April 11, 2008

 

GREBES ON LAKE OROVILLE

 

Rex Burress

 

During the first part of April, Michael Hubbartt, State Parks Interpreter at Lake Oroville,

 

phoned me about a number or western grebes on the lake. During a Saturday morning nature walk, the group had watched a couple of young bald eagle make some passes at the grebes, rather messing up the onslaught, not that they were a serious menace since those trim white-necked targets are excellent divers and highly alert.

 

"What is the migratory pattern of those grebes?" Mike asked.

 

I conferred with Tim Ruckle of the Altacal Audubon of Chico, and he quizzed some members that generally thought them to be moving up from Mexico to spread out in northern lakes. It is known large numbers spend the summer at Klamath Lake, Eagle Lake and Clear Lake, nesting in the tules since they like the shallows. Petersonís map shows summer range across much of western U.S. and into lower Canada, where they again choose reedy lakes

 

Although there are six grebe species in the U.S. and 20 in the world, the western grebe (Aechmorphorus occidentalis) is famous for their mating dance, a rapid short foot-patter across the water with a pair side by side, bodies arched into an unbelievable upright stance. Evidently they donít hang around Lake Oroville long, as I know of no nesting pairs. The shoreline is too erratic with little vegetation. Birds have an eye toward such things.

 

I have seen western grebes up close after an oil spill in the Bay Area and International Bird Rescue was cleaning them. Their body feathers are more like fur, thick and tough, said to have been at one time in demand for wearing apparel since the thick skin could be fleshed like a pelt. What is striking is their vivid red eye set against the white feathers. They are also known for carrying the babes on their back, hiding them in the feathers for safety.

 

The bill is dagger-like, in comparison to the Pied-Billed Grebe, a dumpy little phantom of the shallows that slinks beneath the surface like a descending submarine, and sometimes emerges with just its head showing in floating plants. The short thick bill can handle a full-sized crayfish, which is swallowed whole in an extraordinary swallowing performance. We called the aquatic scroungers "hell-divers" on the Missouri farm, so quick were they to submerge.

 

The grebes are a ghostly clan, normally shy quiet birds, but at mating time even the little pied-bill resonates a loon-like piercing wail in the swamps totally unexpected, as well as other weird sounds. The floating nests are massive, partially attached to tules.

 

The pinnacle of diving birds, grebes live exclusively on water, even unable to walk on land due to the feet being at the back end like the motor on a boat.