Unexpected visitors: White pelicans of Colo.
special to the daily
I saw four white pelicans while rowing on Dillon Reservoir recently. They are actually not an unusual sight, although many people are surprised we have pelicans in Colorado. Last year I saw hundreds on Antero Reservoir. There were so many on a far shore, I thought it was snow. But when I rowed closer, I saw they were packed tightly in one area, many on the shore and many on land. It turns out this is a popular nesting area. Most people think of pelicans in Florida, but those are brown pelicans, and the American white pelican is quite different. They are a spectacular site on the reservoirs and lakes of Colorado. A nonbreeding, semi-permanent population spends the summer at San Luis Lake, which has the spectacular Great Sand Dunes in the background. We saw them when we rowed our double there in April.
They are large, snow-white, 50-70 inches long with black wing tips that can span up to 9 feet. Their orange feet are webbed not only between the four front toes but also between the second toe and the inwardly directed back toe. They live about 12-14 years. Unlike the brown pelican that dives into the water after fish, white pelicans have wide, flat bills with big orange pouches, and they scoop food while swimming. They can strain about 4 pounds of fish each day. They fish in cooperative groups forming a line or half circle and drive the fish into shallow water by beating their wings on the surface. When the fish are trapped in the shallows, they scoop them up in their pouched bills. Pelicans can hold as much as 3 gallons of water in their bill, and when they scoop up the fish they tilt their heads back, draining out the water, and then swallow the fish. Young pelicans feed by sticking their bills into their parents’ throat pouch to retrieve digested food.
Pelicans breed in large, dense colonies. Both sexes prominently display their bright orange bills during courtship rituals that include bowing and strutting. The male displays a fibrous bump on the upper part of the beak, a very distinct and a unique characteristic of the white pelican. They build a nest by making a shallow depression on the bare ground, and then they rim the nest with gravel, soil or plants. They lay two to three large, chalky-white eggs, and both parents incubate the eggs with their feet for about a month. When the chicks first hatch, they are blind and bald, but by 10 days they will grow thick white down. The “first hatched” of the chicks competes with the younger one for food and often the younger chick dies: survival of the fittest. The young stay in the nest for two to three weeks and then join other young in a “pod” until they are able to fly: teenagers hanging out! In late August or early September, before the freeze-up, they migrate mainly to the Gulf of Mexico coast for the winter to return the following spring, to Colorado to nest. Yikes – I hope the oil spill is cleaned up by then.
American white pelicans are protected under the Migratory Bird Treaty Act. Habitat loss caused by humans is the biggest threat to successful nesting, and this includes changing water levels due to irrigation and recreational use. Disturbance of breeding sites by boaters and fishermen, or industrial activity may cause birds to abandon an entire nesting colony, leaving eggs and young chicks to be trampled or exposed to harsh weather and predators. Go check out these spectacular birds in a paddle or row boat, but leave your motor boat behind.
Breckenridge resident Dr. Joanne Stolen is a former professor of microbiology from Rutgers now teaching classes at CMC. Her scientific interests are in emerging infectious diseases and environmental pollution.
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