I had my camera set up and focused on something else landside, when I heard a weird rasping noise on the water behind my back. A pair of Clark’s Grebes were engaged in a courtship ritual. They bobbed and weaved in harmony, dove under together, emerged and resumed, and performed a sudden burst of racing on top of the water together. If matters progressed beyond dancing, I did not observe it. After their dance, they separated a short distance and took up preening followed by napping. A closely related Western Grebe watched from nearby.
Wikipedia says about Clarks’ reproduction:
Clark’s grebes appear to have semi-monogamous behavior, staying with a single mate, but possibly only for a single season as far as known. Unpaired males far outnumber the females. Males, while they stay with their mate until at least a few weeks after the hatching of their young, will have several sexual partners in their lifetime. It is less known if pairs will eventually mate again in the future. There are two courtship ceremonies that are performed before selection and mating take place: the “rushing ceremony” and the “weed ceremony”. They entail a sequence of performances and advertisements/dances with the partner, or presenting the partner with a bundle of weeds and performing a different set of dances, respectively. As there are fewer females than males, the final decision of whether or not mating occurs depends on the females. Therefore, there is a level of sexual selection within the species. These courtships take place during spring migration and shortly after arriving on the breeding grounds.https://en.wikipedia.org/wiki/Clark%27s_grebe