommon
  3. Maruncommon
  4. Apruncommon
  5. Mayuncommon
  6. Jununcommon
  7. Juluncommon
  8. Augcommon
  9. Seppeak season
  10. Octpeak season
  11. Novpeak season
  12. Deccommon

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

0%5%10%15%Jan 1-7: 4.3% of 18950 checklistsJan 8-14: 4.6% of 13676 checklistsJan 15-21: 4.5% of 13377 checklistsJan 22-31: 3.8% of 17004 checklistsFeb 1-7: 3.8% of 10218 checklistsFeb 8-14: 3.9% of 11568 checklistsFeb 15-21: 2.9% of 15916 checklistsFeb 22-28: 2.3% of 11413 checklistsMar 1-7: 2.3% of 10754 checklistsMar 8-14: 2.6% of 12051 checklistsMar 15-21: 2.7% of 12616 checklistsMar 22-31: 2.8% of 17801 checklistsApr 1-7: 2.9% of 13186 checklistsApr 8-14: 3.5% of 14428 checklistsApr 15-21: 3.7% of 14738 checklistsApr 22-30: 3.2% of 21753 checklistsMay 1-7: 2.7% of 22494 checklistsMay 8-14: 2.3% of 23363 checklistsMay 15-21: 1.8% of 20219 checklistsMay 22-31: 1.6% of 20778 checklistsJun 1-7: 1.6% of 12234 checklistsJun 8-14: 1.9% of 12491 checklistsJun 15-21: 2.0% of 10856 checklistsJun 22-30: 1.7% of 11964 checklistsJul 1-7: 1.7% of 9437 checklistsJul 8-14: 1.7% of 8599 checklistsJul 15-21: 1.7% of 8252 checklistsJul 22-31: 2.0% of 11329 checklistsAug 1-7: 3.0% of 8116 checklistsAug 8-14: 2.9% of 8051 checklistsAug 15-21: 4.7% of 8502 checklistsAug 22-31: 4.7% of 13673 checklistsSep 1-7: 5.7% of 9873 checklistsSep 8-14: 6.3% of 9735 checklistsSep 15-21: 10% of 10120 checklistsSep 22-30: 10% of 12543 checklistsOct 1-7: 11% of 10735 checklistsOct 8-14: 13% of 10869 checklistsOct 15-21: 12% of 10436 checklistsOct 22-31: 11% of 13808 checklistsNov 1-7: 9.0% of 10507 checklistsNov 8-14: 8.2% of 9827 checklistsNov 15-21: 7.1% of 9904 checklistsNov 22-30: 6.1% of 13396 checklistsDec 1-7: 5.7% of 8974 checklistsDec 8-14: 5.3% of 9468 checklistsDec 15-21: 6.1% of 11614 checklistsDec 22-31: 4.6% of 16616 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 Connecticut 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 Connecticut

Best counties

Share of checklists at the peak
  1. New Haven CountyBest the second week of October · 2651 checklists that week, 139,721 in all18%
  2. Fairfield CountyBest mid October · 2417 checklists that week, 139,848 in all15%
  3. New London CountyBest early October · 1011 checklists that week, 65,205 in all10%
  4. Tolland CountyBest early October · 770 checklists that week, 39,004 in all9.6%
  5. Windham CountyBest early October · 266 checklists that week, 19,034 in all8.4%
  6. Hartford CountyBest mid October · 1796 checklists that week, 105,735 in all7.9%

Best spots

Share of checklists at the peak
  1. Lighthouse PointNew Haven County, best mid October · 104 checklists that week, 2,239 in all76%
  2. Veterans ParkFairfield County, best mid November · 55 checklists that week, 589 in all59%
  3. Glastonbury MeadowsHartford County, best mid September · 32 checklists that week, 683 in all58%
  4. Trout Brook ValleyFairfield County, best the second week of October · 45 checklists that week, 1,588 in all56%
  5. Audubon Center of GreenwichFairfield County, best mid October · 73 checklists that week, 1,839 in all48%

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

Best time of day

In Connecticut, the Cooper's Hawk is most often listed on checklists started between 7 and 9 am (6.3% of those checklists).

0%2%4%6%8%12 am: too few checklists (325) to judge1 am: too few checklists (367) to judge2 am: too few checklists (488) to judge3 am: too few checklists (792) to judge4 am: too few checklists (2722) to judge5 am: too few checklists (9489) to judge6 am: 5.4% of 33657 checklists7 am: 6.7% of 62964 checklists8 am: 6.0% of 70645 checklists9 am: 4.9% of 64870 checklists10 am: 4.6% of 58827 checklists11 am: 4.0% of 51689 checklists12 pm: 3.7% of 45288 checklists1 pm: 3.6% of 44765 checklists2 pm: 3.9% of 44173 checklists3 pm: 3.6% of 41979 checklists4 pm: 3.1% of 33219 checklists5 pm: 2.8% of 24828 checklists6 pm: 2.1% of 15856 checklists7 pm: too few checklists (8126) to judge8 pm: too few checklists (1994) to judge9 pm: too few checklists (533) to judge10 pm: too few checklists (349) to judge11 pm: too few checklists (286) 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
January4.3%4.6%4.5%3.8%
February3.8%3.9%2.9%2.3%
March2.3%2.6%2.7%2.8%
April2.9%3.5%3.7%3.2%
May2.7%2.3%1.8%1.6%
June1.6%1.9%2.0%1.7%
July1.7%1.7%1.7%2.0%
August3.0%2.9%4.7%4.7%
September5.7%6.3%10%10%
October11%13%12%11%
November9.0%8.2%7.1%6.1%
December5.7%5.3%6.1%4.6%

Neighboring states

  • Rhode Island: arrives late July, in the same week than Connecticut
  • Massachusetts: arrives late August, 4 weeks later than Connecticut
  • New Jersey: arrives mid September, 7 weeks later than Connecticut
  • New York: arrives mid July, 1 week earlier than Connecticut

Common questions

When do Cooper's Hawks arrive in Connecticut?
Cooper's Hawks are winter birds in Connecticut: the first arrive in late July, they are common by the second week of August, peak in the second week of October (12% of checklists), and most are gone by late April.
When do Cooper's Hawks leave Connecticut?
Most Cooper's Hawks have left Connecticut by late April, when reports fall below half their usual rate. Stragglers are still reported until the second week of May.
When is the best time to see a Cooper's Hawk in Connecticut?
The Cooper's Hawk is reported most often in the second week of October, on about 12% of Connecticut checklists.
Where in Connecticut are Cooper's Hawks seen most often?
By county, New Haven County, Fairfield County, and New London County have the highest peak reporting rates for the Cooper's Hawk (counties with at least 200 checklists).