Verification of Unusual
Rec. # 2010-31
|Scientific name:||Phalacrocorax brasilianus|
|Date:||August 15, 2010|
|Length of time observed:||20 min|
|Age:||1 ad, 2 juv|
|Location:||Bear River MBR, unit 6|
|Latilong:||60-70 m SE of N41deg25'22.2" W112deg05"39.6"|
|Distance to bird:||60-70m|
|Optical equipment:||8 x 42 binos; 85mm scope w/20-60x eyepiece|
|Weather:||Clear, sunny, temps in 90s|
|Light Conditions:||Full sun from behind right shoulder|
|Description: Size of bird:||About gull-sized w/different shape|
|(Description:) Basic Shape:||Elongated, especially neck and tail|
|(Description:) Overall Pattern:||Blackish iridescent (ad) dark brown (juv)|
|(Description:) Bill Type:||Fish snagging|
Field Marks and
Blackish iridescent. Strong white outline of gular pouch appearing like a V-shape. Dark lores. Two or three short white filoplumes on the sides of the head just behind the aft point of the gular. Same size as the two juveniles. Did not see length of tail in comparison to body, and forgot to assess the angle at which the rear point of the gular projected backwards.
The most thoroughly-studied bird. It was the only cormorant perched on a line of stones with a group of pelicans, and it looked shockingly small. Bird was dark brown with no tan tones on the neck and breast. Head tapered smoothly into neck with no bulkiness. Dark lores. Bill appeared smaller than what I expect for DCCO, although none available for direct comparison. Upper mandible entirely dark. Orange color of gular not Halloween-orange as seen in other DCCOs today. Weak orange color continued forward past gular and about halfway to distal end of the beak. Pale, poorly defined feathered border outlining gular pouch. Rear point of gular angled back more diagonally, rather than with a more vertical border where it met the lower cheek. When swimming, tail appeared to be about two-thirds the length of the body. In flight, lump at base of neck barely apparent. View of neck and tail projection beyond body (for proportion assessment) not good.
Second juvenile: Dark brown, same size as adult and the other juvenile when all three swam tightly together.
|Song or call & method of delivery:||None heard.|
One juvenile standing on a rock low to the water with a group of pelicans; the
two other cormorants not apparent at that time. Bird eventually flew a circle
around observers and landed in the water, and then was joined by the adult and
the other juvenile. The three swam in a tight trio for awhile, occasionally
diving, and then one of the juveniles chased the adult away.
One thing about the behavior of the cormorants is that I noticed a fair bit of 'give and take' between the adult and the juveniles before the adult left, with the adult lunging at the juveniles as well as vice versa. It certainly looked like it was a case of parent-offspring conflict over how long to continue feeding.
|Habitat:||Shallow alkaline marsh adjacent to Great Salt Lake.|
were they eliminated:
Not a Double-crested Cormorant: Adult would not have thick white outline to
gular pouch and short white filoplumes on the sides of the head. Would likely
have unfeathered orange lores and a stronger orange color to bill, lores, and
Juvenile DCCO: Would have unfeathered lores, gular and beak in a strong orange color, varying tan plumage on neck and breast.
Any age DCCO should also show a shorter tail, perhaps less than half the length of the body when swimming, and a more vertical border to the gular pouch where it meets the lower cheek, rather than diagonal and pointing backward sharply.
this & similar species:
|One juvenile, August 2009. Extensive with DCCO.|
|Description from:||From memory|
|Observer:||Kristin M. Purdy|
|Observer's address:||Ogden, Utah|
|Observer's e-mail address:||email@example.com|
|Other observers who independently identified this bird:||Jim Mountjoy|
|Date prepared:||August 15, 2010|