Monitoring of Wintering Bald Eagles In Westchester and Rockland

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					       Monitoring of Wintering Bald Eagles
    In Westchester and Rockland Counties 2008
 
 
     A Project of the Bedford Audubon Society
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
               Prepared by Tait Johansson
                Bedford Audubon Society
                      July 25, 2008
Introduction
 

    The Bedford Audubon Society conducted its second Winter Eagle Monitoring Project from
December 29, 2007, to March 29, 2008. This year, the project surveyed roosting Bald Eagles (Halieetus
leucocephalus) at three sites, two in northwestern Westchester County, New York, and one just across
the Hudson River in Rockland County, New York. The purpose of this ongoing project is to help
monitor the significant concentration of wintering Bald Eagles in the Lower Hudson River Important
Bird Area. As part of this project, two Bald Eagle nests located at two of the roost sites were also
monitored.

     The Bald Eagle, our national symbol, was victim of a serious decline in numbers in the middle
part of the last century, primarily due to the widespread use of chlorinated hydrocarbons such as DDT
(Dichloro-diphenyl-trichloroethane) as pesticides. These chemicals were taken up into the eagles’
bodies through the prey they ate and interfered with their breeding physiology, resulting in eggs laid
with too-thin shells (or sometimes no shells) that broke during incubation. Since the ban on DDT for
most uses took effect in 1972, this eagle’s population has slowly but steadily climbed. In New York
State, the number of breeding pairs had increased from one in 1965 to 124 in 2007 (Nye 2007).
Although recently taken off the Endangered Species List, the Bald Eagle is still a species of
conservation concern that warrants careful monitoring of its population.

    The lower Hudson Valley is one of the most significant Bald Eagle wintering areas in the state
(Burger and Liner, 2005). Although roosts in the area are surveyed twice per winter by the New York
Department of Environmental Conservation, Bedford Audubon’s more frequent monitoring last year
(2007) revealed large, sudden, frequent fluctuations in numbers at these sites (Bielfelt 2007),
underlining the importance of more regular monitoring to truly reveal the extent of eagle usage of
these sites.

    Compared to 2007‘s project, more sites were surveyed more often and over a much longer period.
Last winter, regular monitoring was performed twice a week and started in late February 2007 and
extended till late March 2007. This season, regular monitoring was performed three times a week and
started in late December 2007 and continued until late March 2008.
 
 
 
Methods
    Observations were taken on a standardized data sheet at all three main sites, weather permitting,
(Verplanck, George’s Island, and New Croton Reservoir) every Tuesday, Thursday and Saturday
during the monitoring period (Dec. 29- March 29), with few exceptions (bad visibility sometimes made
viewing impossible at certain sites).
   Monitoring, conducted by volunteers, occurred from about 1.5 hours before sunset to dusk.
Observers recorded the date, time spent monitoring, percentage of cloud cover, percentage of visible
water covered by ice, temperature, total numbers of adult eagles roosting onsite, total number of
immature eagles roosting onsite, and general observations on the birds’ movements. Efforts were also
made to age the eagles to year if possible, and to record any other noteworthy birds or observations
occurring during the monitoring period. The data sheet is reproduced below.




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Eagle Project                                                   Observer______________________
Date:___/___/2008                                               Location: Cr.Pt / Cr. Dam/ Gr.Is/ Iona Is.

Start Time__________________                                    End Time_______________

% Cloud Cover_________                                          Temperature_____________

% Ice Cover on the Water (that you can see)_____________________

Adult Eagles:______                                             Immature Eagles:________

How many were in the trees upon arrival?________________

Approximately how many flew in from the following directions?

East____             North____            West____              South____     _____ ______
                                                                              (other)
Could you clearly see all the eagles? Y/ N
If not, what obstructed your view?______________________________

Other interesting birds or observations:




Eagle Project                                                   Observer___________________
Date:___/___/2008                                               Location: Cr.Pt / Cr. Dam/ Gr.Is? Iona Is.

Start Time__________________                                    End Time_______________

% Cloud Cover_________                                          Temperature_____________

% Ice Cover on the Water (that you can see)_____________________

Adult Eagles:______                                             Immature Eagles:________

How many were in the trees upon arrival?

Approximately how many flew in from the following directions?

East____             North____            West____              South____     _____ ______
                                                                              (other)
Could you clearly see all the eagles? Y/ N
If not, what obstructed your view?______________________________

Other interesting birds or observations:




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Results

Sites Surveyed: Descriptions

   Observations were collected at three main locations: George’s Island Park, New Croton Reservoir,
and Verplanck. The Verplanck observation site afforded views of two roost sites, which were
monitored simultaneously. Several other locations were checked during the monitoring season for
possible usage by roosting eagles, with no success: Iona Island, Croton Point Park in Cortlandt, Titicus
Reservoir in North Salem, and Cross River Reservoir in Bedford and Lewisboro.



New Croton Reservoir

    One large eagle roost was monitored at New Croton Reservoir in the towns of Yorktown and
Cortlandt, Westchester County. The monitoring was conducted from two separate locations- one on
the dam itself, and one about a mile east of the dam, just off of Croton Dam Rd. on the southern shore
of the reservoir. These two sites afforded different views of the same large eagle roost in tall, mostly
deciduous trees in and around a small cove on the north shore of the reservoir. There was also an
active Bald Eagle nest visible from the dam (see Eagle Nests section of report below).
    This was usually the largest roost surveyed, and had the consistently highest numbers.

   This roost averaged 15.68 eagles (7.21 immatures, 8.45 adults) in 38 monitoring visits from 12/29/08
to 3/29/08, with a high of 47 on 2/14/08.
 
Average numbers by month:
January average: 15.00 roosting eagles (7.14 immatures, 7.64 adults) in 14 monitoring visits February
average: 25.7 eagles (11.20 imms., 14.50 ads.) in 10 visits
March average: 9.92 eagles (4.77 imms., 5.08 ads.) in 13 visits
 
 
Date       Location   Observer(s) Total imms. Total ads. Total eagles
12/29/07   CD         Margaret Freifeld 0 0 0
12/29/07   CD         Helle Raheem, Omar Raheem 0 3 3
01/01/08   CD         Margaret Freifeld 4 2 6
01/03/08   CD         Margaret Freifeld 7 7 14
01/05/08   CD         Tait Johansson 7 5 12
01/08/08   CD         Laura Jaffee, Tait Johansson, Nannette Orr 8 6 14
01/10/08   CD         Peter Becker, Margaret Freifeld 6 0 6
01/13/08   CD         Tony Ianniello 0 1 1
01/15/08   CD         Margaret Freifeld, Nannette Orr 11 11 22
01/17/08   CD         Peter Becker, Margaret Freifeld 6 9 15
01/19/08   CD         Tait Johansson 3 5 8
01/22/08   CD         Margaret Freifeld, Allen Kurtz 4 13 17
01/24/08   CD         Margaret Freifeld, Nannette Orr 10 5 15
01/26/08   CD         Nannette Orr, Ted Raymond, Michelle Walter 6 14 20
01/29/08   CD         Margaret Freifeld, Ted Raymond 12 8 20
01/31/08   CD         Margaret Freifeld, Tait Johansson 16 21 37
02/02/08   CD         Allen Kurtz 15 21 36
02/05/08   CD         Margaret Freifeld, Tait Johansson 5 10 15
02/07/08   CD         Margaret Freifeld, Tait Johansson 17 11 28
02/09/08   CD         Tait Johansson 9 13 22
02/14/08   CD         Helle Raheem, ER 20 27 47
02/16/08   CD         Tait Johansson 8 12 20
02/19/08   CD         Margaret Freifeld, Nannette Orr 10 21 31
02/21/08   CD         Margaret Freifeld, Tait Johansson 12 18 30
02/23/08   CD         Tait Johansson 5 4 9
02/26/08   CD         Monitoring cancelled due to bad weather
02/28/08   CD          Ken Mirman 11 8 19
03/01/08   CD          Nannette Orr, Michelle Walter 16 23 39
03/04/08   CD         Margaret Freifeld, Ken Mirman 11 14 26
03/06/08   CD         Margaret Freifeld, Ken Mirman 7 3 10
03/09/08   CD          Tait Johansson, Nannette Orr, Michelle Walter 5 7 12
03/11/08   CD          Ken Mirman 1 2 3
03/13/08   CD         Margaret Freifeld, Tait Johansson 7 5 12

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03/15/08   CD       Ken Mirman 7 4 11
03/18/08   CD       Margaret Freifeld, TH 5 2 7
03/20/08   CD       Margaret Freifeld 0 2 2
03/22/08   CD       Ken Mirman 3 1 4
03/25/08   CD       Margaret Freifeld 0 1 1
03/27/08   CD       Margaret Freifeld 0 1 1
03/29/08   CD       Nannette Orr, Michelle Walter, JW 0 1 1
 


George’s Island Park
 
    George’s Island Park is a small county-managed park on the Hudson River in the Village of
Montrose, town of Cortlandt, Westchester County, New York. Observations were made of an eagle
roost on the forested southern shore of Montrose Point looking north from the area around the
northwest corner of the parking lot. The birds here mostly roosted in tall deciduous trees, many of
them Tuliptrees (Liriodendron tulipferum). Only a small part of Montrose Point was visible from the
vantage point, and it was clear that some eagles were roosting out of view just to the north on parts of
the point that were out of view (see separate description of George’s Island- North below).

    This roost averaged 7.00 roosting eagles (4.69 immatures, 2.31 adults) in 36 monitoring visits from
1/1/08 to 3/29/08, with a high of 21 on 1/5/08.
 
Average numbers by month:
January average: 9.00 roosting eagles (5.79 immatures, 3.21 adults) in 14 monitoring visits
February average: 9.70 roosting eagles (6.60 imms., 3.10 ads.) in 10 visits
March average: 2.42 roosting eagles (1.83 imms., 0.58 ads.) in 12 visits
 
 
Date Location Observer(s) Total imms. Total ads. Total eagles
01/01/08 GI Ted Raymond 1 0 1
01/03/08 GI Tony Ianniello 4 0 4
01/05/08 GI Nannette Orr, Michelle Walter 13 8 21
01/08/08 GI Tony Ianniello 0 0 0
01/10/08 GI Tony Ianniello 6 0 6
01/13/08 GI Tait Johansson, Nannette Orr 3 4 7
01/15/08 GI Tait Johansson 11 4 15
01/17/08 GI Michelle Walter 4 4 8
01/19/08 GI Michelle Walter 10 6 16
01/22/08 GI Ken Mirman 0 0 0
01/24/08 GI Ken Mirman 7 3 10
01/26/08 GI Ken Mirman 9 1 10
01/29/08 GI Allen Kurtz 9 13 22
01/31/08 GI Ken Mirman 4 2 6
02/02/08 GI Ken Mirman 8 4 12
02/05/08 GI Tony Ianniello 12 1 13
02/07/08 GI Allen Kurtz 13 4 7
02/09/08 GI Peter Becker 5 3 8
02/14/08 GI Peter Becker 1 1 2
02/16/08 GI Walter Fowler 3 5 8
02/19/08 GI Peter Becker 1 1 2
02/21/08 GI Ken Mirman 11 3 14
02/23/08 GI Ken Mirman 7 4 11
02/26/08 GI Monitoring cancelled due to bad weather
02/28/08 GI Margaret Freifeld, Nannette Orr 5 5 10
03/01/08 GI Ken Mirman 8 1 9
03/04/08 GI Tait Johansson, Nannette Orr 0 0 0
03/06/08 GI Laura Jaffee, Nannette Orr 0 1 1
03/09/08 GI Ken Mirman 12 3 15
03/11/08 GI Tait Johansson 2 2 4
03/13/08 GI Ken Mirman 0 0 0
03/18/08 GI Ken Mirman 0 0 0
03/20/08 GI Ken Mirman 0 0 0
03/22/08 GI Tait Johansson 0 0 0
03/25/08 GI Tait Johansson 0 0 0
03/27/08 GI Tait Johansson 0 0 0
03/29/08 GI Tait Johansson 0 0 0




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George’s Island-North (North side of Montrose Point)

     Monitored from a small park by the Hudson River in the village of Verplanck, town of Cortlandt,
this roost was on the forested north side of Montrose Point, the other side of the peninsula that also
holds the eagle roost monitored from George’s Island Park. Most birds here roosted in several large,
tall Tuliptrees (Liriodendron tulipferum). Frustratingly, there was a large area in the middle of
Montrose Point that was not visible from either of these two monitoring locations. This area almost
certainly held more roosting eagles. Some eagles that appeared to be flying in to roost in this non-
visible part of the point were observed at both George’s Island-North and at George’s Island Park.
These two roosts may only be the two visible parts of one larger roost on Montrose Point, but
logistically feasible visual access to the middle appears to be impossible.

   This roost averaged 5.00 roosting eagles in 23 monitoring visits., with a high of 51 on 1/26/08.
 
Average numbers by month:
January average: 30.5 roosting eagles (15.50 immatures, 5.50 adults) in 2 monitoring visits
February average: 4.67 roosting eagles in 9 visits
March average: 1.09 roosting eagles in 11 visits
 
Date Location Observer(s) Total imms. Total ads. Total eagles
01/26/08 GI-N Tait Johansson 23 9 51
01/31/08 GI-N Nannette Orr, Michelle Walter 8 2 10
02/02/08 GI-N Laura Jaffee, Nannette Orr THICK FOG 0 0 0
02/05/08 GI-N Nannette Orr, Michelle Walter 8 0 8
02/07/08 GI-N Denise Lee, E. Kellogg, Michelle Walter 0 2 2
02/09/08 GI-N Nannette Orr, Michelle Walter 14 5 19
02/14/08 GI-N Laura Jaffee, Nannette Orr 0 1 1
02/16/08 GI-N Jim Jaffee, Laura Jaffee, Nannette Orr 0 0 0
02/19/08 GI-N Tait Johansson 0 0 0
02/21/08 GI-N Michelle Walter 4 4 8
02/23/08 GI-N Michelle Walter 2 2 4
02/26/08 GI-N Monitoring cancelled due to bad weather
02/28/08 GI-N Tait Johansson 0 0 0
03/01/08 GI-N Tait Johansson 0 0 0
03/06/08 GI-N Tait Johansson 7 1 8
03/09/08 GI-N Jim Jaffee, Laura Jaffee 0 0 0
03/11/08 GI-N Allen Kurtz, Nannette Orr 0 0 0
03/15/08 GI-N Tait Johansson 2 1 4
03/18/08 GI-N Nannette Orr, Ted Raymond, JL 0 0 0
03/20/08 GI-N Tait Johansson 0 0 0
03/22/08 GI-N Tait Johansson 0 0 0
03/25/08 GI-N Tait Johansson 0 0 0
03/27/08 GI-N Nannette Orr, Michelle Walter, Jeanne Waful 0 0 0
03/29/08 GI-N Tait Johansson 0 0 0




Verplanck (Stony Point)

    This roost, monitored from the same small riverside park in Verplanck that George’s Island- North
was, was a small, intermittently used roost mostly in a group of dead Eastern Hemlocks (Tsuga
canadensis) situated on mostly forested Stony Point in Stony Point State Park, in the town of Stony
Point, Rockland County. There was also an easily seen, active eagle nest located on this peninsula next
to the roosting area (see Eagle Nests section of report below).

   This location averaged 2.25 roosting eagles in 24 monitoring visits.
 
Average numbers by month:
January average: 5.5 roosting eagles in 4 monitoring visits
February average: 1.8 roosting eagles in 10 visits
March average: 1.27 roosting eagles in 11 visits
 
Date Location Observer(s) Total imms. Total ads. Total eagles
01/22/08 VERPL Tait Johansson 9 1 10


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01/24/08 VERPL Tait Johansson 0 1 1
01/26/08 VERPL Tait Johansson 3 0 3
01/31/08 VERPL Nannette Orr, Michelle Walter 4 4 8
02/02/08 VERPL Laura Jaffee, Nannette Orr THICK FOG - totals not counted
02/05/08 VERPL Nannette Orr, Michelle Walter 0 0 0
02/07/08 VERPL Denise Lee, E. Kellogg, Michelle Walter 0 3 3
02/09/08 VERPL Nannette Orr, Michelle Walter 0 2 2
02/14/08 VERPL Laura Jaffee, Nannette Orr 3 0 3
02/16/08 VERPL Jim Jaffee, Laura Jaffee, Nannette Orr 0 2 2
02/19/08 VERPL Tait Johansson 0 0 0
02/21/08 VERPL Michelle Walter 0 0 0
02/23/08 VERPL Michelle Walter 4 3 7
02/26/08 VERPL Monitoring concelled- bad weather
02/28/08 VERPL Tait Johansson 0 1 1
03/01/08 VERPL Tait Johansson 0 0 1
03/06/08 VERPL Tait Johansson 0 1 1
03/09/08 VERPL Jim Jaffee, Laura Jaffee 0 2 2
03/11/08 VERPL Allen Kurtz, Nannette Orr 0 1 1
03/15/08 VERPL Tait Johansson 0 1 1
03/18/08 VERPL Nannette Orr, Ted Raymond, ER 0 2 2
03/20/08 VERPL Tait Johansson 0 1 1
03/22/08 VERPL Tait Johansson 0 1 1
03/25/08 VERPL Tait Johansson 0 1 1
03/27/08 VERPL Nannette Orr, Michelle Walter 0 1 1
03/29/08 VERPL Tait Johansson 0 2 2
 
 

    Iona Island

    Iona Island is a partially forested peninsula extending northeast into the Hudson River in Bear
Mountain State Park in the town of Stony Point, Rockland county, New York. It was monitored from a
scenic pulloff on Rt. 6 on the other side (the west side) of the Hudson from Iona Island. Iona Island
was apparently not consistently used as a Bald Eagle roost site this year, and may not have been used
at all.

     This roost averaged 0.00 roosting eagles in 3 monitoring visits, all in January 2008.
 
 
Iona Island
Date Location Observer(s) Total imms. Total ads. Total eagles
01/10/08 IONA Tait Johansson, Nannette Orr, Michelle Walter 0 0 0
01/17/08 IONA Allen Kurtz 0 0 0
01/22/08 IONA Tait Johansson 0 0 0
 
 




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Graphic Representations of Data
Fig. 1: Total eagles at Croton Dam (CD) compared to total eagles at George’s Island (GI)

                 Eagles at Croton Dam and Georges Island

                  50
                  45
                  40
                  35
   # of eagles




                  30
                                                                                                                       Croton Dam
                  25
                                                                                                                       George 's Island
                  20
                  15
                  10

                   5
                   0
                 12/16/200 12/26/200   1/5/2008   1/15/2008 1/25/2008 2/4/2008     2/14/2008 2/24/2008   3/5/2008
                     7         7
                                                              Date




   This graph compares total roosting eagle numbers at Croton Dam with those at George’s Island.
Higher eagle numbers at Croton Dam are apparent, especially later in the season.




 Fig. 2: Immatures vs. adults at Croton Dam

                                                   Immatures vs Matures at Croton Dam

                  30

                  25

                  20
   # of eagles




                                                                                                                         immatures #
                  15
                                                                                                                         matures #

                  10

                   5


                   0
                 12/16/200 12/26/200   1/5/2008   1/15/2008 1/25/2008   2/4/2008    2/14/2008 2/24/2008    3/5/2008
                     7         7
                                                               Date




   This graph compares numbers of immature eagles roosting at Croton Dam with numbers of adults
roosting there. Immature numbers fluctuated more widely than those of adults, perhaps indicating
greater adult roost site fidelity (see Bielfelt’s suggestion that this is the case in Bielfelt and Hannan
2007). Still, numbers of immatures and adults seemed to track each other fairly closely at this site, in
contrast to George’s Island (see Fig. 3 below).




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Fig. 3: Immatures vs. adults at George’s Island


                                             Immatures vs Matures at George's Island

                   14

                   12

                   10
    # of eagles




                    8
                                                                                                                         immatures #
                                                                                                                         matures #
                    6

                    4

                    2

                    0
                  12/16/200 12/26/200   1/5/2008   1/15/2008 1/25/2008   2/4/2008   2/14/2008 2/24/2008   3/5/2008
                      7         7

                                                               Date

 
 
  This graph, comparing numbers of immatures versus adults at George’s Island, shows fairly
consistently lower numbers of immatures compared to adults, unlike the numbers at Croton Dam.


  No similar relationships were visible in the data collected at any of the other sites, perhaps because
monitoring started later at these sites, and as a result, not as many data were collected.




Eagle Nests

    There were two active eagle nests visible from roost monitoring sites during the monitoring
period. Observations were taken during roost monitoring of any eagle activity and behavior
seemingly associated with either nest.



New Croton Dam Nest

Monitored from New Croton Dam, 1/1/08-3/29/08
Located on northwest shore of Croton Reservoir

    This nest, also occupied last year (Bielfelt 2007) appeared to be occupied by two adult-plumaged
eagles, likely the same pair as nested at this location last year. Possible breeding-related activity was
first noted around the nest on 1/31/08, when an adult Bald Eagle and a 4th year birds were noted
perched on the nest together during regular roost monitoring from the dam. On 2/7/08, two adults were
observed in the nest vicinity, one of them on the nest, apparently arranging nest material. On 2/16/08, a
bird appeared to be incubating for the first time. This nest was partially concealed behind tree
branches, and it was often difficult for observers to see what was happening around it clearly.
However, the pair continued to frequent the nest area at least until the end of roost monitoring on
3/29/08, and on that date, a bird was on the nest for a significant time, and appeared to still be
incubating.




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Stony Point Nest

Monitored from 1/22/08- 3/29/08 from small park in Verplanck
Located near lighthouse on Stony Point, Stony Point State Park, town of Stony Point, Rockland
County

   This nest was newly built this year, and appeared to be occupied by a pair of adult-plumaged
eagles. At least two other younger eagles, recognized by their individually distinctive plumages,
seemed associated with, or at least very interested in, the nest. One of the two, a 4th-year bird, even
added a stick to the nest on 1/22/08, and a 2nd or 3rd year bird was observed on 2/2/08 on the nest
arranging nest material. As the monitoring period went on, the younger birds stopped being seen in
the immediate area of the nest, and the two adults were the only eagles seen there. An adult bird was
seen incubating on 2/23/08, and the bird seemed to still be incubating on 3/29/08, when roost
monitoring at this site ended.




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Conclusion

   As in last year’s project, data collected in 2008 found no relationship between ice cover and
numbers of eagles. Perhaps more surprisingly, nor did our data show an inverse relationship
between temperature and number of eagles, as was found last year. Bielfelt and Hannan (2007)
speculate that the relationship found last year may have been due to eagles using secondary roost sites
on colder days, or perhaps eagles feeding later on cold days, and returning to roost in the dark, when
they cannot be detected. With more data collected this year than last, over a much longer period, the
lack of such a relationship this year indicates that last year’s result may just have been due to the fact
that all data that year were collected from late February to mid- March, a time of year when rising
temperatures coincide with increased eagle migration out of the area.

    As with last year’s data, numbers of immatures at both Croton Dam and at George’s Island
fluctuated more than numbers of adults, in line with the possibility mentioned by Bielfelt and
Hannan (2007) that adults may be more roost-specific than immatures. And at both George’s Island
and Croton Dam, there was an inverse relationship between the total number of eagles at each site on
a given day, strongly suggesting that there is some interchange between these two sites.

   The second season of Bedford Audubon’s Winter Eagle Monitoring Project saw a significant
increase over last year in the amount and scope of data collected on the area’s roosting eagles. This
project should continue in the future: the past two years’ close monitoring of these roosts has revealed
large numbers of eagles using them, but in numbers that can fluctuate significantly even over the
course of several days. These sudden fluctuations may well have had the effect of masking the true
extent of the area’s importance for wintering eagles, if past, less frequent surveys happened to occur
on “off days”. Frequent monitoring of these sites is therefore necessary. This charismatic bird merits
continuing careful attention to its numbers and habitats in this region.




Acknowledgements

  First of all, I’d like to thank my dedicated monitoring volunteers, without whom this project would
truly have been impossible: Joan Becker, Peter Becker, Margaret Freifeld, Walter Fowler, Jaqueline
Fowler, Tony Ianniello, Jim Jaffe, Laura Jaffe, Elaine Kellogg, Allen Kurtz, Denise Lee, Ken Mirman,
Nannette Orr (for both monitoring and data entry help), Helle Raheem, Omar Raheem, Ted Raymond,
Jeanne Waful, and Michelle Walter. Your efforts are greatly appreciated.

   Thanks also to Brian Bielfelt and John Hannan for their initial outline of the project and advice on
how to proceed, and to the DEP police for their willing and helpful cooperation. Thanks as well to
Connor Hershkowitz who produced the graphs for this report. Last but not least, thanks to Tony
Ianniello for his support and patience during the writing of this report, especially his patience.




Sources
   Bielfelt, Brian, and Hannan, John. Monitoring of Wintering Eagles in Westchester County 2007.

 Burger, Michael F., and Liner, Jillian M. Important Bird Areas of New York. 2005 Audubon
New York.

   Nye, Peter. New York State Bald Eagle Report 2007.




Bedfforrd Audubon Sociiiettty 35 Todd Road Katttonah NY 10536
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