A great egret careens above the Bolinas Lagoon, intent on landing in the crown of a thick pine grove. Extending its long, spindly legs, it flaps and squawks while groping for purchase in the branches. Neighboring egrets raise a ruckus, and the new arrival clambers onto its nest, where three rapacious chicks await.
Down on the wharf, biologist Scott Jennings zeroes in on this scene with a spotting scope. The nest is one of hundreds in a study of egret and heron populations across northern San Francisco Bay counties. Scott’s best chance to see how well the chicks are doing is when they rise up and climb all over each other, vying for a meal from deep inside their parent’s beak. “I don’t envy an egret or heron when it’s feeding its young,” he said.
Scott does feel lucky to have his job description, however. Since spring, he has worked as an avian ecologist for Audubon Canyon Ranch, headquartered just across the lagoon. He is already designing innovative research to inform A.C.R.’s own stewardship and to share with their conservation partners.
The nonprofit’s citizen scientists monitor heron and egret colonies throughout the North Bay, but the Bolinas colony receives special attention, because about 20 pairs of great egrets began breeding here in 2014. That followed several years of steep declines in their nests at Audubon Canyon, meaning that some or all of the egrets Scott is monitoring likely moved here from A.C.R. He uses the same protocol developed decades ago by Helen Pratt, a naturalist and self-made biologist who led an effort to learn the outcome, year-in and year-out, of every visible nest at the preserve.
The birds’ recent departure from A.C.R. was mostly due to bald eagles scaring the egrets off their nests, but it’s quite normal for breeding egrets and herons to shift locales over time. Some colonies increase or appear while others shrink or are abandoned.
“Our real focus is how well these populations are doing on a regional scale over the long term,” Scott said. “With data spanning decades, we’re able to see beyond the steep fluctuations that can occur in a shorter period like five years. The patterns tell us a lot about the health of wetland ecosystems, where these birds are top predators. The good news is that great blue herons and great egrets are stable in our region.”
Understanding ecosystems is the big attraction for Scott. He caught this scientific bug during five seasons he spent as a field biologist in Antarctica. While helping gather data on Adélie penguins in their breeding colonies, he “started really wanting to know how you could find the meaningful story within all those measurements.”
“Ecology is complex and there can be confounding factors, so a big part of figuring out what the data say is learning statistics,” he said. “That was a lot of my motivation for going back to school to work on a master’s degree: to learn more statistical tricks.”
For his thesis study, Scott correlated the weight gain and likely survival of Adélie chicks that were fed different kinds of food. “There were meaningful details, but not a whole lot of surprises!” Scott laughed. “That’s a generality about ecology: we’re quantifying all this stuff that—if you just spend time out in nature, observing—you probably already know. After turning the knowledge into numbers, a language that nobody can understand, we then have to translate it back into everyday English to communicate our results.”
On a serious note, he added, “For conservation to be effective, it’s essential that we base management decisions on quantified knowledge of how natural systems work.”
Scott’s work in conservation science is imbued with a big dose of love for the wild. He grew up the son of a park ranger and lived until age 10 in the Sinkyone Wilderness. His passion for Sierra Nevada backpacking nearly led him to pursue a career in mountain guiding. But an internship with Point Blue (then Point Reyes Bird Observatory) captured him for keeps. “Working and living with really great people, while learning the scientific method—I just wanted to keep doing that,” he said.
After all his subsequent travels and training, Scott’s morning on Wharf Road represents a homecoming of sorts. Townspeople here have come to know him, and they stop by to compare notes on the heron and egret colony. A boy and his father walking toward the beach ask how long until the chicks fly away. Local birders confirm the continuing presence of a double-crested cormorant nest, the first one known at this locale.
With his day’s data complete, Scott commutes back to his office at Cypress Grove Preserve, A.C.R.’s property in Marshall. The rack atop his truck may carry surfboards or else a canoe and kayak. On this early June morning, he detours up Terrace Avenue for a quick check on the surf to consider his after-work options—outdoors, where he prefers to be.
Claire Peaslee is a writer and naturalist who lives in Point Reyes Station.