Annual counts | Distribution (time of day, week) | Changes (last 8 yrs) | Links | Articles | Sources
The Chimney Rock Hawk Watch accessible via a paved trail from the parking lot at the end of Miller Ln. off of Vosseller Ave. just north of Rt. 22 in Martinsville was started in 1990 by Christopher Aquila. Chris coordinates a group of birders which staff the site from September 1 to November 15. You can learn a lot by just standing around and listening to them call out sightings.
You will usually get 2-5 days between September 12th and 25th, where Large kettles of broad winged hawks form over Chimney Rock, occasionally with 1,000 or more birds and more than 7,000 in a day.
There are local groups of turkey vultures which just circle around the area; Novices frequently mistake them for hawks. The vultures are just hanging around, while the hawks and eagles are moving NE to SW.
Cumulative Total Sightings ||
2012 appears to be another banner year. Comparisons after the large broad wing flights toward the end of Sept.
§ Count stoped on Nov. 15 in recent years
Most of the variability comes from Sept 15-25 which usually accounts for 40-70% of the total; The number of sightings from Sept 25 to Nov 15 on the lowest year, 2003, was 1,800 and on the highest year, 1996, was 24,500.
Sitings on any given day will vary considerably (from only a few to 7,000 or more) depending on wind direction. See wind below.
Median hawks per day (1997-2001)
Distribution by time of day
5 Year average sightings per day (1997-2001)
weather. see table to right.
Counts by Wind Direction (Birds/Hr.)
* Total includes vultures starting in 2005.
Counts by Species: (thru 2005) (see changes below)
One day count distribuition for|
Sep. 15-30 (Av. 1997-2001)
- Species Records thru 2005 by John Kee
- A Five Year Analysis of Autumn Hawk Migration at Chimney Rock, Martinsville, N.J. (1990-1994) , by Christopher D. Aquila & Steven B. Byland
- Species Records Page and Flight Distribution
Pictures in Bird Watching.
Sources: chimneyrock.s5.com by John Kee
Hawk Migration Assiciation of North America's (HMANA) hawkcount.org
There are a variety of factors which more experienced birders have proposed to account for the decline. I couldn't find any definitive studies.
"Using Autumn Hawk Watch to Track Raptor Migration and to Monitor Populations of North American Birds of Prey" - Article on Sharp Shinned migration decline - USDA Forest Service Gen. Tech. Rep. PSW-GTR-191. 2005
Demography and Populations -- Sharp-shinned Hawk -- Birds of North America Online at Cornell says:. (Requires subscription: $5/mo, $42/yr)
Conservation Status Report - Sharp-shinned Hawk, 2007 at HawkMountain.org states:
Fall Raptor Migration over Lake Erie Metro Park (increasing)
Saving Migratory Birds for Future Generations: The Success of the Neotropical Migratory Bird Conservation Act, Compiled by American Bird Conservancy, May 2009
A Feb. 2009 Audubon Society study found that more than half of 305 birds species in North America, a hodgepodge that includes robins, gulls, chickadees and owls, are spending the winter about 35 miles farther north than they did 40 years ago.
Potential Impacts of Global Climate Change on Bird Communities of the Southwest by Charles van Riper III, Mark K. Sogge, and David W. Willey Biological Resources Division U.S. Geological Survey
Species mix Chimney Rock vs Cape May:
Other Hawk Watch Sites:
* Racoon Ridge only counted for 9 days in Sept. 2002
* Sunrise Mountain only had counts for 13 days in Sept. 2002
Some sites keep Spring totals also (Feb-May) which are about 1/3 of Fall totals.
Other New Jersey sites at: New Jersey Sites, Hawk Migration Assiciation of North America (HMANA)
and the JerseyBirds mail list.
Scherman-Hoffman Wildlife Sanctuary (New Jersey Audubon Society)
Typical Broad winged hawks migration:
Sept. 10 - Lake Ontario
Sept. 15 - Mass.
Sept. 17 - NJ and PA
Oct. -1 - Texas
They may not fly on some days because of weather or the need to refuel so the average from above is 65-90 miles per day.
Red-Tails and others tend to be later.
Hawks will fly around 10 hours per day and travel from 100 to 250 miles.
Ducks and geese might travel as much as 400 to 500 miles per day.
Raptors fly from 29-40 MPH at an elevation of 700 - 4,000 ft.
Migration may have as much to do with availability of food as weather.
Flyways And Byways at 10000birds.com
New Jersey Osprey Project
Tails of Birding: Where Do the Hawks Go?
Random House Atlas of Bird Migration: Tracing the Journey's of the World's Birds, 1995
Bird Watching Here
Return to: Martinsville Information