Migration Statistics

Season Statistics

Each fall, Hawk Ridge averaged 76,000 migrating raptors from 1991-2013 and, using a different sampling procedure, averaged 39,000 raptors from 1972-1990.

In addition to the common raptors, listed below, other raptor species recorded include:

  • Black Vulture: one record (2000)
  • Mississippi Kite: 1-3 observed in eleven years (1991-2013)
  • Red-shouldered Hawk: 1-8 observed in 21 years (1990-2013), peak timing in Oct
  • Swainson’s Hawk: 2-10 birds observed most years, peak timing in Sept
  • Gyrfalcon: one bird observed in eleven years (1972-2013)
  • Prairie Falcon: three records (1979, 1991, 1993)

Statistics of Common Raptors

Image Credits: Brent Alan Kauth

Turkey Vulture
Peak Migration: mid Sep - mid Oct
Record Daily High: 799 on 29 Sep 1996
Record Seasonal High: 1776 in 2003

Osprey
Peak Migration: 1 Sep - 30 Sep
Record Daily High: 90 on 17 Sep 1997
Record Seasonal High: 534 in 1998

Bald Eagle
Peak Migration: Sept - Nov
Record Daily High: 743 on 22 Nov 1994
Record Seasonal High: 5,778 in 2011

Northern Harrier
Peak Migration: Sept – Oct
Record Daily High: 216 on 17 Sep 1994
Record Seasonal High: 1,100 in 1999

Sharp-shinned Hawk (Accipiter striatus)
Peak Migration: 1 Sep - 15 Oct
Record Daily High: 2,040 on 8 Oct 2003
Record Seasonal High: 21,352 in 1997

Cooper’s Hawk (Accipiter cooperii)
Peak Migration: early Sept – early Oct
Record Daily High: 45 on 14 Sep 2000
Record Seasonal High: 319 in 1993

Northern Goshawk (Accipiter gentilis)
Peak Migration: Oct – Nov
Record Daily High: 1,229 on 15 Oct 1982
Record Seasonal High: 5,819 in 1972

Broad-winged Hawk
Peak Migration: 10 Sep - 25 Sep
Record Daily High: 101,716 on 15 Sep 2003
Record Seasonal High: 160,776 in 2003

Red-tailed Hawk
Peak Migration: 1 Oct – 31 Oct
Record Daily High: 3,991 on Oct. 24, 1994
Record Seasonal High: 15,358 in 1994

Rough-legged Hawk
Peak Migration: mid Oct – Nov
Record Daily High: 204 on 10 Nov 1963
Record Seasonal High: 1,026 in 1994

Golden Eagle
Peak Migration: late Oct – late Nov
Record Daily High: 29 on 26 Oct 2001
Record Seasonal High: 223 in 2009

Great Horned Owl
Earliest Date: Oct 15
Latest Date: Dec 8
Peak Migration: after Nov 15

Barred Owl
Earliest Date: Sep 30
Latest Date: Dec 1
Peak Migration: 15 - 31 Oct

Long-eared Owl
Earliest Date: Sep 4
Latest Date: Nov 19
Peak Migration: 15 - 31 Oct

Short-eared Owl
Earliest Date: 29 Sept
Latest Date: 31 Oct
Peak Migration: mid-Oct

Boreal Owl
Earliest Date: Oct 11
Latest Date: Nov 19
Peak Migration: 20 Oct - 5 Nov

Northern Saw-whet Owl
Earliest Date: Aug 17
Latest Date: Nov 16
Peak Migration: 1 – 31 Oct

American Kestrel
Peak Migration: early Sept – early Oct
Record Daily High: 744 on 9 Sep 2002
Record Seasonal High: 3,637 in 2002

Merlin
Peak Migration: early Sept – mid-Oct
Record Daily High: 73 on 9 Oct 1998
Record Seasonal High: 362 in 1997

Peregrine Falcon
Peak Migration: Sept – early Oct
Record Daily High: 21 on 29 September 1997
Record Seasonal High: 154 in 2013

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