SNAP*Shot: Eared Grebes

What a surprise! On my morning walk around Cattail Lake there were six pair of Eared Grebes. I have only ever seen them in Yellowstone but here they are. I know they nest in colonies, so maybe six pair could be a colony? I’m so excited that we may have baby Grebes close to home this year! The young ride on their parent’s back for the first two weeks of their lives. What a sight that would be! Let’s see what a little research turns up.

Eared Grebes are small diving birds, about 12 inches long. They are typically gray with mottled underparts, a slightly crested black head with white neck and nape, and bright red eyes. However, in breeding season both sexes don golden ear feathers fanning out behind their red eyes with black neck and back, a great puffy crest on their head, and chestnut flanks. What a transformation!

Well, my hopes are dashed. Cattail Lake doesn’t have the right habitat for Grebe nests. Their nests are made of floating vegetation and mud, anchored to reeds. This nice clear lake appears a good stop over, but not a place to stay–darn. Also, the smallest colony, and small colonies are unusual, is about 15-25 pairs, not 6. With the correct habitat in a large lake, a colony may have thousands of nesting birds. Well, little 12-acre Cattail Lake doesn’t make the cut for nesting Grebes.

Eared Grebes are so fascinating and in many ways unique. They are the most abundant grebe in the world, but are not found everywhere. In the U.S. they are only found west of the Mississippi and are just migrant visitors in the Heartland states. Grebes are superb swimmers and divers. Their feet have three large lobed toes to aid in propulsion and steering in the water. Their legs are set far back on their bodies and their wings are small which aids them to efficiently propel themselves underwater. Having their legs so far back on their bodies, however, makes walking on land almost impossible. Eared Grebes breed in fresh water, but their fall staging areas and winter homes are in very salty habitats.

In the fall Eared Grebes gather in large numbers in staging areas, with the greatest numbers at Mono Lake and Great Salt Lake. Approximately 1.6 million birds visit Mono Lake alone, where they dive to feed on brine shrimp, plankton, and other invertebrates. During this time, the grebes more than double their weight. Their pectoral (chest) muscles shrink to the point where they become flightless, the digestive organs grow significantly, and great fat deposits accumulate. Before they can continue their migration the grebes need to fast, allowing the digestive organs to shrink to about one-fourth their peak size, and they exercise their wings allowing the heart and pectoral flight muscles to grow quickly to their maximum size. A cycle similar to this fall staging cycle happens three to six times every year for the Eared Grebe. Between 9 and 10 months each year this bird is flightless, the longest flightless period for any bird in the world capable of flight.

The Eared Grebe migrates only at night. This has caused disasters for them as they become confused by night-lighted areas reflecting off shiny or wet surfaces. In December 2011 about 5,000 grebes thought a wet Walmart parking lot in Cedar City, Utah, was a lake and crashed on it killing about 1,500 birds. In the past 10 years there have been over 175 disasters like this killing more than a thousand birds in each one.

Luckily most survive to continue to their fall staging areas then on to their winter homes in the southwestern United States and Mexico. But for now, let’s enjoy them on Cattail Lake!

Until next time, have fun exploring the uniqueness found in your neck of the woods!