Conservation Science and Stewardship at Audubon Canyon Ranch ARDEIDTHE 2 017 Egret telemetry study Fire ecology High-tech trapping for mountain lions Archaeology and zooarchaeology at Toms Point ❚2 Ardeid (Ar-DEE-id), N., refers to any member of the family Ardeidae, which includes herons, egrets, and bitterns. THE ARDEID 2017 In this issue The Movement Ecology of Egrets: Studying top predators to understand landscape habitat linkages by Scott Jennings page 1 The Foundation: California fire ecology by Sasha Berleman page 4 Toms Point Archaeology: Investigating Native American history at Tomales Bay by Tsim D. Schneider and Lee M. Panich page 7 Toms Point Zooarchaeology: Archaeological faunas shed light on the diets of past Toms Point residents by Anneke Janzen, Amanda Hill, and Tsim D. Schneider page 10 Walk Through to a New Era: Electronic walk-through cage for mountain lions by Quinton Martins and Neil Martin page 13 Cover: Great Egret preening. Creative Commons photo. Ardeid masthead: Great Blue Heron ink wash painting by Claudia Chapline. Above: Sus scrofa (wild pig, or boar) is amply represented in zooarchaeological remains at Toms Point. See page 10. The Ardeid is published annually by Audubon Canyon Ranch as an offering to ACR members, interested supporters, and volunteers who contribute to ACR Conservation Science, Stewardship, and Education programs To learn more about this program and how to support Audubon Canyon Ranch, please contact the Cypress Grove Research Center (cgrc@egret org or 415 663 8203) or ACR’s headquarters (acr@egret org or 415 868 9244) www.egret.org Managing Editor, John Kelly Layout design by Claire Peaslee Printed on recycled paper ©2017 Audubon Canyon Ranch Audubon Canyon Ranch protects our natural and human communities through land preservation, nature education, and conservation science. u Martin­ Griffin Preserve tCypress Grove Research Center tBouverie Preserve tModini Mayacamas Preserves ❚ ■❚ 2017 1 Studying top predators to understand landscape habitat linkages The Movement Ecology of Egrets by Scott Jennings Great Egret stands tarsus-deep on the edge colonies where they nest, and to Herons and egrets are ubiquitous in wetlands Aof a tidal slough, still and silent, seeming to measure the relationships between across the Bay Area and have served as iconic melt in and out of the cold February morning how they use habitats and how symbols of wetland conservation for over a fog Its long yellow bill stabs into the water, successfully they raise their young century As generalist top predators, they exert comes up with nothing but drops of water, then This is a fundamental pursuit of an emerging top-down influence on the structure of lower strikes again and this time snatches a wriggling field of research termed “movement ecology”- trophic levels, altering the abundance and distri- stickleback Having gotten its fill for breakfast the science of linking the why, where, when, and bution of multiple prey species and, in turn, the (or perhaps not), the egret croaks at something how of animal movements to the ecological and effects of their prey on other species (Huang et in the sky, then spreads its wings and takes evolutionary consequences of their behavior al 2015) Food-web connections involving top flight, disappearing into the rising mist (Nathan et al 2008) A greater understanding predators are important elements of healthy Where did this egret go? Why did it take of how individual movement and behavior are ecosystems and may influence rates of carbon flight now? Will it come back to this tidal slough related to survival and reproductive success will cycling (Schmitz et al 2014) Studying how tomorrow morning, or will it instead go else- provide a valuable new context to our long-term herons and egrets move across the landscape where to forage in a flooded pasture? Will this research on heron and egret nesting abundances to select and use habitats is critical to under- egret’s foraging behavior today and tomorrow across the Bay Area This expansion of our standing their ecological requirements and, in allow it to raise more young this spring than the research will lead to new insights into how these addition, their role as top predators in sustaining rest of the birds in its colony? How do the habi- beautiful birds depend on the varied wetland the richness of life in wetland ecosystems tats where this bird forages influence how long it conditions found throughout this urbanized lives? ACR has initiated an exciting new research region Research plan endeavor, the Heron and Egret Telemetry Project, Expanding ACR’s heron and egret research to answer questions such as these Movement ecology of predators to include GPS telemetry will allow us to answer We are using tiny, lightweight, solar-powered guides wetland conservation questions about these species’ ecological needs GPS tags (Figure 1) to record detailed informa- that are unanswerable using other methods tion about Great Egret movement and behavior Wetlands are the focus of growing atten- The tags we’ve selected to use in our study These tags will allow us to track individual birds tion from scientists and the public for their collect GPS locations and accelerometry data from the wetlands where they forage to the value as wildlife habitat and for the range of ecosystem services they provide for humans and send the information wirelessly back to us These services include flood mitigation, removal Accelerometers collect data on three-dimen- of pollutants travelling between rivers and sional movement that can be used to estimate oceans, buffering the effects of rising sea levels the energy costs of particular behaviors Thus, and increased storm intensity, and aesthetic the tags provide data on where birds go and benefits (Horwitz et al 2012, Scholte et al about what they do when they get there 2016) The San Francisco Estuary is the largest A key advantage in using GPS telemetry to wetland ecosystem in the western United study animal movement and habitat use is that States and provides essential habitat for diverse it avoids the bias that may be associated with wildlife, including large proportions of popula- field researchers observing individual animals tions of migratory and resident bird species in the field Rather than choosing when and (San Francisco Estuary Partnership 2015) where to observe animals, a researcher can use This estuary is a complex, broadly urbanized GPS tracking to intensively sample behavior and landscape, with a range of conditions (ecological habitat use, and then apply analytical methods processes, wildlife values, human land use, to let the animal movements themselves define recreation, etc ) affected by altered hydrologic the spatial and temporal scales of the investiga- Figure 1. A solar-powered GPS telemetry tag used patterns and by widespread restoration and tion Another benefit of using GPS tags is that to generate three-dimensional data on Great Egret conservation efforts (Cohen 2000) they generate a tremendous amount of data, movements, postures and behaviors. measuring animal locations and behavior far ❚ 2 The Ardeid ❚■ more frequently and over much larger land- they forage We will also join collabora- scapes than field observers can These extensive tive investigations with similar studies data will allow us to answer numerous ques- in the Midwest and along the East tions in several broad areas We will begin with Coast, to reveal how regional popula- descriptive analyses of movement, habitat use, tions of herons and egrets differ in their and energetics This information will provide a movements, behavior, and environ- foundation for more complex analyses that link mental requirements individual movements and behaviors to survival and reproductive performance and, ultimately, A nationwide collaboration to population dynamics Our investigation will This is an ambitious project and we be structured around the following five lines of have a tremendous amount to learn, inquiry but we are not embarking on this new 1 Landscape movement and habitat use We research alone ACR is the newest will describe and quantify how individual partner in an exciting—now nation- egrets move across the landscape and wide—science-based education project the environmental factors that influence called “1000 Herons,” which integrates their movement and habitat use This will the cutting-edge science of GPS telem- provide far greater detail about the lives of etry with the unique opportunities for egrets than previously known conservation education and outreach this method provides Key partners in 2 Energy balance We will investigate this collaboration are Dr John Brzorad and describe individual patterns of (Lenoir-Rhyne University, North energy intake and expenditure across Carolina), Dr Alan Maccarone (Friends the landscape We will generate maps of University, Kansas), Danielle D’Auria the “energy landscape” of these birds to (Maine Department of Inland Fisheries show how the temporal and spatial costs and Wildlife), and the U S Forest of movement relate to the benefits of Service’s Northern Research Station in foraging in different areas and habitats the eastern United States 3 Survival probability We will quantify the Drs Brzorad and Maccarone trav- relationships between egret survival and elled to California in early June 2017 their movement patterns, habitat use, and to teach us the egret capture method energy expenditure they developed and how to safely attach the GPS tags We use padded foot-hold 4 Reproductive success We will quantify the traps, modified to minimize any risk of relationships between egret reproductive injury to the birds, placed in shallow success (nest survival, number of fledged water in egret foraging habitat We chicks) and their movement patterns, use decoys—lawn flamingoes painted habitat use, and energy expenditure white!—to attract these gregarious Figure 2. Location data for our first three tagged birds during two 5 Population correlates of individual behavior foragers from the surrounding area, weeks in June, 2017.