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14 GREAT BLUE HERON
<br />in its favour. Protection of colony- sites, feeding
<br />grounds, and suitable winter habitats probably
<br />most important. Screening protects fish in ponds
<br />and hatcheries from this and other herons (Mott
<br />1978).
<br />APPEARANCE
<br />MOLTS AND PLUMAGES
<br />Juvenal plumage. Great Blue Heron: according
<br />to Palmer (1962) pushes out down so that chicks
<br />are well feathered by one third grown. Most of
<br />Basic I plumage of juvenile acquired in autumn
<br />and retained for > 1 yr.
<br />Basic I plumage. Slaty crown sometimes
<br />showing small white basally or totally white
<br />feathers, grayish rather than brownish neck, white
<br />sides of face, dark neck feathers, and narrow
<br />sometimes elongated mantle feathers. Cinnamon
<br />colored feather edging on wing coverts (RWB).
<br />Alternate I plumage. Acquired in first winter;
<br />characterized most notably by molt of new crown
<br />feathers.
<br />Basic II plumage. Worn by yearlings (13-24 mo
<br />or longer); gray or gray - streaked crown (i.e. not all
<br />white), blackish sides of crown, and short occipital
<br />plumes, elongated feathers on sides of neck and
<br />mantle but shorter than in adults, and black
<br />shoulder patch. Cinnamon feather edging on wing
<br />coverts sometimes present (RWB). Prebasic II molt
<br />of all feathers in summer or autumn, completed in
<br />autumn. Molt of throat plumes begins after eggs
<br />are laid (Apr -May), of flight feathers in Jun in
<br />British Columbia (RWB).
<br />Alternate II plumage. Second winter composed
<br />of at least new forehead, crown feathers, wing
<br />covert and some back feathers. Molts probably
<br />proceed distally among primaries, proximally in
<br />secondaries, and centripetally in rectrices, as in
<br />Grey Heron (A. cinerea; Milstein et a1.1970). Great
<br />White Heron: wholly white in all stages. Molt
<br />sequence probably similar to herodias (Bent 1926,
<br />Palmer 1962).
<br />Description. Juveniles (0-12 mo) brownish
<br />compared to adults; crowns are gray (may have 1
<br />cm'- white patch at 8 mo); no body plumes; rust -
<br />brown edging to back and wing coverts; upper
<br />maxillary is brownish, lower is yellowish. Yearlings
<br />(13-24 mo) resemble adults but have more gray on
<br />forehead and crown; rust -brown edges to wing
<br />coverts; plumes on breast are short or absent.
<br />Adults, Great Blue Heron: sexes similar, but
<br />males on average slightly larger than females
<br />(Table 1). Adults (> 24 mo) slaty-gray on wings,
<br />A. Poole, P. Stettenheim, and F. Gill, Editors
<br />The Birds of North America, No. 25, 1992
<br />back and sides of neck; primaries darker than rest
<br />of wing; black, white and rusty streaks on front of
<br />neck; sides black and rust, black patch near bend
<br />of folded wing; underparts streaked with black,
<br />white belly and under tail; face and crown white
<br />with wide black occipital bands terminating in
<br />usually 2 plumes; yellowish bill long and tapered;
<br />legs brownish or greenish; plumes extend from
<br />sides of neck, breast and over back; middle toe
<br />pectinated. 70% of adults in British Columbia can
<br />be sexed with 95% confidence using length of
<br />exposed culmen (Simpson 1984, Butler et a1.1990).
<br />BARE PARTS
<br />Breeding season. In Florida, bright orange or
<br />red bills, bright lime -green lores, bright red legs
<br />and feet and yellow iris (Meyerriecks 1960). In
<br />Minnesota and Texas, bills mostly yellow, bright
<br />cobalt -blue lores, reddish legs; irides deeper yellow
<br />(Mock 1976). British Columbia: bright yellow bills,
<br />blue-green lores, and greenish -yellow legs (RWB).
<br />Maryland: red bills, blue lores, reddish legs (Dolesh
<br />1984). Color fades soon after egg laying begins.
<br />Legs and bills "reddish" in Nova Scotia (Quinney
<br />and Smith 1979).
<br />Nonbreeding season. Great Blue and Great
<br />White in Florida have dull yellow bills, pale
<br />grayish -blue lores, and yellow irides; legs and feet
<br />yellowish -green in former, brownish or greenish-
<br />black in latter (Meyerriecks 1960). In British
<br />Columbia, bills dorsally yellowish -brown and
<br />ventrally dull yellow, lores pale grayish -blue, legs
<br />brownish - green, feet yellow - green, irides yellow
<br />(RWB).
<br />MEASUREMENTS
<br />Adult males slightly larger than adult females
<br />(Table 1). Little information on Great White Heron,
<br />suggesting similar to Great Blue (Palmer 1962).
<br />ACKNOWLEDGEMENTS
<br />I thank Darin Bennett, Ed Bruckner, Ian Moul,
<br />Max Partch, Bill Scharf and Marilyn Sigman for
<br />use of unpublished data, and Range Bayer and
<br />Peter Stettenheim for helpful comments on this
<br />manuscript. Bob Chandler wrote the section on
<br />fossil history, Fred Sheldon the section on
<br />systematics. The Christmas Bird Count database
<br />depends on input from volunteers across the
<br />continent. Cover photo by Arthur Morris.
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