Gone grebing August 5, 2012Posted by Bob Lewis in Birding
By Bob Lewis
Grebes have some of the most spectacular courtship displays of any bird, and to top it off, they are doting parents, carrying their young aboard their backs as they explore their marshy habitats. There are seven species of grebes in North America, and we are lucky to have four breeding near us in northern California, providing great birding and photographic experiences.
My first grebe event this year was with a Pied-billed Grebe family in Sierra Valley. A pair had built their floating nest in a small ephemeral pond near the road, and had successfully hatched a group of young. Normally these birds lay about six eggs, and there appeared to be six striped young competing for space aboard mom.
The youngsters are, at first, feathery puffballs unable to dive, due to the air entrained in their down, so the parents fish up crayfish and insect nymphs to feed them.
They carefully hand a morsel to the chick, which then usually drops it into the water and stares at the parent. The parent patiently dives down and fetches it back up, and the process repeats until the chick finally figures out how to swallow the delicacy. At the first hint of danger, the young hop aboard one of the parents, who cover them with their wings. Both parents build the nest, incubate the eggs, and raise the young.
Species two was a surprise for me, a pair of Eared Grebes at Hayward Shoreline, in brackish water in a marshy area with channels running through it. Eared Grebes generally have three eggs. This pair had two fuzzy chicks, which they were feeding as fast as they could — diving, bringing up small pond creatures, and stuffing them in the chick about every 5–10 seconds.
The Alameda County Breeding Bird Atlas notes that the third nesting record of this species in the county occurred in 1999. Since that time, nesting increased dramatically at Hayward Marsh, and in July 2005 there were over 200 Eared Grebes present. The size of the colony has fluctuated in recent years. Although these birds are colonial nesters, I only saw one pair.
I was too late to see the courtship displays of the Eared Grebe, which include a variety of behaviors named by ornithologists as the Cat Posture, Bouncy Dive, Ghostly Penguin, Penguin Dance and Habit-Preening. Each step in the courtship strengthens a pair bond, which lasts throughout the year.
Having seen two of our species, I was eager to observe the largest grebes in the area, Western and Clark’s Grebes. A trip to Clear Lake in mid-July was a true safari, on a pontoon boat to the nesting colony. About 150 birds were engaged in nest building, mating, courting, incubating and calling, creating a spectacular scene. Here I got to observe most of the courtship displays of these large grebes, centered on a series of behaviors called a Rushing Ceremony.
The Rushing Ceremony can include several males or a male-female pair. One of its stages is Ratchet-pointing, where the head is held low, with a raised crest and bill pointing toward the other bird.
In the Rushing stage, two or more birds turn to one side and lunge — bringing their bodies completely out of the water — and then run across the water’s surface. (See the photo at the top of this post.)
If two males Rush, they follow with Barging, a slow, stately progression across the surface, about two-thirds out of the water. Both Clark’s and Western Grebes have similar displays, with the only difference being their Advertising call, which initiates the process.
We also watched a Weed Ceremony, where a bonded pair follows Rushing with neck stretching and then weed diving, both bringing up pond weeds and raising them in the air together. All this activity builds a strong pair bond, resulting in mating, egg-laying, and raising two to three chicks.
Tags: Bay Area birds, bird courtship, Clark's grebe, courtship behavior, Eared Grebe, Grebe courtship, grebes, Pie-billed Grebe, Western Grebe.