Thesis Defense by Katie Harrington-July 11th

Seasonal time-energy allocation of an island-restricted Falconid, the Striated Caracara, using a low-cost, open-source inertial movement GPS logger

A Thesis Defense by Katie Harrington

Vertebrate Ecology Lab

Thursday, July 11th, 2019 at 12 pm

MLML Seminar Room

Katie began research on striated caracaras in 2015 and has since took over leadership of a long-term research site begun by Hawk Mountain Sanctuary in 2010. Along with overseeing and implementing the expansion of a banding program and educational outreach to farmers and schoolchildren in the islands, Katie’s research has focused on striated caracaras’ seasonal movements, feeding ecology, and energy use. Katie is currently collaborating with researchers in mainland South America to study the population genetics of striated caracaras within and beyond the Falklands, and to support and encourage research into their little-known populations in Chilean and Argentine Tierra del Fuego.


Thesis Abstract:

According to life history theory, animals should have adaptive strategies to cope with seasonal fluctuations in resource availability. However, the introduction of human settlements to natural landscapes can affect the spatial and temporal patterning of resources and disrupt the naturally occurring resource variation to which an animal is adapted. Human subsidies impact animal populations by affecting their density, population growth rate, and abundance. Research has shown that island species dependent on human subsidies are more prone to population declines and local extirpations. While population level effects are known, little research has been aimed at individual level behavior and energy allocation effects. Here, I investigate the time-energy allocation and activity budgets of striated caracaras (Phalcoboenus australis), a scavenging and predatory Falconid in the Falkland Islands, a highly seasonal and human-subsidized environment. I developed the Tapered Wings Logger, a low-cost, lightweight inertial movement GPS logger, and made the logger design available for researchers and applicable across many systems. I deployed the loggers on caracaras to examine seasonal differences in time-energy allocation and activity budgets. The acceleration data were used to calculate overall dynamic body acceleration (ODBA, gravitational g), a proxy for energy expenditure, and to estimate behavioral state using hidden Markov models. I combined the GPS data with ecological knowledge of the species and study sites to help validate model results. Additionally, I investigated space use with daily distances traveled and home range kernel density estimates. My results suggest that on a daily scale, caracaras overwintering at a farm settlement worked 20% harder than in summer (24-hr ODBA: winter 2848.07 ± 577.26 g; summer 2380.85 ± 435.65 g [x̄ ± SD]). During daytime, hourly ODBA rates were nearly two times higher in winter compared to summer (winter 239.50 ± 51.61 g; summer 127.92 ± 26.01 g). Caracaras exhibited more intense activity in winter, spending twice as long in the high activity state compared to summer (winter 99.0 ± 45.2 min, summer 44.1 ± 26.1 min). In addition, during winter, caracaras traveled greater cumulative daily distances (winter 23.75 ± 7.50 km, summer 10.94 ± 3.29 km) and daily ranges were 13 times larger (95% KDE: winter 8.34 ± 11.04 km2, summer 0.64 ± 0.49 km2). This study emphasizes that even with human subsidies to cope with seasonal food availability, caracaras work harder in winter than in summer to obtain enough energy to meet daily requirements. Many island-restricted species will likely face increased variation in resource availability in response to environmental change and human population expansion. I suggest conservation managers consider these results for how to target their efforts to maximize the benefit during a critical life stage of a near threatened species.

Thesis Defense by Heather Barrett-May 24th

The energetic cost of human disturbance on the southern sea otter (Enhydra lutris nereis)

A Thesis Defense by Heather Barrett

Vertebrate Ecology Lab

Friday, May 24th, 2019 at 4 pm

MLML Seminar Room

Heather Barrett is a master’s student under Dr. Gitte McDonald in the Vertebrate Ecology Lab. She graduated from the University of California Santa Cruz in 2009 with a B.S. in Ecology and Evolution and studied abroad in England, France, and Belize. Prior to her research at Moss Landing Marine Labs, Heather interned with the Monterey Bay Aquarium’s Sea Otter Research Program, worked abroad in education, managed data entry and fieldwork with California Department of Fish and Wildlife’s long-term biodiversity assessment in Northern California, and assisted with whale shark research in Mexico. Heather currently is a team member with Sea Otter Savvy and hopes to continue her work with research, science communication, and outreach.

Thesis Abstract:

With increased human populations and tourism in coastal areas, there is increased potential for disturbance of marine wildlife.  Impacts of disturbance are not well understood for many coastal species, such as the southern sea otter (Enhydra lutris nereis). Due to high metabolic rates, sea otters are at particular risk of increased energetic costs due to human disturbance. To investigate effects of disturbance, behavioral scans were conducted over three years to record sea otter activity in response to potential disturbance stimuli at three locations in California: Monterey, Moss Landing, Morro Bay. We developed a hidden Markov model to examine how activity varies as a function of location, time of day, group size, pup to adult ratio, habitat (kelp vs. open water), and occurrence of and proximity to potential disturbance stimuli. We combined our results with published estimates of activity-specific metabolic rates, translating changes in activity state into corresponding energetic costs. Our results indicate that the effects of disturbance stimuli on sea otter behavior are location specific, and vary non-linearly with distance from disturbance stimuli. Our model quantifies the distance-disturbance relationship, and calculates the distance at which the likelihood of disturbance is low: averaged across locations, there is <10% potential disturbance when stimuli are >54 meters away. We also estimate energetic costs(kJ) associated with various disturbance scenarios: for example, daily energy expenditure is expected to increase by 212.53kJ ± 15.75, 154.64kJ ± 13.84 and 62.54kJ ± 5, for Monterey, Moss Landing and Morro Bay, respectively, with six small-craft approaches of 20m for a 27.7kg male otter in kelp with 10 otters and a pup ratio of 0.25. Our analyses represent a novel approach for estimating behavioral responses and energetic costs of disturbance, thereby furthering our understanding of how human activities impact sea otters and providing a sound scientific basis for management.

Listen Up! Our grad students are doing some awesome outreach

Listen Up!

Brijonnay Madrigal is a student in the Vertebrate Ecology Lab who studies bioacoustics of Risso's Dolphins in the Monterey Bay.  To share her love and knowledge of the incredible sounds of marine mammals, Brijonnay has developed an outreach program in the Monterey Bay area. "Listen Up!" is an interactive program that teaches K-12 students about marine mammals, acoustics, sounds in the ocean, and conservation. The program has already reaches 10 elementary schools, 1 middle school, and 10 high schools in the area.


Alison Stimpert gives insight on government shutdown

January 11, 2019

MLML's Dr. Alison Stimpert talks about how the government shut down is affecting scientists in this NPR article.


Alison Stimpert, a marine biologist with California State University, writes, "Even though I am continuing to work, many of my collaborators (USGS, NOAA) are furloughed and projects we are working on together cannot move forward." She says that means "project planning meetings are being delayed, as well as permit applications for upcoming work."
Stimpert studies bioacoustics — "acoustic behavior and effects of noise on marine species," she explains — in waters off of California, Hawaii, Massachusetts, Alaska and Antarctica. She says that in some cases, the shutdown means she may have to reorganize some travel or wait to start a phase of research until collaborators can work. In other areas, it might have more serious implications: "We might miss an opportunity to deploy an instrument, which makes us miss collecting an entire season of data." And Stimpert says that if she or her collaborators have future federal funding delays, it could mean that "I can't purchase an instrument that I need, but might (and I am not alone in this) mean my other funding runs out and I can no longer fund my position, making me lose my benefits."

MLML’s Dr. Alison Stimpert co-authored recently published study on blue whale behavior

Dr. Alison Stimpert

Research Faculty member Dr. Alison Stimpert serves a co-author for a large collaborative study on blue whales that has revealed preferences in the direction (right vs left handedness) that the whales will roll during lunge feeding.  The study was published in Current Biology on November 20th, 2017 and featured in UCSC News, as well as The Guardian.  You can download the paper for free for 50 days here.