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Wisconsin Natural Resources magazine

Wisconsin Natural Resources magazine

June 1999

Pelicans flock to the Mississippi River. © Ray Marinan and Mary Stefanski

Pelicans' feast

The once-scarce pouched birds now dine in greater numbers at the Mississippi River's bountiful table.

Ruth Nissen

Pelicans flock to the Mississippi River.

© Ray Marinan and Mary Stefanski

Pelican populations on the rise | On the nest

On a late August day a small flotilla, including two boats equipped for electrofishing and several flat-bottom boats, gathered near the mouth of Sommers Chute on the Mississippi River near La Crosse, Wis. Hungry for action, the wildlife and fishery biologists from the U.S. Fish and Wildlife Service and the U. S. Geological Survey waited in the boats for breakfast to begin.

On this particular morning, however, their companions had no appetite. The white pelicans they'd come to observe feeding left their loafing sites only under protest, when a fishing boat strayed too close. The big birds seemed to prefer dozing in the sun rather than eating, moving only occasionally to stretch.

"The biologists were working on a project to determine what kind of fish the pelicans were eating," says Eric Nelson, Wildlife Biologist on the Upper Mississippi River National Wildlife and Fish Refuge. "Sampling was scheduled for three different sites on the river that pelicans consistently had been using throughout the summer."

The project is just one facet of a larger study of how white pelicans are distributed and which property they use along the Upper Mississippi River. Formerly a rare sight on the river, the white pelican is now becoming a regular at the Upper Mississippi's grand buffet. If the pelicans had cooperated, the birds would have been flushed off the feeding area as soon as they had started eating. Biologists in the flat-bottom boats would have moved in to mark the boundaries of the site, and then the electrofishing crews would have stunned any fish in the area, counting, identifying species, and releasing the fish unharmed. (This plan had worked well the day before at Weaver Bottoms, a backwater of the Mississippi River near Wabasha, Minn.)

"This technique works because pelicans follow a well-laid plan when feeding," says Mary Stefanski, Refuge Operations Specialist with the Fish and Wildlife Service's La Crosse District. "Large groups of the birds form a squadron, herding the schools of small fish into shallow water where the pelicans circle them and in a frenzied confusion of pounding wings feed on the buffet." An adult pelican on the average can eat three pounds of fish a day. Gizzard shad and emerald shiners seem to be the most available fish in the pelican's feeding areas on the river.

Pelican populations on the rise

Last year during August, more than 1,000 pelicans were counted on the Mississippi River from Alma, Wis. to Dubuque, Iowa. "During the last 10 years, pelican numbers have been increasing along the Mississippi River," says Stefanski. "There were a few stragglers (one to three birds) sighted about 10 years ago. Then about five years ago the numbers started to increase to the levels we see today." Flocks of the fish eaters can be seen riding the thermals – gliding in a circular pattern while gaining altitude – lounging on sandbars in the river, or joining in the frenzy that accompanies group fishing.

"The pelicans spotted on the Mississippi River are either on the way to nesting sites, or are too young or too old to reproduce," Stefanski says. Pelicans reach breeding age between three and four years old. The birds old enough to reproduce develop nuptial tubercles or large ridges on the tops of their bills, and grow ornamental plumes or dark feathers on the tops of their heads. "The tubercles are not known to serve any function but folklore says they are an aphrodisiac," Stefanski says. "The tubercles fall off the adults once the young have hatched."

Resting on the nest.

© Ray Marinan and Mary Stefanski
Resting on the nest. © Ray Marinan and Mary Stefanski

Pelicans nest in colonies on islands and peninsulas. The closest nesting colony to the Mississippi River is Marsh Lake at Lac Qui Parle in western Minnesota. In 1998, this colony had approximately 15,000 adult pelicans, 5,000 young pelicans, several hundred cormorants, ring-billed gulls and a few great blue herons and cattle egrets.

The largest of Minnesota's three pelican breeding colonies, the Marsh Lake colony, was discovered in 1968. It has been studied as part of a banding program since 1972. In 25 years, more than 27,000 pelicans have been fitted with a size 9 U.S. Fish and Wildlife Service metal bird band around one leg (mallards are fitted with a size 6). Band returns from this project have yielded important information on pelican migration and mortality. Pelicans from Marsh Lake winter in Mexico, Florida, Texas and other states along the Gulf of Mexico, and at several points in between.

Band recoveries indicate that pelicans live a long time: To date, the oldest pelican from the colony is 14, but 30-year-old pelicans have been found. If the birds can avoid being shot, flying into power lines, or becoming entangled in fishing line – the major causes of pelican mortality – they can live for many years.

On the nest

Pelicans build nests on the ground by hollowing out a small depression and then gathering dead vegetation to use as lining around the nest by pulling it in with their beaks. Their nests are placed about two neck lengths apart, just far enough to avoid being pecked by a neighbor while sitting on the nest.

Pelicans usually lay two eggs. Because they lack a brood patch – a patch of bare skin on the belly used by other birds to incubate eggs – pelicans incubate the eggs by grasping one egg in each foot.

The newly hatched chicks are orange-colored, featherless, helpless and homely. They are also very small (about three ounces), but they grow quickly. Chicks eat partially digested food obtained by shoving their heads into a parent's pouch. (Pelicans don't actually carry live fish in their pouches to their young.) By the time they are one month old, the young birds begin leaving the nests and joining with other young pelicans in "pods" or gangs. The pods become a flurry of feathers when the adults return with food. The young are fed regurgitated fish until they are capable of flying and feeding on their own, at about 10 weeks. In September, young and old leave the nesting grounds and head for the coast.

An increasing number of pelicans spend the summer on the Mississippi River.

© Ray Marinan and Mary Stefanski
An increasing number of pelicans spend the summer on the Mississippi River. © Ray Marinan and Mary Stefanski

The future for pelicans in Wisconsin is promising. Historically, it's likely that pelicans once nested on an island in Pelican Lake, southeast of Rhinelander in Oneida County. However no documented breeding populations occurred in the state until 1994 when white pelicans attempted to nest unsuccessfully on Cat Island in lower Green Bay. Pelicans had been regularly seen in the Green Bay area since the mid 1980s before the attempts to nest on this small offshore island formerly used by the U.S. Army Corps of Engineers as a dredge spoil site.

"The second year there were nine nests and only one young was produced," says Tom Erdman, Curator at the Richter Museum of Natural History at the UW-Green Bay. The number of nests increased dramatically in the subsequent two years and by 1998, about 165 nests were found on the island, Erdman says. "During a visit later in 1998 at least 200 young pelicans were counted." Conditions in the lower bay are favorable for pelicans with ample supplies of gizzard shad and a limited number of herring gulls, so the pelicans can fish in peace.

Will the pelicans ever nest on the Mississippi River? "With an increasing number of pelicans spending the summer on the river, nesting could be possible if an island with minimal human disturbance is available to the birds," Stefanski says.

For more information, visit the Upper Mississippi River National Wildlife and Fish Refuge.

Ruth Nissen is a biologist with DNR's Mississippi River-Lower St.Croix Team stationed in La Crosse.