Summit Outside: White pelicans are peculiar
September 2, 2012
We have been seeing white pelicans on Dillon Reservoir recently. They do not spend as much time on the reservoir as they do on Antero Reservoir in Fairplay, but they seem to stop by and spend some time here every year, especially in the early and latter part of the summer.
We saw about six clustered together on a small rock island that had emerged from our low water levels. They probably stopped by to check out the local fish cuisine en route south.
I had the good luck to spend quite a bit of time observing white pelican behavior when we stayed at a lakeside property in Klamath Falls, Ore., in June. They are amazingly gregarious. A whole group will huddle together on a log or a small rocky island. Sometimes two will intertwine necks and sit snuggled together for hours on end.
Early in the morning we saw them flying in a perfect line formation from their evening roost on a large fallen log to the feeding grounds on the lake. They would land and swim along the shore quietly like large ghosts on parade.
Often we would spot another group flying in to join them from another part of the lake. An apparent leader of the group would stop cruising the bank and the group would form a semicircle against a bank and move in closer toward shore. They would be herding fish into shallower waters against the bank. All of a sudden there would be a great deal of splashing and ducking of their beaks into the water as the feeding frenzy began. This could go on for maybe five to 10 minutes and then they would resume cruising along the bank of the lake looking to find more fish to corral for breakfast. This is called “cooperative herding” by ornithologists. Apparently they will also form a circle in open waters and trap fish, though I did not observe this behavior on Klamath Lake.
White pelicans are some of the largest birds in North America and despite this they are amazingly graceful in flight. It is a spectacular sight to see a large group fly in formation. They hold their head close to and aligned with their body by a downward bend in the neck.
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White pelicans can reach a length of 62 inches, have a wing span of 11 feet and weight over 16 lbs.
They are white with black wing tips, a huge bill which can reach 11 inches and a leathery pouch. The pelican’s pouch serves simply as a scoop. As the pelican pushes its bill underwater, the lower bill bows out, creating a large pouch which fills with water and fish, but as it lifts its head, the pouch contracts, forcing out water, but retaining the fish.
Pelicans have short legs and webbed feet allowing them to swim efficiently.
On Antero Reservoir there are colonies of white pelicans. When we rowed on the lake the far shore looked like there was snow on the banks, but as we got closer we realized there were hundreds of pelicans all clustered together.
Their roosting site is at the opposite end of where the two boat launch sites are on Antero. This is adjacent to range lands and there is no road access to these areas, so they are relatively secluded.
The pelican finds a mate for the season. Courtship consists of circular flights over the nesting site, and a variety of displays on the ground, including strutting, bowing and head swaying.
The nest is a shallow depression, the rim just sufficient to keep eggs and chicks from rolling out.
The female can lay from one to four eggs in a clutch. The young are cared for by both parents.
Unlike most birds, which warm their eggs with the skin of their breasts, pelicans incubate their eggs with their feet. They hold the eggs under the webs that stretches from the front toes to the hind toe, actually standing on the eggs to warm them. This peculiar incubation method made them especially vulnerable to the effects of DDT, which made the eggshells thin. The incubating parents frequently cracked their eggs.
The incubation stage lasts 29-36 days. The young are born naked and blind, but their eyes open within a day. They quickly develop blackish-brown down.
Parents regurgitate food for the young, onto the ground or their feet at first. As the chicks grow older the parents regurgitate the food to their own bill tip, and then only within their pouch, and finally only into their own throat.
The colony gathers in “pods” around 20-25 days after the eggs hatch. The young fledge at 65-75 days of age.
About 64 percent of young survive to adulthood, with sexual maturity attained at 3 to 4 years of age.
Great white pelicans have been exploited by humans throughout history. Their pouch was used to make tobacco bags, their skin is turned into leather and the guano used as fertilizer. The fat of young pelicans is converted into oils for traditional medicine in China and India. In Ethiopia, great white pelicans are hunted for their meat.
A wonderful bird is the pelican,
His bill will hold more than his belican,
He can take in his beak
Food enough for a week,
But I’m damned if I see how the helican.
(Limerick by Dixon Lanier Merritt in 1910)
Dr. Joanne Stolen is retired from teaching microbiology at Rutger University.