Chestnut Ridge Hawk Watch - 2001
Species Accounts
Click for
Seasonal Summary
In each of the species accounts that follow, comparisons of
this year’s total with average totals from past seasons are included by using
a birds per 400 observation hours figure. This helps factor out variable amounts
of coverage from season to season, and we feel is more easily grasped than a
birds per hour figure.
Black Vulture (Coragyps atratus)
A total of 6 Black Vultures was recorded in the 2001
season, compared to last year’s 18. The high for a daily total was 2 on Sept.
30. No real conclusions can be drawn from such a small sample size beyond a
clear long-term increase in the Westchester area (as well as in much of the
Northeast U.S.).
2001: 6.3/400 hrs.
Last 18 years: 1.5
1st 9: 0.0
Last 9: 3.3
Turkey Vulture (Cathartes aura)
A total of 759 Turkey Vultures was recorded in
2001, with a daily high of 94 on Oct. 29. This was down from 2,028 in 2000,
which was the highest single season total in Chestnut Ridge’s history.
The decrease from last year is probably weather-related, as
2000 saw unusually strong and consistent northwest winds for several weeks in
November (Johansson, 2000), ideal conditions for Turkey Vulture migration. This
year’s more typical weather patterns during vulture migration, and lack of a
hawk watch intern are probably responsible for this year’s decline in vulture
totals.
2001: 796.9/400 hrs.
Last 18 years: 557.1
1st 9: 421.3
Last 9: 715.1
Osprey (Pandion haliaetus)
Only 241 Ospreys were counted, down from last year’s
327, with a high of 21 on Sept. 19. The 253.0/400 hrs. compares to 284.5 for the
hawk watch’s total history, and to 301.1 for its 1st 9 years, and 265.1 for
its last 9.
The decline from last year in Osprey totals may be just due to
less favorable weather conditions and lack of an intern. Chestnut Ridge’s
long-term data show a long-term decline, although the species has increased in
the Northeast as a breeder following 1974’s ban on DDT.
Bald Eagle (Haliaeetus leucocephalus)
27 Bald Eagles were counted, with a high of 5 on
Sept. 6. The Bald Eagle has shown a heartening continent wide increase since DDT
was banned, and Chestnut Ridge’s data bear this out. The long term data for
Bald Eagle are as follows:
2001: 28.4/400 hrs.
Last 18 years: 13.7
1st 9: 8.2
Last 9: 20.0
Northern Harrier (Circus cyaneus)
A total of 92 Northern Harriers was recorded, with
a remarkable single-day high of 19 on Oct. 17. The Northern Harrier has been
declining in the Northeast in recent decades, probably due to reforestation and
development of the meadows and wetlands it prefers for nesting. Chestnut Ridge’s
data reflect this decline.
2001: 96.6/400 hrs.
Last 18 years: 107.5
1st 9: 123.6
Last 9: 88.7
Sharp-shinned Hawk (Accipiter striatus)
A total of 1,898 Sharp-shinned Hawks was recorded, making this
species the second most abundant migrant this season at Chestnut Ridge. The
single-day high was 106, on Oct. 9. This species has shown a dramatic decline at
migration sites throughout the Northeast in the last decade or so, and Chestnut
Ridge has been no exception to this trend. One theory goes that Sharp-shins have
been wintering farther north as a result of global warming and/or increased
winter prey availability due to the proliferation of bird feeders. Other factors
may include competition from the increasing Cooper’s Hawk, which occupies a
similar ecological niche.
2001: 1992.7/400 hrs.
Last 18 years: 1,905.1
1st 9: 2,262.2
Last 9: 1,489.8
Cooper’s Hawk (Accipiter cooperii)
271 Cooper’s Hawks were counted, a decline from last year
but higher than average for the past 9 years. The single-day high was 32 on Oct.
16. This species has shown a remarkable increase in the Northeast
in recent years, probably mostly a rebound from the days of DDT.
2001: 284.5/400 hrs.
Last 18 years: 165.0
1st 9: 112.1
Last 9: 226.5
Northern Goshawk (Accipiter gentilis)
8 Northern Goshawks were recorded, with a high of 2 on Oct.
28. The numbers of this irruptive species are quite variable from year to year,
with this year’s total not far from the (last) nine-year average.
2001: 8.4/400 hrs.
Last 18 years: 10.5
1st 9: 9.2
Last 9: 12.1
Red-shouldered Hawk (Buteo lineatus)
A total of 111 Red-shouldered Hawks was recorded, with a high
of 24 on Oct. 29. This is a good season total, as the long-term data below show.
Red-shouldered numbers at Chestnut Ridge tend to vary widely from year to year.
Faherty suggests this may be due to a “type of two year boom/bust
reproductive cycle”. Yearly totals starting in 1983 go as follows: 87, 59,
188, 78, 147, 68, 147, 130, 81, 119, 51, 28, 169, 184, 148, 80, 203, 84, and 111
this year (2001). One factor affecting this may be widely fluctuating amounts of
mast from year to year in the areas to the north of us where Red-shouldereds
breed. Eastern Chipmunk and Red Squirrel numbers from year to year are strongly
affected by how many beechnuts and other seeds (“mast”) are available to
them throughout the winter, and at least chipmunks are an important food for
young Red-shouldered Hawks. There was an exceptionally large
mast crop in the fall of 2000 in New Hampshire and Vermont, and massive numbers
of chipmunks and Red Squirrels the following summer. Perhaps this accounts in
part for the higher number of Red-shouldereds this year, by helping the young
survive at a higher rate than in years with less food available. Weather may
also have had an effect, as Red-shouldereds prefer calmer days for migrating,
and last year saw prolonged, unusually strong winds in early November, near the
peak of Red-shouldered Hawk migration.
2001: 116.5/400 hrs.
Last 18 years: 82.2
1st 9: 73.5
Last 9: 92.5
Broad-winged Hawk (Buteo platyperus)
The 5,418 Broad-winged Hawks this fall was only about 49% of
last year’s 11,096, but still enough to make this species the most abundant
migrant recorded this year at Chestnut Ridge, as is usual. The largest flight
was on Sept. 15, when 2,336 were recorded. Many Broad-wings seem to have migrated
farther to the west and inland this year than last, with exceptionally high
totals recorded at many hawk watches in the inland Northeast, and especially the
Midwest.
2001: 5,688.2/400 hrs.
Last 18 years: 6,214.7
1st 9: 6,874.7
Last 9: 5,447.2
Red-tailed Hawk (Buteo jamaicensis)
303 Red-tailed hawks were counted, with a high of 124 on Oct.
28. 303 is a low season total, and may indicate that with warmer than usual
weather and lack of snow cover to our north, fewer Red-tails migrated as far
south this year than is usual. Bad weather and reduced coverage are also
probably partly responsible.
As well, Red-tails are notoriously difficult to count at
Chestnut Ridge, since there are many resident birds that are difficult to
separate from the migrants. This element of judgment required in deciding which
birds to count may make Red-tail numbers recorded tend to fluctuate from year to
year more than other species, especially when different people conduct the count
from season to season.
2001: 318.1/400 hrs.
Last 18 years: 413.7
1st 9: 351.5
Last 9: 486.0
Golden Eagle (Aquila chrysaetos)
8 Golden Eagles were seen this fall, with a high of 2 on Oct.
15. This species seems to have increased as a migrant in the Northeast recently,
as Chestnut Ridge’s long-term data support.
2001: 8.4/400 hrs.
Last 18 years: 4.4
1st 9: 3.1
Last 9: 5.9
American Kestrel (Falco sparverius)
370 American Kestrels were recorded, with highs of 37 on Sept.
12 and 26. This is the lowest season total since 1992’s 367. This species,
like the Northern Harrier, has been declining in the Northeast, probably due to
widespread reforestation and development of open fields in the area, which this
small raptor uses during the breeding season.
2001: 388.5/400 hrs.
Last 18 years: 473.9
1st 9: 498.7
Last 9: 445.1
Merlin (Falco columbarius)
46 Merlins were totaled, with a high of 6 on Oct. 24. The
Merlin has shown an increase as both a migrant and breeder in the Northeast
in the last few years, with many new breeding locations having been discovered
recently in the Adirondacks and Northern New England. Chestnut Ridge’s
long-term numbers reflect this increase.
2001: 48.3/400 hrs.
Last 18 years: 29.6
1st 9: 25.0
Last 9: 35.0
Peregrine Falcon (Falco peregrinus)
Only 6 Peregrine Falcons were seen, with a high of 3 on Oct.
13. Although Chestnut Ridge’s data show only a slight increase over the years,
this species has made a spectacular recovery in North America since the banning
of DDT and reintroduction programs in the East. Chestnut Ridge’s Peregrine
numbers are always fairly low, since this is a primarily coastal migrant.
2001: 6.3/400 hrs.
Last 18 years: 10.8
1st 9: 9.8
Last 9: 12.0
Unidentified Birds
Accipiter 123
Buteo 34
Falcon 17
Raptor/Vulture 51
Click for
Seasonal Summary
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