The Peninsula Watershed is studded with tall evergreen trees and often enshrouded in fog. Rainfall is abundant, sustaining massive Douglas firs, oaks, and laurels. Moss and lichens cling to branches and add to the lushness of this forest.
This is prime nesting habitat for the marbled murrelet, a seabird related to puffins and murres. While murrelets typically spend their days foraging for fish in the ocean, breeding adults fly from the sea to the canopy of an old-growth forest, miles from the ocean. Here they find nesting locations free of land predators, while it remains relatively close to a steady supply of small fish and shrimp.
Why build a nest when you have a cushion of moss? Each nesting season, a pair of murrelets incubate a single egg directly on a broad moss-covered branch high above the ground. Both parents care for the nestling. Once fledged, or able to fly, the young are thought to fly directly from the nest to the ocean.
The marbled murrelet is a threatened species. Populations have declined due to logging of old-growth forests, oil spills, and drowning in gill nets used for commercial fishing. San Francisco Public Utilities Commission staff monitor murrelet populations every year and ensure watershed operations and maintenance activities avoid disturbing nesting murrelets during the breeding season.
Touch the egg replica. Why is it widest in the middle? What do you notice about the end points?
The egg’s oval shape adds stability and reduces breakage. The blunt, rounded ends help keep the egg in place on a narrow, moss-covered tree limb.