Bald Eagle Census

Last Thursday, I participated in a survey of wild Bald Eagles along the Mississippi River.  

We departed from the Spirit of St. Louis Airport in Chesterfield in a Cessna 185 named the “Earth Angel.”  The plane was beautifully painted red and white, but the interior of the plane was significantly smaller than most cars.  We wore headphones to communicate over the hum of the plane’s engine.

The familiar landmarks in Chesterfield Valley seemed like pieces on a model train town as we flew overhead.  When we reached the Alton lock and dam on the Mississippi River, we began to count the Bald Eagles we observed below.  

Bale Eagles perched in trees along the river

Even though the plane flew as slow and low as possible, the eagles still appeared only slightly larger than the head of a pin.  Most of the eagles perched on the branches of large cottonwood trees growing on the very edge of the river.  We observed a few eagles in flight.  I was most amazed to spot eagles perched on ice blocks floating in the river.  They balanced on the edges of the ice and peered over into the water, waiting for an unlucky fish to swim past.  This sight reminded me how well eagles and other birds are protected from the cold temperatures by their feathers and the scales on their feet.

Bald Eagles perched on ice floes use another hunting technique 

As we spotted the Bald Eagles, Jeff Meshach, the Assistant Director of WBS and navigator of this flight, marked their location on a detailed map of the area.  We also noted whether the bird was a juvenile or adult, and whether it was perched, flying or standing on the ice.  In all, we counted 676 bald eagles.  The majority were adults perched in trees and were most heavily concentrated in the northern sections of our survey area.  Happily, the number of bald eagles in the survey has increased significantly over all the censuses done last year.

Submitted by Leah Sainz, World Bird Sanctuary Naturalist