[CT Birds] Shrike Question

[Linda & Steve Broker]

On Shrikes:

The Christmas Bird Count season, now defined as December 14 through  
January 5, represents a limited slice of early winter.  There  
obviously is a lot more that takes place during Connecticut's winter  
season than is represented by this three week period.  Nevertheless,  
it's interesting to look at the CBC data for shrike and see how the  
numbers play out over the course of the last half-century.

The huge shrike incursion referred to by Mark Szantyr undoubtedly was  
the winter of 1995-96, when a total of 67 Northern Shrikes was  
recorded on Connecticut Christmas Bird Counts.  This is far and away  
the biggest shrike incursion on record since 1950, at least as  
suggested by CBC data.  The winter of 1999-2000 ranks second for  
numbers of shrikes counted on Connecticut CBCs, with 24 total.   
During the current (2007-08) winter's CBCs, 16 Northern Shrikes were  
reported, the third highest total since 1950.  The only other double  
digit shrike year was 1978-79, when 14 Northern Shrikes were counted  
on Connecticut CBCs.

Dividing Connecticut's statewide CBC data into northern, mid-state,  
and coastal subtotals - that is, the 6 northern CBCs, 5 mid-state  
CBCs, and 7 coastal CBCs - the picture gets somewhat more  
interesting.  This winter, 12 of 16 Northern Shrikes were seen on  
northern counts and just 2 each were seen on mid-state and coastal  
counts.  We can reasonably call this a shrike incursion year, but it  
helps if you have been birding in the northern parts of the state  
(again, based only on CBC data).  The winters of 1978-79 and  
1999-2000 had somewhat more equal distribution of shrikes on CBCs  
throughout the state:  5 northern, 4 mid-state, and 5 coastal in  
1978-79; 12 northern, 7 mid-state, and 5 coastal in 1999-2000.  Most  
interestingly, the incursion year of 1995-96 had Northern Shrike  
found well-distributed throughout Connecticut, with 31 recorded on  
northern CBCs, 16 on mid-state CBCs, and 20 on coastal CBCs.  A  
statewide incursion, indeed!

Zeranski and Baptist (1990) states, "[d]uring the winters of  
1921-1922, 1926-1927, 1930-1931, and 1949-1950 large numbers [of  
Northern Shrikes] were reported in southern New England."  My Excel  
spreadsheets have not yet been extended back to the first half of the  
20th century, so I can't comment on these winters.  I'll leave it to  
others to use BirdSource on-line data to see what these CBC years  
were like.

The other half of the shrike equation in Connecticut is Loggerhead  
Shrike.  Remember them?  During the period 1950-51 through 1979-80,  
Connecticut CBCs recorded 41 Loggerhead Shrikes while counting 94  
Northern Shrikes during the same period.  From 1 to 4 Loggerhead  
Shrikes were seen in most years up to the earliest 1980s.  The last  
Loggerhead Shrike seen on a Connecticut CBC was on the New Haven  
Christmas Bird Count in mid-December 1984.  While I don't  
specifically remember, this may have been the bird that was hanging  
out at the Tire Pond in Hamden, edge of the Quinnipiac Marshes.  That  
bird I specifically remember.  It's the last Loggerhead Shrike I've  
seen in Connecticut.  Again from Zeranski and Baptist:  "[Loggerhead  
Shrike] decreased as a migrant and winter visitor in the 1970s and  
1980s, and its nesting range retreated westward to western New York  
state."

Steve Broker
Cheshire