[Tweeters] Re: cormorant sizes

Mike Patterson celata at pacifier.com
Tue Apr 17 20:36:08 PDT 2007


Sibley just pulled from the least accurate source...


>From Birds of North America online:


Pelagic Cormorant-
Males heavier than females. In Alaska samples, males average
2,034.0 g (range 1,816–2,440, n = 9) and females 1,702.0 g
(range 1,475–2,043, n = 5; Palmer 1962). However, in recent
sample from Gulf of Alaska, males averaged 1,750.0 g ± 160 SD
(range 1,600–2,100 g, n = 10) and females 1,531.4 g ± 124.8 SD
(range 1,450–1,770, n = 7; T. van Pelt pers. comm.). Scott
(1973) reports mean body mass (sexes not given) in Oregon of
1,626.2 g ± 101.6 SD (range 1,371–1,936, n = 5).

Double-crested Cormorant
Regional differences are large and no data are available from
the West coast and Alaska, where largest birds occur. Mean mass
of small southeastern birds is scarcely half that of northern
and western birds and the extremes span almost a threefold range
(1 to 3 kg). All samples collected in breeding season with the
exception of those from Mississippi. From New Mexico (Watson et
al. 1991): male, mean 2,453 g (range 2,200–2,750, n = 15);
female 2,056 g (range 1,750–2,400, n = 17). From Quebec (Bédard
et al. 1995b): male 2,089 ± 5.32 SE (n = 763); female 1,831 ± 7.17 SE
(n = 375). From Florida (Owre 1967): male 1,758 (range 1,327–2079,
n = 6): female 1,535 (range 1,391–1,665, n = 5). From Bahamas
(Watson et al. 1991): male 1,270 (n = 1); female 1,112 (range
1,036–1,175, n = 3). From Mississippi (in winter, Glahn and
McCoy 1995): male 2,498 ± 16 SD (range 2,000–3,000, n = 160);
female 2,162 ± 29.8 SD (range 1,650–2,600, n = 41). For additional
data, see Marshall and Erickson 1945 (Minnesota), Kury 1968 (Maine),
Hartman 1961 (Florida)

--
Mike Patterson
Astoria, OR
celata at pacifier.com

Dusty Book of the Month: _The Hawks of North America_
http://www.surfbirds.com/blogs/mbalame/archives/004483.html



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