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Southern Resident and Bigg’s (Transient) killer whales/orcas



CWR staff took the UAV video above of J, K, and L pods in Haro Strait during 2023 UAV Encounter #9 (August 17).

Researchers from the Center for Whale Research and the University of Exeter are using Unmanned Aerial Vehicles (UAVs)/Drones to study the behavior of the Southern Resident and Bigg’s (Transient) orcas from a new perspective.
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Until now, research on killer whale social networks has relied on seeing the whales when they surface and recording which whales are together. Looking down into the water from a drone allowed us to see details such as contact between individual whales. Our findings show that even within the resident killer whales’ tight-knit groups, they prefer to interact with specific individuals. It’s like when your mom takes you to a party as a kid: you didn’t choose the party, but you can still choose who to hang out with once you’re there.

— CWR’s Dr. Michael Weiss, lead author of a CWR-University of Exeter study, talks about the research results in Age and sex influence social interactions, but not associations, within a killer whale pod, published in the journal Proceedings of the Royal Society B.

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2023 UAV Encounter #15 (September 14); from the Encounter Summary: “Within half an hour, the team observed their first capture of the day, and J47 and J57 chased a fish very close to shore off Pile Point. J47 made the final capture, and shared half the fish with his younger brother. The same pair made another capture just ten minutes later.”


Southern Resident


CWR’s Unmanned Aerial Vehicle:

DJI Matrice 600 Pro.

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CWR’s Unmanned Aerial Vehicle:

DJI Phantom 4 RTK v2.

Since 1976, the Center for Whale Research has been conducting observation-based studies of orcas in the Salish Sea. The unique dataset produced by this work has informed conservation efforts in both the USA and Canada and helped us understand these animals’ complex lives, revealing factors that influence survival, reproduction, social structure, and the evolution of this species unique life history. 

Our research has established that a lack of salmon is the primary factor constraining the recovery of the Southern Resident killer whale (SRKW) population. However, we still have many gaps in our knowledge.


The most recent NOAA/NMFS Priority Report for the SRKW in 2015 outlined two priority questions for future research:

1) What is causing decreased SRKW reproduction? 

2) What is causing increased SRKW mortality? 


Understanding individual and group (social) behavior is key to answering both of these questions. Our research objective for the UAV activities will directly address this knowledge gap by recording how individual behavior and the behavior of social groups relate to survival and reproductive success.


Nearly all our knowledge of Southern Resident orca behavior is based on surface observations from boats and shore. However, orcas spend almost all their time submerged and out of sight; this means that we have not been able to document most of these whales’ lives in any detail. Using a UAV/drone gives us the opportunity to get above the whales and look down into their world. We can position our drone, a DJI Matrice 600, hundreds of feet above the whales, and monitor their movements and behaviors as they move through their world without interfering in their activity. Under the right conditions, the UAV can see to a depth of 10 meters underwater, and a lot of behavior happens in this surface zone.


In 2018, we had numerous successful drone flights, documenting a variety of behaviors, from food searching to coordinated travel and foraging to socializing. This data is helping us to understand better social behavior and its consequences in this population, as well as foraging strategies and foraging efficiency and how this relates to survival and reproduction. With this information, we will be able to make future predictions for the health and survival of these amazing animals and inform strategies to recover this endangered population.​

In 2019, the CWR-University of Exeter SRKW Aerial Observation Study expanded with funding from the National Environmental Research Council in the United Kingdom. The study became part of a large international project to look at how family life influences rates of aging. The overall project has three subprojects. The first is to develop new theory for how family dynamics influence the rates of aging and changes in behavior across the lifespan invertebrate populations (particularly looking at sex differences). The second project tests the behavioral predictions of this work in the Southern Resident orcas using drone observations. Finally, researchers from the University of Exeter will undertake comparative projects that will assemble data across social mammals to test the generality of the theory developed.

Published scientific/academic papers as a consequence of the Aerial Observation Study research.

Weiss, M. N., Franks, D. W., Giles, D. A., Youngstrom, S., Wasser, S. K., Balcomb, K. C., Ellifrit, D. K., Domenici, P., Cant, M. A., Ellis, S., Nielsen, M. L. K., Grimes, C., and Croft, D. P. (2021). Age and sex influence social interactions, but not associations, within a killer whale pod. Proceedings of the Royal Society B, Volume 288 Issue 1953. Full Text.

CWR-University of Exeter RESEARCH

Latest published paper reveals new aspects of the SRKWs unique social structure.

Observing orcas from the air gives a novel look into their social structure.

The Southern Resident killer whales are well known for their complex societies, with whales living in family units referred to as matrilines, which are part of larger units referred to as pods. This June 2021 study from the Center for Whale Research (CWR) and the University of Exeter, Age and sex influence social interactions, but not associations, within a killer whale pod, reveals new aspects of this unique social structure. Read the CWR Blog about about this research.

July 2021 published paper provides new evidence of menopause in Biggs (Transient) killer whales.

The Bigg’s (Transient) killer whale component of the Aerial Observation Study is done in collaboration with University of Exeter Ph.D. student Mia Nielsen. Nielsen led a team of researchers to complete: A long postreproductive life span is a shared trait among genetically distinct killer whale populations, published in July 2021 in Ecology and Evolution. 


Read Nielsen’s July 2021 CWR Blog: New evidence of menopause in Bigg’s Transient killer whales.

We were amazed to see how much contact there is between whales—how tactile they are. By adding drones to our toolkit, we have been able to dive into the social lives of these animals as never before.

— CWR and University of Exeter’s Dr. Darren Croft

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The Evolution of Sex Differences in Mammalian Social Life Histories

CWRs Executive Director and Professor of Animal Behaviour at the University of Exeter,
Dr. Darren Croft,  
summarizes the Aerial Observation Study project:

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A still image of SRKWs captured from CWR’s drone video footage taken during 2023 UAV Encounter #5 (July 1).

Understanding why social behavior and life histories have diverged between the sexes in long-lived social mammals, sometimes to an extreme degree, is a key objective in the biological, medical and social sciences. Our research team proposes that differences between the sexes in how males and females interact with related individuals across the lifespan is a major force driving the evolution of sex differences in both social behavior and life history. 


In social species, related individuals (kin) often live together in close-knit family groups and individuals can influence the survival and reproductive success of their relatives both by their behavior (cooperative and competitive) and reproductive decisions (if an individual reproduces it will use resources that may negatively impact on the survival and reproductive success of kin). Such interactions between kin are a strong evolutionary force, with individuals gaining indirect benefits (through the genes they share with relatives) by increasing the survival and reproductive success of their kin. For example, kin selection can favor individual strategies that increase the reproductive success of kin, even if this comes at a cost to an individual’s own survival and reproductive success. The opportunity for evolution to be shaped by kin selection is dependent on how and when related individuals interact. 


Our pilot work suggests that in many species males and females experience very different patterns of local relatedness across their lifespans (kinship dynamics) due to patterns of dispersal and mating. For example, for some species such as Southern Resident killer whales females are predicted to become more related to their local group with age whereas males, in contrast, are predicted to become less related. 


We hypothesize that sex differences in kinship dynamics will be a major force driving the evolution of sex differences in both (i) social behavior and (ii) life history.

We will determine the role of kinship dynamics in driving the evolution of sex differences in social behavior and life history evolution using a combination of theoretical modeling and empirical data analysis. We will develop a general theory of kinship dynamics and develop new models to predict both the patterns of kinship dynamics and their consequences for the evolution of social life histories in both males and females. Our model will make predictions for patterns of helping and harming in social groups including both behavioral traits (cooperation and conflict) and reproductive traits (e.g., age at first or last reproduction).


We will provide the first test of the behavioral predictions of our new theory by collecting new data on patterns of helping (e.g., babysitting and food sharing) and harming (aggression) in Southern Resident killer whales using unmanned aerial vehicles (drones). Resident killer whales are ideally suited to testing the behavioral predictions of the model - they are predicted to have extreme sex differences in patterns of kinship dynamics and have unexplained sex differences in life history. We will test the life history predictions of the theoretical framework by comparing patterns of sex differences in life history evolution (e.g. patterns of growth, age at first reproduction, age at last reproduction, reproductive investment and longevity) across social mammals which will allow us to determine the role of kinship dynamics in driving the divergence of life histories between the sexes.


Our CWR-University of Exeter research will further our understanding of the evolution of sex differences in life history and social behavior and will leave a new theoretical framework that will provide testable predictions for the evolution of behavior and life-history traits in social mammals, including humans.​

Evoluntion of Sex
Studies Team
Aerial Observation Research

The scientists and others
behind the research

Drone Data Collection

Dr. Michael Weiss - CWR Research Director and Drone Pilot (FAA licensed commercial UAS pilot)

Other Project Team Members

Dr. Darren CroftCWR Executive Director and Professor of Animal Behaviour at the University of Exeter

Dr. Sam Ellis -  Postdoctoral researcher, University of Exeter

Dr. Dan Franks - Reader, Department of Biology, University of York

Mike Cant - Professor of Evolutionary Biology, University of Exeter 

Rufus Johnstone - Professor, Department of Zoology, University of Cambridge 

Dr. Tom Currie - Associate Professor in Cultural Evolution, University of Exeter

Paolo Domenici - National Research Council, Oristano, Italy

Federica Spina - PhD Research Student, University of Pisa

Charli Grimes - PhD Research Student, University of Exeter

Rachel John - Masters Research Student, University of Exeter 

2023 UAV Encounter #9 (August 17) with J, K, and L pods.

DJI Matrice 600 Pro
About the Center for Whale Research’s UAVs:
DJI Matrice 600 Pro
DJI Phantom 4 RTK v2

The research team uses different models of Unmanned Aerial Vehicles (UAV) for their SRKW and Bigg's orca studies. The DJI Matrice 600 Pro is used for shore-based flights. It is the larger of the two UAVs; it can be seen from a considerable distance when flying from land. On the CWR research vessel, the team uses a DJI Phantom 4 RTK v2, the smaller of the two DJI models. It’s easily retrieved by the pilot when flying from the research boat. Both UAVs have outstanding designed-in reliability.

Does the UAV/Drone
disturb the whales?

The UAV is a non-invasive method for recording behavior, and there is minimal potential for noise disturbance to the orcas. Recent work has shown that the noise produced by UAVs couples poorly into the water and could only be quantified above the background noise of the recording sites at a one-meter depth when flying at altitudes below 10 meters. All of our flights are conducted well above this height (typically 60 meters), and it is likely that the whales are not even aware of the presence of the UAV during our research flights.

PLUS UAV/Drone Pilot
Training and Certification.

Before undertaking any flights for the Aerial Observation Study, the permit required the pilots to complete a minimum of 25 hours of flying time and 50 flights with the DJI Matrice 600 Pro to establish its reliability and suitability for the research. The drones have accumulated over 400 hours of flying over more than 1000 research flights. A spotter visually tracks the drone on each flight to ensure safe operation and maintain visual line-of-sight as required by the permit.

Does drone disturb the whales

More Video and Photographs

Visit our YouTube channel

2023 UAV Encounter #16 (October 4): Footage of the T49As hunting but without T49A1 or T49A2 present.

2022 UAV Encounter #15 (September 28) of J pod in Haro Strait.

This footage is part of 651 minutes of drone video filmed over ten days in 2021. Read Dr. Weiss’s June 17, 2021 BLOG, Observing orcas from the air gives a novel look into their social structure, for insight into CWR’s scientists’ expanded knowledge of orcas from studying aerial video of the whales.

In this July 2021 UAV/drone recording, a group of Bigg’s Transient orcas is traveling and socializing along the shoreline. There are both adults and younger individuals in the group, identified by their size differences.