[CT Birds] Turkey Vultures on Connecticut CBCs

Linda & Steve Broker ls.broker at cox.net
Sun Dec 20 23:11:54 EST 2009


Paul Carrier raised an interesting question about winter roost sites  
for Turkey Vultures and Black Vultures in Connecticut and suggested  
that Turkey Vultures are more likely to use coastal sites while Black  
Vultures are more likely to be found inland.  I've gone to my CBC  
spreadsheets to seek some data pertaining to this question.  Shown  
below are a table of CBC results for Turkey Vultures each year since  
1950-51 (arranged for the six northern counts, five mid-state counts,  
and six coastal counts, and also the yearly statewide totals) and  
some comments on how Turkey Vultures have been distributed in the  
state during these early winter censuses.  There is much more  
information to mine from the CBC data, but at least this is a start.   
(If the columns of numbers get hashed up in transit to the listserv,  
I'll fix them tomorrow.)
Steve Broker (Cheshire)

Records of Turkey Vulture and Black Vulture on Connecticut Christmas  
Bird Counts, 1950-51 through 2008-09.

The following Connecticut Christmas Bird Count data are for the  
period 1950-51 through 2008-09.  It is likely that a few Turkey  
Vultures were observed on Connecticut CBCs prior to 1950-51, but they  
do not occur in this analysis.  CW stands for Count Week (the count  
period).

Among coastal counts, New Haven had one Turkey Vulture on the 1950-51  
CBC.  First records for other coastal counts were:  Greenwich- 
Stamford, 1954-55; New London, 1977-78; Old Lyme-Saybrook, 1978-79;  
Stratford-Milford, 1991-92; Westport, 1975-76.  Greenwich-Stamford  
leads all coastal counts with a total of 936 Turkey Vultures during  
this period, followed by New London (835 TV), Westport (826), Old  
Lyme-Saybrook (597), New Haven (259), and Stratford-Milford (63).   
The top three totals of Turkey Vultures for each of these coastal  
counts occurred since the 2000-01 CBC, with the exception of 107  
Turkey Vultures at Old Lyme-Saybrook in 1984-85 (2nd highest total)  
and 78 Turkey Vultures at Westport in 1996-97 (3rd highest total).   
Highest totals for any single coastal count have been 170 TVs at New  
London (2004-05), 157 TVs at Old Lyme-Saybrook (2004-05), and 118 TVs  
at New London (2007-08).  The sixty-year total for all coastal counts  
is 3516 Turkey Vultures.

The first occurrence of Turkey Vulture on a mid-state count was in  
1969-70 at Pawling, NY-Hidden Valley, CT.  First occurrences  
elsewhere were:  Quinnipiac Valley, 1971-72; Woodbury-Roxbury,  
1976-77; Salmon River, 1981-82; Oxford, 1986-87.  The mid-state (and  
statewide) leader for Turkey Vultures is Oxford with a total of 1029,  
followed by Woodbury-Roxbury (818 TV), Quinnipiac Valley (356 TV),  
Pawling-Hidden Valley (246 TV), and Salmon River (95 TV).  Oxford had  
170 Turkey Vultures in 2006-07, 164 in 2007-08, and 159 in 2008-09).   
Interestingly, high counts occurred during the late 1970s to late  
1980s on Pawling, Salmon River, and Woodbury-Roxbury CBCs.  The sixty- 
year total for all mid-state counts is 2544 Turkey Vultures.

Hartford recorded the first Turkey Vulture among northern counts with  
one on the 1958-59 CBC.  Lakeville-Sharon recorded one CW in 1972-73,  
followed by Litchfield Hills (1979-80), Storrs (1983-84), Edwin Way  
Teale-Trail Wood (1986-87), and Barkhamsted (2001-02).  Barkhamsted’s  
lone Turkey Vulture record is a CW observation.  Storrs leads all  
northern counts with 337 Turkey Vultures during this time period,  
followed by Hartford (172 TV), Trail Wood (72 TV), Litchfield Hills  
(40), Lakeville-Sharon (19), and Barkhamsted (CW).  The single  
highest northern count was 83 Turkey Vultures at Hartford on the  
2008-09 CBC, while Storrs had 71 in 2006-07.  Peak totals occurred  
from the mid-1970s to the early and late 1980s in Lakeville-Sharon  
and Litchfield Hills.  Hartford and Storrs have had their highest  
totals mostly since 2003-04.  The sixty-year total for all northern  
counts is 640 Turkey Vultures.

 From the Christmas Bird Count data, one can draw a number of general  
conclusions.  Here are several:
(1)  Turkey Vultures were rare in early winter Connecticut prior to  
1975-76.

(2)  There were significant increases in Turkey Vultures beginning in  
1975-76, 1984-85, 1997-98, and especially in the last five to eight  
years.

(3)  Northern, Mid-state, and coastal regions of the state all have  
seen fairly steady and significant increases in Turkey Vultures  
during the past sixty Christmas Bird Count seasons.  Turkey Vultures  
were most abundant in the middle of the state up until 1990 or 1991,  
but coastal areas have become favored winter homes of Turkey Vultures  
since then.  Coastal counts have recorded twice as many Turkey  
Vultures as have mid-state counts in the last ten years.

(4)  The greatest concentrations of Turkey Vultures through the state  
have been in the northern counts of Hartford and Storrs, the mid- 
state counts of Woodbury-Roxbury and Oxford, and the coastal counts  
of Greenwich-Stamford, Westport, and New London.

(5)  It would be interesting to draw further inferences based on such  
factors as:  the timing of Turkey Vulture migration into the state  
from New York and further south; the presence of landfills in the  
state and their closing and capping; climatic differences between  
inland and coastal regions of the state; geographic factors within  
the state; potential distinctions between “natural” range extension  
and human-induced climate change.


Turkey Vultures on Connecticut CBCs

CBC Year            Northern            Mid-State             
Coastal            Statewide
1950-51            0                        0                         
1                        1
1951-52            0                        0                         
0                        0
1952-53            0                        0                         
0                        0
1953-54            0                        0                         
0                        0
1954-55            0                        0                         
3                        3
1955-56            0                        0                         
0                        0
1956-57            0                        0                         
0                        0
1957-58            0                        0                         
0                        0
1958-59            0                        0                         
CW                        CW
1959-60            1                        0                         
0                        1
1960-61            0                        0                         
0                        0
1961-62            0                        0                         
0                        0
1962-63            0                        0                         
0                        0
1963-64            0                        0                         
0                        0
1964-65            0                        0                         
0                        0
1965-66            0                        0                         
1                        1
1966-67            0                        0                         
0                        0
1967-68            0                        0                         
1                        1
1968-69            0                        0                         
0                        0
1969-70            0                        4                         
0                        4
1970-71            0                        0                         
0                        0
1971-72            0                        3                         
0                        3
1972-73            CW                        0                         
0                        CW
1973-74            CW                        0                         
0                        CW
1974-75            0                        CW                         
0                        CW
1975-76            16                        3                         
CW                        19
1976-77            3                        8                         
0                        11
1977-78            0                        55                         
CW                        55
1978-79            0                        3                         
5                        8
1979-80            6                        9                         
3                        18
1980-81            0                        16                         
13                        29
1981-82            4                        9                         
5                        18
1982-83            CW                         
40                        19                        59
1983-84            CW                         
35                        15                        50
1984-85            2                        35                         
108                        145
1985-86            0                        63                         
38                        101
1986-87            3                        90                         
36                        129
1987-88            1                        56                         
16                        73
1988-89            1                        48                         
26                        75
1989-90            16                         
99                        34                        149
1990-91            2                         
102                        51                        155
1991-92            10                         
26                        43                        79
1992-93            3                        91                         
73                        167
1993-94            2                        39                         
52                        93
1994-95            18                         
20                        121                        159
1995-96            6                        16                         
70                        92
1996-97            CW                         
24                        130                        154
1997-98            26                         
73                        124                        223
1998-99            19                         
124                        116                        259
1999-00            46                         
235                        115                        396
2000-01            31                         
142                        94                        267
2001-02            45                         
145                        220                        410
2002-03            16                         
72                        131                        219
2003-04            73                         
36                        185                        294
2004-05            49                         
145                        432                        626
2005-06            23                         
66                        357                        446
2006-07            112                         
270                        369                        751
2007-08            13                         
173                        283                        469
2008-09            93                         
169                        226                        488

Total                        640                         
2544                        3516                        6700


More information about the CTBirds mailing list