Tussey Migration Data

Overview

Fall raptor flights have been known to occur on Tussey Mountain for many years, with the former fire tower near  Pennsylvania Furnace Rd (5 miles southwest of the spring site) being a  popular watch site (see Merrill Wood's classic Birds of Pennsylvania),  as well as the Colerain Road near Spruce Creek. Part-time spring counts  were begun by David Brandes in March 1995 and continued through 2000  with the help of Dan Ombalski, Nick Bolgiano, Chuck Widmann and other  local die-hards. Full-time counts have been conducted from late Feb  through April since 2001. Although conventional wisdom maintained that  raptors do not follow ridges in the spring, we learned quickly that this did not apply to early season golden eagles.


Summary data can be found at HawkCount   

Flight Description

  •  The first three weeks of March is the peak time for  golden eagles, although the flight can be delayed by wintry weather (as in 2011 and 2017). Look in particular for warm southerly winds in early March, such as occurs ahead of approaching rain or snow
  • A large fraction of the eagles at Tussey are breeding-age,  thus the early flight as compared to other hawkwatch sites in the northeast where many of the eagles passing are non-breeding  juveniles (e.g., Braddock Bay and Derby Hill, NY). Other early raptor  species include turkey vultures, red-tails, red-shoulders and rough-legs. 
  • April is the best month for big numbers of raptors, although the flight  is highly weather-dependent. Warm days with southerly winds and clouds are usually good, particularly  after extended damp weather when the flights can be spectacular (e.g.  2001). Sunny days are usually not productive in April because thermal  lift is so strong that even eagles are moving at high altitudes and are  thus are very difficult to spot. 
  • Common raptor species include turkey vultures, red-tails,  broad-wings, sharp-shins, Coopers, ospreys, and kestrels. We usually see  all 16 regularly-occurring species of eastern diurnal raptors each spring. Swainson's hawk has also been seen on 3 separate occasions.

Seasonal Records

  • Osprey = 272 in 2001
  • Bald Eagle = 51 in 2008
  • Northen Harrier = 125 in 2001
  • Sharp-shinned = 628 in 2001
  • Cooper's = 172 in 2001
  • N Goshawk = 6 in 2005
  • Red-shouldered = 82 in 2005
  • Broad-winged = 3599 in 2001
  • Swainson's = 1 (multiple years)
  • Red-tailed = 963 in 2001
  • Rough-legged = 18 in 2005
  • Golden Eagle = 239 in 2015
  • Am Kestrel = 167 in 2001
  • Merlin = 16 in 2001
  • Peregrine = 5 in 2001

Daily Records

  • Osprey = 83 on 4/27/17
  • Bald Eagle = 14 on 3/03/08
  • Northen Harrier = 46 on 4/08/01
  • Sharp-shinned = 161 on 4/08/01
  • Cooper's = 32 on 4/12/01
  • N Goshawk = 2 on 3/12/05
  • Red-shouldered = 24 on 3/14/14
  • Broad-winged = 2173 on 4/12/01
  • Swainson's = 1 (3 records)
  • Red-tailed = 227 on 4/08/01
  • Rough-legged = 4 (various dates)
  • Golden Eagle =62 on 3/03/08
  • Am Kestrel = 42 on 4/08/01
  • Merlin = 3 on 4/23/01 and 3/30/05
  • Peregrine = 1 (various dates)

This plot shows the cumulative distribution of GOEAs counted by date


Same data as above, plotted as daily counts