Thursday, May 23, 2013

Wilson's Phalarope

Wilson’s Phalarope Facts

A large flock of Wilson’s Phalaropes has been at the Refuge for several weeks, to the enjoyment of the Refuge visitors.  Here are some facts about Wilson’s Phalarope, from Audubon  and the NationalZoo/Smithsonian Park websites:

Wilson’s Phalarope, Phalaropus tricolor,  is named after the great early American ornithologist, Alexander Wilson , and is the only one of the three phalarope species confined to the New World.

Wilson's Phalarope  is a slender, delicately built shorebird with a small head, and thin, pointed bill; medium-sized shorebird averaging 2.1 ounces in weight and 8.5 inches in length, with pointed wings that span 17 inches.

Females are substantially larger and can weigh as much as 40% more than males.

In winter, both sexes have grey-white plumage.

Breeding females (photo below) -  colorful, with a gray cap, white eyebrow, and dark crimson mask that extends from the bill to the back of the head and then swoops down the nape toward the back. The throat is white; a rusty wash colors the neck and chest, otherwise whitish below and grey above.

Breeding males (photo below) - pale grey above and whitish below, with a light rusty wash on the nape of the neck.

Winter range – from Peru  to the tip of South America
Breeding range -  Great Plains of North America

Feeding – a number of Refuge visitors have commented on the Phalarope’s spinning behavior during feeding.  Note circular ripples in the photo of the female phalarope.  “Like other phalaropes, the Wilson's often spins in the water, at speeds of up to 60 turns per minute. The purpose of this whirling behavior may be to churn the muddy bottom, excite small aquatic creatures, and condense them in the swirls, where they can be picked off the surface. Wilson's phalaropes consume flies, beetles, brine shrimp, and other tiny marine creatures."

Reproduction – sexual roles are reversed with the female displaying bright plumage and aggressively  courting males They often mate with more than one male, have more than one nest and, after egg-laying, they leave their families to the sole care of the males.

The female lays four eggs; incubation time is 18 – 27 days. The young are fully feathered and  can walk, swim, and feed independently within an hour after hatching, but require brooding to keep them warm.

After the breeding season , Wilson’s Phalaropes are one of the few birds to undergo a post-breeding, molt migration, traveling to large western lakes in the US to molt and build up fat reserves for the 54 hours flight to South America.   According to  The Sibley Guide to Bird Life and Behavior, they can gain up to 55% of their body mass at this time; some become too fat to walk, and have to "take off" swimming.  

Photos taken at Hagerman NWR by Dick Malnory

1 comment:

  1. I love this bird. I saw my first one when on a tram tour. Observed the spinning too. A great bird to introduce children to.