[CT Birds] Fox Sparrow

Clay Taylor ctaylor at att.net
Mon Mar 19 00:19:44 EDT 2007


Steve -

Excellent!   This is fun.

Even though we are up to our scopes in snow and ice on March 18, we should 
not forget that Nov '06 - mid January '07 were very warm and dry, and the 
half-hardy birds were in pretty good numbers for most CBCs.    Whether that 
means that the majority of the wintering Fox Sparrows were still north of us 
and we had the southern fringe (not likely) or that an average number were 
present in CT for such weather conditions is open to debate.    The animated 
maps of eBird show us that the Fox Sparrow movement is presently northward, 
and our storm has given us the sparrow equivalent of a "fallout".

Clay Taylor
Moodus, CT
ctaylor at att.net

PS - I will be traveling out of state from Tuesday through Sunday, so 
everybody get ready - something really GOOD will be arriving as soon as I 
leave.   Let's see, previous examples are the Pink-footed Geese, the 
Swallow-tailed Kite, the Solitaires, the Red-footed Falcon.......need I go 
on?

----- Original Message ----- 
From: "Linda & Steve Broker" <ls.broker at cox.net>
To: <ctbirds at lists.ctbirding.org>
Sent: Sunday, March 18, 2007 9:30 PM
Subject: Re: [CT Birds] Fox Sparrow


> Inspired by the two to three Fox Sparrows coming to my yard feeders
> daily since early March, and also by the steady stream of comments
> about Fox Sparrow, I've gone to my spreadsheets of Christmas Bird
> Count data for the period 1950-51 through 2006-07 to see what the CBC
> numbers show about this species in early winter.  Please note these
> caveats:
>
> (1)  The following numbers are raw data as published in Audubon Field
> Notes and American Birds and also as sent to me by Connecticut CBC
> compilers since the mid-1980s.  They have not been adjusted in accord
> with total party hours.  (Note that the BirdSource website contains
> historical data that frequently are rounded to tens.  This may not
> apply to Fox Sparrow, but it does apply to birds recorded in higher
> numbers.  The accurate numbers for counts occurring before National
> Audubon went to online data entry are found in the NAS publications
> mentioned above.)
>
> (2) Connecticut CBCs have ranged from 8 counts statewide in the 1950s
> and 1960s to the present total of 18 counts.
>
> (3) Total observers per year have ranged from under 100 in the 1950s
> to 900 or just over 1000 in some of the more recent years.
>
> (4) These data apply to the early winter period of ca. December 14
> through January 5.  They lump Fox Sparrow numbers across the state.
> I have breakdowns for each state CBC and also for the (current) 6
> northern counts, 5 mid-state counts, and 7 coastal counts for all 283
> bird species recorded on Connecticut CBCs during this time period.
>
> Here are the numbers for Fox Sparrow:
>
> Year Number Year Number Year Number
>
> 1950-51 12 1970-71 139 1990-91 44
> 1951-52 17 1971-72 131 1991-92 73
> 1952-53 65 1972-73 119 1992-93 74
> 1953-54 51 1973-74 99 1993-94 34
> 1954-55 14 1974-75 110 1994-95 43
> 1955-56 54 1975-76 101 1995-96 26
> 1956-57 27 1976-77 190 1996-97 84
> 1957-58 38 1977-78 124 1997-98 44
> 1958-59 127 1978-79 58 1998-99 127
> 1959-60 132 1979-80 55 1999-2000 123
> 1960-61 138 1980-81 145 2000-01 120
> 1961-62 86 1981-82 60 2001-02 198
> 1962-63 53 1982-83 117 2002-03 139
> 1963-64 208 1983-84 88 2003-04 142
> 1964-65 79 1984-85 77 2004-05 51
> 1965-66 153 1985-86 53 2005-06 170
> 1966-67 111 1986-87 28 2006-07 83
> 1967-68 202 1987-88 47
> 1968-69 256 1988-89 27
> 1969-70   339 1989-90 63
>
>
> If one ignores rigorous statistical analysis and just graphs out
> these numbers, the following emerges:
>
> (a) Fox Sparrow numbers fluctuate significantly from year to year,
> with increases of one to four years often followed by decreases of
> one to four years.
>
> (b) There is an overall trend of increasing numbers from 1950-51
> through 1969-1970 (20 year span), followed by decreasing numbers from
> 1969-70 through 1988-89 (20 years), followed by increasing numbers
> from 1988-89 through at least 2001-02 (14 years).
>
> (c) Of the 57 years shown here, 29 years had Fox Sparrow counts
> higher than the 2006-07 CBC total, and 27 years had counts lower than
> the 2006-07 total.  This past early winter is essentially the median
> for the past 57 years.
>
> (d) Major peaks in Fox Sparrow numbers on CBCs occurred in 1969-70
> (339 individuals reported!!) and 2001-02 (198 individuals reported).
> These numbers make the current number of 83 birds observed on our
> most recent CBCs pale in comparison.  Perhaps the next few years will
> continue this most recent upward trend.
>
> (e) Linking early winter Fox Sparrow numbers with late winter-early
> spring numbers may not mean a whole lot, but if the numbers fluctuate
> so widely in early winter for this species, it's not unreasonable to
> expect that they fluctuate in early spring as well, and perhaps not
> in parallel.  I'm reminded of the apparent disconnect between fall
> migrant American Kestrel numbers and the incredible plummeting of
> early winter kestrel numbers of the last twenty years.
>
> There's more to be gleaned from the above data, but this is as far as
> I'm going to take it.
>
> Steve Broker
> Cheshire
>
>
>
>
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