Dialect Use Within a Socially Fluid Group of Southern Resident Killer Whales, Orcinus Orca

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Master's Theses

Fall 12-2014

Dialect Use Within a Socially Fluid Group of Southern Resident Killer Whales, Orcinus orca

Courtney Elizabeth Smith University of Southern Mississippi

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The University of Southern Mississippi

DIALECT USE WITHIN A SOCIALLY FLUID GROUP OF

SOUTHERN RESIDENT KILLER WHALES, ORCINUS ORCA

Courtney Elizabeth Smith

A Thesis Submitted to the Graduate School of The University of Southern Mississippi in Partial Fulfillment of the Requirements for the Degree of Master of Arts

Approved:

Dr. Stan Kuczaj______Committee Chair

Dr. Alen Hajnal______

Dr. Sheree Watson______

Dr. Karen Coats______Dean of the Graduate School

December 2014

ABSTRACT

DIALECT USE WITHIN A SOCIALLY FLUID GROUP OF

SOUTHERN RESIDENT KILLER WHALES, ORCINUS ORCA

by Courtney Elizabeth Smith

December 2014

Resident killer whales, Orcinus orca, of the Northeastern Pacific form stable kinship-based matrifocal associations and communicate with group-specific repertoires of discrete calls (dialects) that reflect these associations. The gradual fission of matrilines is usually consistent with dialect variations among groups that may manifest as differences in call usage at the repertoire level or subtle structural differences of the calls themselves.

Therefore, matrilines that are more closely related tend to be more acoustically similar.

Within the endangered community of Southern Resident killer whales (SRKWs), recent evidence shows that one particular group (L pod) exhibits the lowest rate of intrapod association and has significantly greater associations within matrilines than between matrilines - suggesting they may be undergoing a level of fission that is reflected in their acoustic repertoire. Call production of four L matrilines (L04, L21, L26, and L12) was analyzed over a five-year period (2007-2011). Results showed significant differences in proportional call use and call associations across matrilines, as well as acoustic similarity indices between matrilines that reflect the social fissioning exhibited by L pod. The large size, demography, and seasonal movements of L pod suggest that it may represent a potential conservation target pod and its protection could lead to benefits for the overall recovery of SRKWs. This is the first study to assess matrilineal dialect use of SRKWs and the subsequent knowledge of matrilineal dialect use of specific groups resulting from

this study may prove useful for the future passive acoustic monitoring and management of this endangered population.

DEDICATION

For Doma, for everything.

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ACKNOWLEDGMENTS

This thesis would not have been possible without the support and encouragement of the Southern Resident community of killer whale researchers and naturalists. I would like to thank Kenneth C. Balcomb III, Director of the Center for Whale Research (CWR), for allowing me access to the photo-identification data used in the present investigation and for the opportunity to spend so many hours on the water with the endangered whales that are the focus of this project. I would also like to thank the other staff at the CWR,

Emma Foster, Erin Heydenriech, David Ellifrit, Kelley Balcomb-Bartok, Kim Parsons, and John Durban for helpful discussions and guidance at multiple stages of the project.

The research team and naturalists based at The Whale Museum and Lime Kiln

Point Lighthouse made opportunistic recordings and behavioral data recordings during whale passes; Bob Otis, Jeanne Hyde, Monica Weiland, and Traci Walter deserve particular mention. Jason Wood and Stefan Brager kindly provided me with the

SeaSound acoustic data and associated sighting records, as well as helpful discussion early in the project. Susan Berta and Howard Garret of OrcaNetwork and the Langley

Whale Center provided additional compilations of whale sightings.

The acoustics team, particularly Marla Holt and Candice Emmons, for the

National Oceanic and Atmospheric Administration’s (NOAA) Northwest Fisheries

Science Center graciously shared available data for L pod acoustic recordings. Candice

Emmons was especially helpful with verifying call identifications. Recordings contributed by the NOAA Northwest Fisheries Science Center were collected under the authorization of Scientific Research Permit No.781-1824-00 of the U.S. National Marine

Fisheries Service, Office of Protected Resources.

Lastly, but not least, I wish to thank my thesis committee, Stan Kuczaj, Sheree

Watson, and Alen Hajnal, as well as John K. B. Ford for the many helpful comments and recommendations that shaped the entirety of this project.

TABLE OF CONTENTS

ABSTRACT ...... ii

DEDICATION ...... iv

ACKNOWLEDGMENTS ...... v

LIST OF ILLUSTRATIONS ...... viii

LIST OF TABLES ...... x

CHAPTER

I. INTRODUCTION ...... 1

Background Information and Literature Review Species of Interest Study Subjects: Southern Resident Killer Whale Community Study Objectives

II. METHODOLOGY ...... 13

Field Sightings and Recordings Acoustic Analysis

III. DATA ANALYSIS AND RESULTS ...... 21

Field Sightings and Recordings Acoustic Analysis

IV. DISCUSSION ...... 43

APPENDIXES ...... 54

REFERENCES ...... 74

LIST OF ILLUSTRATIONS

Figure

1. Example of a killer whale matriline. The long dashed line represents probable relations, while short dashed lines represent possible relations. All of the individuals depicted here often travel together as a group, known collectively as the L12s. Image courtesy of the Center for Whale Research (Ellifrit, Heydenreich, & Balcomb III, 2011). Note: L112 is considered deceased as of 2012...... 9

2. Study area. The yellow star (not to scale) denotes the approximate location of the Lime Kiln Lighthouse SeaSound hydrophone array on San Juan Island. Additional recordings were gathered by NOAA Northwest Fisheries Science Center from the surrounding waters of San Juan Island (Haro Strait and the Strait of Juan de Fuca)...... 14

3. Stereotyped call occurrence across all encounters. Top) Total number of discrete calls identified in the current study; Bottom) Call proportions were calculated for each unique call bout and averaged across each call type and subtype. n =745 (single calls not included)...... 24

4. Subpod variation in discrete call use. Tom) Total number of discrete calls identified for the L01 and L12 subpods in current study. Bottom) Call proportions were calculated for each call bout within an acoustic encounter and averaged across each call type and subtype. Note: One S18 call was noted by the L12s (.08% of repertoire use), but value is too small to present in the histogram. n =71325

5. Matrilineal variation in stereotyped call use. Top) Total number of discrete calls identified for the L01 and L12 subpods in current study. Bottom) Call proportions were calculated within each bout then averaged overall. n =713...... 28

6. Percent use of call S31 by the L21 Mat. Values above represent the proportion call S31 was used per acoustic encounter. Proportional use on 8/12/2008 and 9/16/2011 showed a positive, but insignificant, trend in call use compared to that observed on 7/26/2007, coinciding with two possible activities of vocal imprinting……………………...…………………………………………………29

7. Acoustic similarity of L matrilines. Acoustic similarity indices derived from a modified Dice’s coefficient based on the level of call type and subtype sharing between matrilines. Acoustic similarity clustering also reflects the level of social affiliation between these matrilines ...... 31

8. Call type associations across matrilines. Call association indices were derived from a modified Dice’s coefficient based on the frequency of call transitions between each paired comparison. Calls S19 and S22 are closely linked within the

vii

L subpob matrilines, while the L12s show that call S19 is linked to calls S2iii and S8ii...... 41

9. S1 calls produced by L pod. The call on the right was made by L98, the call on the right was recorded by the L21 matriline. Part three, the terminal note, of the call, was missing from all S1 calls made by the L21 matriline ...... 42

viii

LIST OF TABLES

Table

1. Registry of individuals within L pod over the course of the study period (2006- 2011) ...... 11

2. Summary of samples used in the present study ...... 22

3. Summary of call occurrence across matrilines ...... 22

4. Matrilineal call repertoire composition ...... 27

5. Transition matrix and contingency table analysis for combined matrilines ...... 32

6. Transition matrix and contingency table analysis for the L21 matriline ...... 33

7. Transition matrix and contingency table analysis for the L12 matriline ...... 34

8. Transition matrix and contingency table analysis for the L04 matriline ...... 35

9. Transition matrix and contingency table analysis for the L26 matriline ...... 36

10. Transition matrix and contingency table analysis following the removal of same- call transitions for the L21 matriline ...... 37

11. Transition matrix and contingency table analysis following the removal of same- call transitions for the L12 matriline ...... 38

12. Transition matrix and contingency table analysis following the removal of same- call transitions for the L04 matriline ...... 39

13. Transition matrix and contingency table analysis following the removal of same- call transitions for the L26 matriline ...... 40

ix 1

CHAPTER I

INTRODUCTION

Background Information and Literature Review

Social demands contribute to the evolution of communication systems used by highly gregarious mammalian species in such a way that acoustic signals often reflect social organization (de Waal & Tyack, 2003). In cetacean (whale and dolphin) groups, there is a clear correlation between the types of social bonds and the types of acoustic recognition signals used. For species that live in stable family groups, communicative signals tend to be group-specific rather than individually distinctive, as found in the more dynamic fission-fusion societies (Janik, 2009; Tyack, 1986). Group specific signals can show intraspecific variability on either a macrogeographic (regional) or microgeographic

(local) scale (Krebs & Kroodsma, 1980; Mundinger, 1982). Macrogeographic variability, also referred to as geographic variation, generally refers to the acoustic differences between populations that are separated by large distances and that typically do not mix.

As a result, geographic variations in acoustic signals likely evolved due to isolated environmental or genetic differences (Wilczynski & Ryan, 1999). For example, Mitani,

Hunley, and Murdock (1999) attributed the differences in the pant hoot calls between the genetically isolated Gombe and Mahale chimpanzee populations to ecological differences in the habitat acoustics and body size. Bottlenose dolphin populations along the northern edge of the Texas coastline produce higher frequency whistles than those populations further to the south, most likely resulting from different levels of ambient noise (Wang,

Würsig, & William, 1995).

The more subtle structural (i.e., phonetic) differences in acoustic signals on a microgeographic scale shared among animals that live in sympatry, or bound by social rather than geographic confines, are known as vocal dialects (Conner, 1982; Mundinger,

1982). Human dialects also rely on phonetic variations in acoustic signals, but may also include differences in grammar and syntax for discreteness within a shared language

(Labov, 1994). Although the terms ‘geographic variation’ and ‘dialects’ have traditionally been used to describe differences in group-specific acoustic signals,

Lameira, Delgado, and Wich (2010) recently suggested that these terms have been inconsistently applied to signals across species and taxa of terrestrial mammals – thus hindering comparative analyses – and that alternative terms, such as ‘accents’, should be taken into consideration to describe the phonetic differences in acoustic signals. This is also consistent with confounds in defining the discreteness of human dialects.

Dialects have been extensively documented among birds, most notably songbirds

(Oscines: Mundinger, 1982), parrots (Psittaciforms: Wright, Dahlin, & Salinas-Melgoza,

2008), and hummingbirds (Gaunt, Baptista, Sanchez, & Hernandez, 1994). Although more rare in non-human mammals, dialects have also been described in a variety of species, including greater spear-nosed bats (Phyllostomus hastatus: Boughman, 1997); sperm whales (Physeter macrocephalus: Weilgart & Whitehead, 1997); killer whales

(Orcinus orca: Ford & Fisher, 1983); chimpanzees (Pan troglodytes: Crockford,

Herbinger, Vigilant, & Boesch, 2004), pigtail macaques (Macaca nemestruna: Gouzules

& Gouzules, 1990); harbor seals (Phoca vitulina: Van Parijs, Corkeron, & Harvey, 2003); and Weddell seals (Leptonychotes weddellii: Morrice, Burton, & Green, 1994).

True dialects may originate in several manners. Historical emigration of individuals can lead to founder effects, where individuals will disperse from an original population carrying with them a small subset of the original vocal repertoire (Lynch,

1996; Payne, 1981). Unlike geographic variations, dialects may arise as a byproduct of the vocal learning process and social influences, rather than genetically transmitted differences (Andrew, 1962; Janik, 2009; Mundinger, 1982). In some cases, the acoustic environment itself is thought to shape dialects, where calls and call elements are selectively chosen based on their transmission properties (e.g., songbirds: Lynch &

Baker, 1993; Thielcke, 1969). Although physical maturation can influence changes in vocalizations, social influences and adaptations are primarily thought to shape dialects

(Boughman & Moss, 2003; Payne, 1981; Snowden & Hausberger, 1997). Production learning, in which animals learn to produce sounds based on auditory input from social influences (e.g., exposure to conspecific calls), has been documented in many bird and mammal species and is thought to be the primary cause for the evolution of dialects

(Janik & Slater, 2000). The accumulation of vocal learning errors or the preferential copying of certain signals due to social pressures can also lead to the cultural drift of vocal traditions such as dialects (Janik & Slater, 1998, 2000).

The cultural transmission – or, the acquisition, modification and transfer of behaviors through learning and imitation – of vocalizations can occur in one of two ways: by changing the frequency and proportion of call usage within the vocal repertoire or by modifying various elements of the acoustic signal itself (Janik & Slater, 1997, 2000;

Mundinger, 1980). Serrano and Terhune (2002), for example, found that the vocal repertoire of a harp seal population maintained the same set of calls over 31 years, with

4 no additional calls added, but observed various structural changes across several different call types, perhaps as a means to increase call transmission across long distances or high levels of background noise. The contours of common marmoset (Callithrix jacchus)

‘phee’ calls remained stable over a one-year time period, however the call frequencies decreased over that same period, likely an indicator of the individual’s emotional or arousal state (Jones, Harris, & Catchpole, 1993).

Given the strong learning component of vocal traditions, the study of dialect persistence and change provides important information about both the comparative parallels of other behavioral traditions and cultures in certain species and evolutionary divergence and gene flow among populations (Boyd & Richerson, 1985; Lynch, 1996).

While the function of dialects has long been debated, it appears that the selection pressures for group living, specifically inbreeding avoidance, led to the evolution of group-specific dialects (Marler & Tamura, 1962; Nottebohm, 1969). Likewise, dialects that arise as founder effects can also lead to the subsequent emergence of group specific genetic adaptations (Fisher, 1958). Cultural change, like biological evolution, follows a divergent pattern. As such, acoustic divergence can influence genetic divergence by means of assortative (i.e., non-random) mating (Hegelbach, 1986; Lynch, 1996;

Mundinger, 1980; Ripmeester, Mulder, & Slabberkorn, 2010; Slabberkorn & Smith,

2002). For example, songbirds develop regionally distinct, and genetically differentiated, dialect populations derived in part from female mate selection based on local, rather than neighboring, song production (Baker & Cunningham, 1985).

Species of Interest

Killer whales (Orcinus orca) are well known for their group-specific social dynamics and diverse communication systems; their dialects are the best studied among marine mammals. The piscivorous resident killer whales of the northeastern Pacific live in highly stable societies of related individuals within maternal lineages, from which there is rarely permanent member dispersal. The basic unit of these societies is the matriline, which can consist of up to four generations of maternally related individuals due to the generally long life span of killer whales (mean life expectancy for females: 30 years; males: 19 years; Olesiuk, Ellis, & Ford, 2005). Traditionally, resident killer whale societies were organized as: one or more matrilines that almost always associate together

(95% of the time) form a subpod; one or more of these subpods that traditionally associate at least 50% of the time form a pod (Bigg, 1982; Bigg, Olesiuk, Ellis, Ford, &

Balcomb, 1990). However, as populations grow, group members may spend more time apart, eventually leading to matrilineal fission and the formation of new subpods and pods (Bigg et al., 1990; Ford, 1991). Matrilineal fission can be influenced by the death of a matriarch within a matriline, the maturation of offspring within a matriline, or the proportion of adult males within a matriline (Filatova, Burdin, & Hoyt, 2010; Ford &

Ellis, 2002).

A recent reassessment of resident killer whale social organization suggests that pods might not be as stable as originally thought, and that group associations are too dynamic to have social structure definitions based on them. Instead, resident killer whale societies should be based on maternal genealogy (the matriline) because of its stability and independence of changing group dynamics (Ford & Ellis, 2002). All matrilines that

6 associate together and form a breeding population are considered to be part of a community. Two distinct yet sympatric communities of resident killer whales, known as the Northern Residents and Southern Residents, inhabit the waters surrounding

Vancouver Island, British Columbia. The vocal repertoire of killer whales can be broken down into three general categories: clicks, whistles and pulsed calls (Ford, 1989). Clicks are brief (0.8 to 25ms) broadband pulses of sound which are generally emitted in a series, or click train, with a repetition rate of up to 300 clicks/s with energies extending up to about 50 kHz (peak energy levels ranging from 12-25 kHz; Awbrey, Evans, Jehl,

Thomas, & Leatherwood, 1982; Barrett-Lennard, Ford, & Heise, 1996; Schevill &

Watkins, 1966). Whistles are pure tone signals ranging in frequency generally between 6 and 12 kHz (though they can occur as low as 1.5 kHz and as high as 18 kHz), often with no harmonic content, with durations from .005 to 12 seconds (Ford, 1989; Thomsen,

Franck, & Ford, 2001, 2002). Whistles are stereotyped and relatively stable, with some remaining unchanged over a fifteen-year period (Riesch, Ford, & Thomsen, 2006).

Pulsed calls are the most abundant signal of the killer whale vocal repertoires, with distinct tonal properties as a result of high pulse repetition rates (extending to

4000/s) that can be emitted in various patterns and frequencies. Pulsed calls are further defined by acoustic parameters known as the low-frequency component (LFC) or high- frequency component (HFC) (Miller, 2002). Found in all pulsed calls, the LFC consists of multiple shifts in the pulse repetition rate and manifests as a burst-pulse sound. The

HFC appears as an overlapping tonal band, of which the fundamental frequency may range from 2 to 12 kHz with harmonics peaking to more than 100 kHz (Ford, 1989;

Hoelzel & Osborne, 1986). The fundamental differences in these call components suggest

7 unique functions. Calls containing the HFC, or biphonic calls, have higher source levels and a large active space than those without it, suggesting that calls with the HFC are used to communicate over long distances (Filatova et al., 2009; Miller, 2006). Pulsed calls are divided into three categories: discrete, aberrant and variable calls. Discrete call types that are shared between pods may vary with the frequency with which these calls are used, and slight structural variations in the call types that are utilized (Deecke, Ford, & Spong,

2000; Ford, 1989, 1991; Miller & Bain, 2000). Many of these differences are also apparent at the matriline (Deecke et al. 2000; Miller & Bain, 2000) and, to some extent, the individual (Nousek, Slater, Wang, & Miller, 2006).

The behavioral function of discrete calls is somewhat ambiguous, both between and within resident killer whale communities. Discrete calls are most prevalent during traveling and foraging behavioral contexts, while nondiscrete (aberrant and variable) calls and whistles are attributed to social activities (Ford, 1989; Holt, Noren, & Emmons,

2013), though the behavioral function of individual discrete calls appears to vary between the Northern and Southern Residents (Ford, 1984). For example, outside of group-resting, discrete call use of Northern Residents is relatively consistent across all behavioral categories; whereas some of the Southern Resident pods may demonstrate call preferences between traveling and foraging. However, neither of these studies accounted for matrilineal call use; thus it is unclear if the differences in call emphasis are due to behavioral or social factors.

The variation in call repertoires within a breeding population, rather than within the confines of a geographic barrier, indicate that killer whale call repertoires are considered true dialects (Conner, 1982; Ford & Fisher, 1982). Killer whale dialects are

8 believed to function in kinship recognition for related individuals, perhaps as a means to prevent inbreeding, and to maintain group cohesion (Ford, 1991; Miller, Shapiro, Tyack,

& Solow, 2004). Though killer whale dialects remain stable for decades at the repertoire level, there is evidence that some call types, but not all, may be modified over time, suggesting that killer whale dialects are culturally transmitted through vocal learning rather than genetically inherited (Crance, Bowles, & Garver, 2014; Deecke et al., 2000;

Yurk, Barrett-Lennard, Ford, & Matkin, 2002). The similarity in group specific dialects and call structures reflects the level of genetic relatedness and social affiliation in killer whale societies, but the link between relatedness and associations is much weaker than that between genetic relatedness and acoustic similarity (Deecke, Barrett-Lennard,

Spong, & Ford, 2010). Thus, dialects themselves may be driving matrilineal associations, as social affiliates may be chosen based on kin recognition through call similarity. As a result, the gradual fission of matrilines into new pods typically corresponds with dialect and call structure divergence (Ford, 1991). Thus, pods that diverged more recently may produce more similar versions of some call types. These factors all lend to the usefulness of the killer whale dialect system as a tool for identifying and tracking killer whale populations and their subsequent social groups.

Study Subjects: Southern Resident Killer Whale Community

Southern Resident killer whales (SRKWs) mainly inhabit the waters of southern

Vancouver Island and Puget Sound, Washington, with Haro Strait and the Strait of Juan de Fuca being the core habitat during most of the year (Figure 1). Long-term studies, conducted in large part by the Center for Whale Research (CWR), have monitored the

Southern Resident killer whale population since the 1970s. Extensive demographic and

9 life history information has been obtained by annually resighting individuals using their unique physical attributes (saddle patch patterns and colorations, dorsal fin shape, distinctive scars or wounds; see Figure 1) that allow for easy recognition and photo identification (Balcomb, Boran, & Heimlich, 1982; Bigg, 1982). The Southern Resident killer whale (SRKW) population has experienced a 20% decline since 1996 (Krahn et al.,

2002) which prompted its listing as ‘endangered’ by the Committee on the Status of

Figure 1. Example of a killer whale matriline. The long dashed line represents probable relations, while short dashed lines represent possible relations. The individuals depicted here often travel with the L32 matriline and are collectively referred to as the L12s. Image courtesy of the Center for Whale Research (Ellifrit, Heydenreich, & Balcomb III, 2011). Note: L12 is considered deceased as of 2012.

Endangered Wildlife (COSEWIC) under the Species at Risk Act (SARA) in Canada

(Baird, 2001), and as an ‘endangered’ distinct population segment under the U.S.

Endangered Species Act. As of June, 2014, approximately eighty individuals are currently assigned to three pods: J, K and L (Center for Whale Research, unpublished). J pod currently has 26 individuals; K pod is the smallest with around 18 individuals, with L pod, the largest of the three SRKW pods, consisting of 36 individuals and 11 matrilines.

Over time, it has been suggested that L pod may be diverging into several new pods (see Baird, Hanson, & Dill, 2005; Foster, 2006; Hoelzel, 1993), following the delineations of the currently recognized L subpods (L01, L02, and L12; Foster, 2006).

These groupings largely mirror the L8, L10 and L35 subpods described in the initial social assessment of Southern Residents (Bigg et al., 1990; Table 1). More recent studies using long-term association data (across three decades) further supports this. Specifically,

J and K pods had higher annual intra-pod associations than L pod and that L pod was the only pod with significantly greater associations within matrilines than between matrilines, with the average rate of association highest among whales within each of the three recognized L subpods (Parsons, Balcomb III, Ford, & Durban, 2009). This suggests that smaller maternally related groups become more important in situations where pods grow to a point that it becomes too costly, in terms of resource procurement, to associate with all other pod members (Parsons et al., 2009). For example, the social groupings of

Southern Residents fragment to single matrilines or subpods in years with lower prey density (Foster et al., 2012), which was particularly apparent in the larger L pod (Foster,

2006). An investigation of matrilineal dialect use may further reflect the social fissioning of L pod.

Table 1

Registry of individuals within L pod over the course of the study period (2007-2011)

Subpod Subpod Subpod Subpod Mat ID Mom Sex Cat Birth Death Mat ID Mom Sex Cat Birth Death Past Pres Past Pres L08 L01 L04 L27 L04 F A 1965* L08 L02 L02 L02 F A 1960* 2012

L08 L01 L04 L55 L04 F A 1977 L08 L02 L02 L67 L02 F A 1985 2008

L08 L01 L04 L82 L55 F A 1990 L08 L02 L02 L78 L02 M A 1989 2012

L08 L01 L04 L86 L04 F A 1991 L08 L02 L02 L88 L02 M A 1993

L08 L01 L04 L103 L55 F J 2003 L08 L02 L02 L101 L67 M J 2002 2008

L08 L01 L04 L106 L86 M J 2005 L08 L02 L09 L05 L09 F A 1931* 2012

L08 L01 L04 L109 L55 M B 2007 L08 L02 L09 L73 L05 M A 1986 2009

L08 L01 L04 L112 L86 F B 2009 2012 L08 L02 L09 L74 L03 M A 1986 2009

L08 L01 L04 L116 L82 M B 2010 L08 L02 L09 L84 L51 M A 1990

L08 L01 L04 L118 L55 U B 2011 L35 L02 L35 L54 L35 F A 1977

L08 L01 L08 L57 L45 M A 1977 2008 L35 L02 L35 L100 L54 M J 2001

L08 L01 L21 L21 F A 1950* 2008 L35 L02 L35 L108 L54 M J 2006

L08 L01 L21 L47 L21 F A 1974 L35 L02 L35 L117 L54 U B 2010

L08 L01 L21 L83 L47 F A 1990 L10 L12 L12 L12 F A 1933* 2012

L08 L01 L21 L91 L47 F J 1995 L10 L12 L11 L41 L11 M A 1977

L08 L01 L21 L110 L83 M B 2007 L10 L12 L11 L77 L11 F A 1987

L08 L01 L21 L111 L47 F B 2008 2008 L10 L12 L11 L94 L11 F J 1995

L08 L01 L21 L115 L47 M B 2010 L10 L12 L11 L113 L94 F B 2009

L08 L01 L26 L26 F A 1956* 2013 L10 L12 L11 L114 L77 U B 2010

L08 L01 L26 L90 L26 F J 1993 L08 L12 L25 L25 F A 1928*

L08 L01 L26 L92 L60 M J 1995 L10 L12 L32 L22 L32 F A 1971*

L08 L01 L37 L72 L43 F A 1986 2010 L10 L12 L32 L79 L22 M A 1979 2013

L08 L01 L37 L95 L43 M J 1996 L10 L12 L32 L85 L28 M A 1991

L08 L01 L37 L105 L72 M J 2004 L10 L12 L32 L87 L32 M A 1992

L08 L01 L37 L07 L37 F A 1961* 2012 L10 L12 L32 L89 L22 M J 1993

L08 L01 L37 L53 L07 F A 1977

Note. Subpod past designations based on social groups delineated by Bigg et al. (1990). Present designations based on a social network analysis spanning from 1996-2003 (Foster, 2006). Asterisks denote estimated birth-years based on long term population monitoring.

Study Objectives

Understanding the evolution of dialects increases our understanding of the effects of social behavior on genetic divergence and speciation. Since killer whale dialects are representative of genetic relatedness, social affiliations and group membership (Deecke et al., 2010), it is likely that L pod’s matrilineal dialect use may be exhibiting the same plasticity as that of their inter-annual associations. This possibility is addressed in the current study by assessing the acoustic genealogy of L pod through the following objectives: (1) Characterize call repertoire composition and current calling behavior of individual L matrilines; (2) Determine acoustic similarity through call use between L matrilines; (3) Quantify the features of calls produced by individual L matrilines, particularly the shared calls among L matrilines. Such information is warranted; despite more than four decades of dedicated study, the matrilineal dialect use of Southern

Resident killer whale has not yet been assessed. Following the methods of similar historical research efforts, the present study provides the first assessment of intra-pod variation in call use amongst Southern Resident killer whales.

CHAPTER II

METHODOLOGY

Field Sightings and Recordings

Opportunistic field recordings of L matrilines were collected from within the

Salish Sea (study area approximate range: N48º22’–49º, W122º43’–123º18’; Figure 1) over five years (2007-2011) from two main sources. The primary source was a fixed hydrophone array, part of the SeaSound Hydrophone network, based just offshore of

Lime Kiln Point Lighthouse on San Juan Island (N48°30’, W123°09’) in approximately 8 meters of water. This site is ideal for monitoring killer whales, as they pass the lighthouse almost daily during the summer and early fall months. Southern Residents often travel in mixed-pod groupings during this time; to ensure a robust data pool, only recordings with single L pod encounters were considered for analysis. Multiple whale sightings databases from regional partners, naturalists and independent researchers were screened to identify when single L matrilines were present during each pass, though all recordings were ultimately ground-truthed with photo-identification and sighting records maintained by the Center for Whale Research.

Where possible, all analyses were restricted to the fundamental matrilineal groups. In some cases, however, matrilines were pooled together following the social organization determined by Foster (2006) for subpod level analyses. The L12 matrilineal group (consisting of the L11 and L32 matrilines, along with the individuals L85 and L12;

Table 1; Figure 1) has traveled independently for many years and is recognized as a separate social group in certain scientific and naturalist circles. As a result, sighting records often reference the presence of this group as being separate from other L pod

Figure 2. Study area. The yellow star (not to scale) denotes the approximate location of the Lime Kiln Lighthouse SeaSound hydrophone array on San Juan Island. Additional recordings were gathered by NOAA Northwest Fisheries Science Center from the surrounding waters of San Juan Island (Haro Strait and the Strait of Juan de Fuca).

15 encounters, but do not detail the presence or absence of the specific matrilines within this group (e.g., the L11 matriline may travel alone or with the L32s and be documented as the L12s in both occasions, but may or may not include L12 herself). Indeed, there is often a level of ambiguity as to the membership of the L12 group, as they occasionally fragment. It is likely that these two main groups are fragmented from the death of a matriarch. Given the social ambiguity of the L12 matrilineal groups, the L12 Mat and

L12 Sub were collectively considered synonymous in the present study.

Various hydrophones at the Lime Kiln site were used over the course of the study period largely due to weather damage to each deployed system. In 2007, an altered Navy

Sonobuoy hydrophone (uncalibrated; with streamed recordings at a sampling rate of 44.1 kHz) was deployed until the system failed during extreme low tides of Spring 2008. A temporary hydrophone was deployed from July 2008 until late August when a Reson

TC4032 hydrophone was installed for the remainder of the study period. Each system had an adequate flat frequency response covering a range from at least 1-100 kHz, appropriate for detecting orca calls.

Three additional recordings of L matrilines from 2008 and 2009 were contributed by the NOAA Northwest Fisheries Science Center that were obtained during a separate, vessel-based research endeavor within the study area (see Holt, Noren, & Emmons, 2011,

2013). These data were collected using a calibrated omnidirectional Reson TC-4033 hydrophone (connected to a low-noise preamplifier and then to an A/D device which digitized the signals at a sampling rate of 192 kHz) deployed from an 8 m research vessel that was positioned approximately 1 km ahead of (i.e., in front of the path) a group of whales with the vessel engine shut off. Whale identifications were made from

16 experienced personnel (and former CWR staff) on-board at the time of recording.

The conglomerate nature of the recordings did not allow for behavioral data to be collected in a consistent manner across encounters. Rather, general notes on behavioral state for each encounter were included in the sighting database; behavioral events

(Altmann, 1974) were rarely noted. However, the general behavior of the whales in each of the recordings involved individuals being spread out, with group members swimming consistently in the same direction, often including long duration dives – collectively is consistent with the probable searching during foraging (Holt et al.,, 2012).

Acoustic Analysis

Recordings were spectrographically screened using Raven Pro 1.4 sound analysis software (Cornell Laboratory of Ornithology, Ithaca, New York, USA). As the recording systems and sampling rates varied throughout the study, spectrograms were generated using Fast-Fourier Transformations (FFT) with Hamming window sizes ranging from

1024 - 4096 points for each analyzed time series with an 87.5% overlap, yielding a time resolution ranging from 2.67 - 2.90 ms and a frequency resolution of 43.0 – 46.9 Hz.

Acoustic signals were audio-visually screened and coded into four broad categories (as described in the introduction): buzzes, pulsed calls, whistles, and other (being sounds that did not clearly fall into the other categories). Calls were further segregated as being variable or stereotyped, with stereotyped calls encompassing both discrete calls and the occasional aberrant version of respective call types (as first devised by Ford, 1984, 1987).

Only stereotyped calls were included in further analyses. The stereotypic nature of killer whale discrete call types (and the occasional aberrant versions) enables both naïve and

17 trained observers to correctly categorize calls based on their overall gestalt, often with high levels of accuracy (e.g., Deecke, Ford, & Spong, 1999; Yurk et al., 2002).

Call Repertoire Composition

Call rates of many taxa are known to naturally vary during acoustic encounters, largely due to brief call exchanges known as bouts. To account for this, stereotyped call bouts in the current study were defined by a bout criterion interval of 19.5 s (simplified from the 19.6 criterion as determined by Miller et al., 2004). Anecdotally, the calling bouts observed in the current study naturally followed this temporal resolution. The proportion of stereotyped calls was then calculated within each calling bout, to be used to test the null hypothesis that there were no differences in the frequency of occurrence of each call type. These data followed a zero-inflated Poisson distribution that could not be normalized with known power transformation techniques (e.g., the traditional arcsine square root transformation commonly in killer whale dialect studies); therefore, the data were tested non-parametrically. Proportion data for each call type per bout were used as replicates in a k-sample Kruskall-Wallis test to determine significant differences among means, with a Dunn’s test and Bonferroni Correction to determine significance across all possible comparisons.

Finally, the acoustic similarity of L matrilines was determined using a weighted index derived from Dice’s coefficient of association (Ford, 1991; Ivkovich, Filatova,

Burdin, Sato, & Hoyt, 2010; Strager, 1995):

where Nc is the total number of call types shared, Ns is the total number of subtypes

shared, and R1and R2 are the respective repertoire sizes (call types plus subtypes) of the two matrilines being compared. The calculated similarity indices were then hierarchically arranged using an average-linkage cluster analysis (Ford, 1991; Morgan,

Simpson, Hanby, & Hallcraggs, 1976).

Patterns of Call Occurrence

Resident killer whales are known to produce calls in various sequences, with certain calls associated (i.e., heard within a similar context) with each other more often than others (e.g., Ford, 1987, 1991; Saultis, Matkin, & Fay, 2005; Strager, 1995).

Determining calling behavior between individuals is difficult; in the absence of directional hydrophones and recording equipment and without knowing the precise behavioral contexts and locations of individuals, it is nearly impossible to get a clear sense of calling sequences between individuals (e.g., Miller et al., 2004). Therefore, most analyses on patterns of call occurrence are restricted to first order transitions (Ford, 1984,

1987; Slater, 1973). In the present study, patterns in calling behavior were determined by calculating preceding-following call transition frequencies within each of the defined calling bouts, which were then tallied into a transition frequency matrix and compared to expected probabilities of occurrence by testing for independence using Fisher’s Exact

Test (Quinn & Keough, 2002). To further account for the a priori knowledge that killer whale calls are known to follow disproportional occurrence rates (i.e., calling behavior follows rules of quasi-independence; see Goodman, 1968), with self-transitions prevalent in calling behavior (Ford, 1991; Miller et al., 2004), further testing was needed to identify significant call transitions. To do this, self-transitions (i.e., the diagonal frequencies) were removed from the matrix to eliminate the influence dominant calls on the other call types

19 and conditional probabilities were calculated for the remaining (off-diagonal) call sequences (Lemon & Chatfield, 1971).

A mover-stayer log-linear model (Lindsey, 1995) was then used to test for independence among remaining call transitions (i.e., quasi-independence), with outlier tests of residuals to determine significance of each pairwise comparison (significance set at p<.01; see Ford, 1989; Lemon & Chatfield, 1971). To further present the relationship between call sequences, the transition frequencies for each possible call combination were summed and used in calculating another modified Dice’s coefficient of association that normalizes the differences in call abundance:

where i is the preceding call and j is the following call within a calling bout (Ford, 1984).

Call Structure Analysis

Calls that were distinct (e.g., having a low signal to noise ratio) were measured across various time-frequency parameters using classification criteria set in previous studies assessing killer whale call variations: 1) the points of measurement should roughly describe the LFC and HFC call components; 2) re-measure call parameters previously measured by Ford (1984, 1987); and 3) take multiple measurements of the pulse-repetition rate (i.e., sideband interval; see Watkins, 1967) of the LFC and the fundamental frequency band of the HFC at the same temporal point (Miller & Bain,

2000). Measurements of call parameters were made using the Selection Table tool within

Raven 1.4; the data for each file were stored and exported as a text file that was later imported into Microsoft Excel for analysis. Descriptive statistics were calculated for

20 each of the separate call components; where possible, call parameter comparisons were made between matrilines to determine structural differences (Appendix A).

CHAPTER III

DATA ANALYSIS AND RESULTS

Field Sightings and Recordings

Following the criteria set to determine acoustic recordings for analysis, 12 independent recordings of L pod were considered suitable for further testing, yielding

361 minutes of acoustic footage, over 10 distinct days from 2007-20111 (Appendix A).

Nine recordings were of single matrilines (Mat): L04 Mat (n=1), L12 Mat (n=4), L21

Mat (n=3) and the L26 Mat (n=1). The remaining three recordings were of mixed matrilines and subpods of the following combinations: L01 and L12 Mats (n=1); L01 and

L02 Mats (n=1); and L02 and L12 Mats (n=1). Due to the limited representation the mixed recordings could provide, they were not directly used to characterize intra-pod variation in call use, but were instead used to infer possible call use by the presence/absence of each call type. Indeed, the same level of caution was given to the interpretation of results for the L04 and L26 matrilines.

Acoustic Analysis

Echolocation clicks, whistles and pulsed calls were identified in each of the acoustic encounters. Of 931 identified pulsed calls, 150 were coded as being variable

(n=72; 7.73%) or too faint to be accurately ascribed to any stereotyped category (n=78;

8.34%); the resulting 781 stereotyped calls (discrete: n=741; aberrant: n=40; 83.89%) comprised 122 call bouts (Table 2). Single calls (n=36) that were not attributed to a vocal exchange (call bout) were eliminated from call pattern analysis, leaving 86 individual call bouts containing 745 calls to assess repertoire composition and patterns of

1 A recording from 9 July 2007 met the study criteria, however the whales were silent during the encounter and the recording was therefore eliminated from the analysis.

Table 2

Summary of samples used in the present study

Matrilines L09 L02 L12 L04 L12 L21 L26 L12 L21 Total L26 L35 L26 Number of call bouts 18 27 60 8 2 5 2 122 (3) (13) (14) (3) (0) (2) (1) (36) Number of encounters 1 4 3 1 1 1 1 12 Total call bout duration 573.1 511.8 1556.2 186.1 41.5 74.8 5.5 2949 Average bout duration 15.0 30.2 18.3 25.9 37.2 20.8 2.8 Total calls w/in bouts 126 194 390 31 11 25 4 781

Note. Numbers in parentheses represent the number of single call bouts. Call bout durations reported in seconds.

Table 3

Summary of call occurrence across matrilines

Call n (%) Mean SD Min Max S1* 10 (11.6) 5.1 18.2 0.0 100.0 S2iii 8 (9.3) 5.3 17.8 0.0 85.4 S6* 5 (5.8) 1.9 11.3 0.0 100.0 S8ii 8 (9.3) 4.1 18.5 0.0 100.0 S10 13 (15.1) 5.5 17.5 0.0 100.0 S13i* 1 (1.1) 0.4 4.0 0.0 37.5 S13ii - - - - - S16 12 (14.0) 8.9 25.3 0.0 100.0 S18 11 (12.8) 3.2 12.9 0.0 100.0 S19 28 (32.6) 18.2 32.0 0.0 100.0 S22 19 (22.1) 7.3 17.8 0.0 100.0 S31 42 (48.8) 37.8 44.1 0.0 100.0 S33 5 (5.8) 1.1 5.9 0.0 50.0 S36 1 (1.2) 0.2 1.8 0.0 16.7 S37ii - - - - - S40 4 (4.7) 1.1 6.5 0.0 50.0 S42 - - - - -

Note. Values in the above table are based on multi-call bouts during acoustic encounters made by single matrilines present study

(n=86); single call bouts were eliminated to reduce inflation of call proportional use.

23 occurrence. Most single calls were also heard in call bouts, with the exception of call

S17 (n=1), and S36 (n=2; with only one call heard within a call bout) (Table 3).

Call Repertoire Composition

Call repertoire size for the pooled matrilines (n=15) in the present study was the same as that originally described for the entirety of L pod from 1978-1983 (n = 15; Ford,

1987, 1991). However, there are noticeable differences between the two time periods, particularly with regards to repertoire composition. Calls S13ii, S37ii and S42 were documented in the original dialect assessment, but were not heard in any of the recordings from the present study. This is noteworthy, as the recording sample size for acoustic encounters in the present study is roughly half of that of the original study, yet the number of unique call types identified remained nearly the same. Alternatively, three additional call types historically associated with J pod – calls S1, S6 and S13i – were observed in acoustic recordings of the present study. However, whereas the S6 and S13i calls have not previously been documented outside of J pod, call S1 was produced frequently by a lone, sociable member of L pod (L98) over a period of five years when separated from his natal group, the L02 matriline (Foote, Griffin, Howitt, Larsson, Miller,

& Hoelzel, 2006). Prior to this event, call S1 had never been documented outside of J pod. Six calls were shared between the four matrilines: calls S10, S16, S18, S19, S22 and

S31. The shift in the composition of L pod’s (collective) call repertoire observed in present study as compared to the past also revealed marked differences in the proportion of call use across the study (Figure 3), at both the subpod and matrilineal levels (Figures

4 & 5, respectively).

Figure 3. Stereotyped call occurrence across all encounters. Top) Total number of discrete calls identified in the current study; Bottom) Call proportions were calculated for each unique call bout and averaged across each call type and subtype. n =745 (single calls not included).

Figure 4. Subpod variation in discrete call use. Top) Total number of discrete calls identified for the L01 (blue) and L12 (red) subpods in current study. Bottom) Call proportions were calculated for each call bout within an acoustic encounter and averaged across each call type and subtype. Note: One S18 call was noted by the L12s (.08% of repertoire use), but value is too small to present in the histogram. n =713.

While call repertoire sizes were equal between the L12 matrilineal group and that of the L01 subpod, there were apparent differences in proportional call use between the two social groups. Specifically, the L12s were the sole producers of the S2iii and S8ii call subtypes, both of which collectively comprised nearly half of their call production in the current study (25.7 and 24.1%, respectively; see Figure 4). However, the S2iii call was heard far more frequently than the S8ii and was found in more call bouts comprising other calls, whereas the S8ii was heard less frequently but in bouts with lower call diversity, thus suggesting call S2iii may be the dominant call of the L12 subgroup.

Indeed, these calls were heard in all recordings where the L12 matrilines were present

(even in cases where they were fragmented or in the presence of mixed subpods), and were never observed in their absence. The S31 and S16 call types were the second most frequently used calls by the L12s (19.1 and 14.3%, respectively), while calls S10, S18,

S19, S36 and S40 each occurred less than 5% of the total proportion of calls produced by the L12s. While the L12s appeared to have exclusive use of two calls, the L01 subpod broadly showed the same trend; calls S1, S6, S18 and S33 were only heard in recordings made of the L04, L26 and L21 matrilines. Call S22 production was nearly equal between the two subpods, comprising 7.7 and 7.9% of the L12 and L01 subpods, respectively.

Call use between matrilines deviated from collective observations of the subpods as a whole, with clear differences in call repertoire composition between matrilines

(Table 4). These differences were significant across and within L matrilines (H = 174.57, df=13, p < 0.0001). Specifically, calls S19, S22, and S31 were used significantly more often than other call types (p < 0.0001; Bonferroni corrected α = 0.0005) and in some cases were revealed to be the dominant call type of specific matrilines (Figure 5). Call

Table 4

Matrilineal call repertoire composition

______L01 Sub______L12 Sub Call Type L04 L21 L26 L12 L Pod Past S1 X S2iii X X S6 X X X S8ii X X S10 X X X X X S13ii X S16 X X X X S17 X X S18 X X X X X S19 X X X X X S22 X X X X X S31 X X X X X S33 X X S36 X X S37ii X S40 X X X S42 X

Note. Summary of call types used by selected Southern Resident killer whale matrilines and subpods in the present study, as compared to past repertoire assessments (see Ford, 1987, 1991). Highlighted marks denote calls unique to matrilines (blue = L21 Mat, pink = L26 Mat, yellow = L12 Mat). n=713. repertoire sizes were nearly equal between the matrilines comprising the L04, L21, and

L26 matrilines (n =7, 9 and 8, respectively). This is noteworthy, as only a single recording was available for the L04 and L26 matrilines, compared to three available for the L21 Mat. Calls S19 and S31 were the most frequently produced calls by the L01 subpod, however the most striking difference is that call S19 appeared to dominate L04

Mat call production at 61% and only comprised 10% or less of each of the other matrilines. A similar trend was found for call S31, which made up 56% and 60% of

L21Mat and L26 Mat repertoire, but only 19% of the L12 Mat repertoire. Call S18 was

28 produced more often by the L04 matriline than the other L matrilines (at 13.5%). Call

S22 was produced more often by the L04 and L26 matrilines (~17% and 14%), than by the L12 and L21 matrilines.

Figure 5. Matrilineal variation in stereotyped call use. Top) Total number of discrete calls identified for the L01 and L12 subpods in current study. Bottom) Call proportions were calculated within each bout then averaged overall. n =713.

The overall frequency of call S31 was unexpected given its low production described in past assessments of L pod call use; most recently, calls S2iii and S19 have been noted as the most prolific calls produced by L pod (Foote, Osborne, & Hoelzel,

2008). Upon closer inspection of its use by the L21 Mat, call S31 was emitted at least three times more often during two separate encounters (8/12/2008 and 9/16/2011) than was observed on the other date, though this trend was not statistically significant

(Kruskal-Wallis test: H=1.973, df=2, p=0.373, two-tailed; Figure 6). Interestingly, the acoustic encounter of 8/12/2008 coincided with the very recent (within a few hours) birth

Figure 6. Percent use of call S31 by the L21 Mat. Values above represent the proportion call S31 was used per acoustic encounter. Proportional use on 8/12/2008 and 9/16/2011 showed a positive, but insignificant, trend in call use compared to that observed on 7/26/2007, coinciding with two possible activities of vocal imprinting.

of a new calf (L111, born to L47); the L21 matriline was observed isolated, in a tight group just off the Lime Kiln hydrophone array (Center for Whale Research, unpublished data). During this acoustic encounter, call S31 represented 64% of the calls recorded.

This shift in call use is consistent with observations of Northern Residents, which

30 significantly increase the production matrilineal calls in the presence of newborn calves

(Weiß, Ladich, Spong, & Symonds, 2006).

The second encounter (9/16/2011) involved a brief period where L91 was separated from her natal group, who had traveled further north of the Lime Kiln lighthouse while L91 stayed behind, very close to the SeaSound array. During this time, an extended call bout (426 seconds) ensued where L91 emitted a string of the core calls utilized between all L matrilines (S18, S19, S22), including call S33; during this bout, call S19 – many in aberrant form - dominating call production. As the remaining L21 Mat turned south, toward L91, faint S19 calls could be heard. Anecdotally, after the faint

‘response’ calls, the aberrant versions of call S19 were no longer observed. Shortly after the reunion, call S31 production increased to 56% of calls emitted during that encounter, possibly as a means to assert group identity after the reunion. Given the behavioral contexts during these two encounters featuring bouts of increased production of call S31, it seems likely that it may be the primary contact call of the L21 matriline. If so, this may explain why broad social calls (i.e., those shared between all L matrilines) were more prevalent during the period of separation rather than when all members of a matriline were together.

Overall, the differences in usage of shared and exclusive call types (Table 5) revealed various levels of acoustic similarity between the matrilines: the L21 and L26

Mats were most similar (0.700), both of which had a close association with the L04 Mat

(.634); the L12 matrilineal group was most acoustically distinct from the others (0.340)

(Figure 7). Not unexpectedly, these clusters also reflect the intra-pod associations as described in recent years (e.g., Foster, 2006).

Patterns of Call Occurrence

As observed with call repertoires, the sequencing of calls also varied between matrilines. A contingency table analysis using Fisher’s Exact test revealed highly significant call transition patterns for the four matrilines (p<.05). Similar to past assessments of resident killer whale calling behavior (e.g., Ford, 1989; Miller et al.,

2004), L pod exhibited a strong tendency for self-transition (Table 5).

Additionally, there was a strong pattern of occurrence for the S2iii and S8ii call types to occur together than with other calls, as well as call S22 to follow calls S18 and S6. To some degree, the self-transitions were also significant (p<.01) within single-matriline call sequencing (Tables 6-9). However, when reduced to matriline-specific transitions, the association between calls S2iii and S8ii was no longer considered significant. The

Figure 7. Acoustic similarity of L matrilines. Acoustic similarity indices derived from a modified Dice’s coefficient based on the level of call type and subtype sharing between matrilines. Acoustic similarity clustering also reflects the level of social affiliation between these matrilines.

Table 5

Transition matrix and contingency table analysis for combined matrilines

Following Call S1 S2iii S6 S8ii S10 S16 S18 S19 S22 S31 S33 S36 S40 S1 6 0 0 0 0 0 0 0 0 3 0 0 0 S2iii 0 94 0 11 1 0 1 12 0 0 0 1 1 S6 0 0 5 0 0 0 2 0 6 0 0 0 0 S8ii 0 10 0 4 0 0 0 1 0 0 0 0 0 S10 0 0 0 0 4 2 0 2 2 7 0 0 0 S16 2 0 0 0 0 13 0 0 1 5 0 0 0 S18 0 1 1 0 0 0 16 7 12 0 0 0 1 S19 0 13 3 0 1 0 8 144 9 2 4 0 0 S22 0 0 4 0 3 1 7 12 26 0 3 0 0 S31 5 2 0 0 6 2 0 2 1 116 1 0 0 S33 0 0 0 0 0 0 3 3 1 1 7 0 0 S36 0 0 0 0 0 0 0 0 0 0 0 0 1

Call S40 0 1 0 0 0 0 0 1 0 0 0 0 1 A.

S1 S2iii S6 S8ii S10 S16 S18 S19 S22 S31 S33 S36 S40

Preceding S1 + ------ns - - - S2iii - + - + ns ------ns ns S6 - - + - - - ns - + - - - - S8ii - + - + - - - ns - - - - - S10 - - - - + ns - ns ns ns - - - S16 ns - - - - + - - ns ns - - - S18 - - ns - - - + ns + - - - ns S19 - - ns - ns - ns + ns - ns - - S22 - - ns - ns ns ns ns + - ns - - S31 ns - - - ns ns - - - + ns - - S33 ------ns ns ns ns + - - S36 ------ns S40 - ns - - - - - ns - - - - ns B.

Note. A) Transition matrix showing frequency of calls made by the L04, L21, L26 and L12 matrilines combined (n=628). B)

Contingency table analysis using Fisher’s Exact test (p < .001 significance) for significant matrilineal call transitions against a random model (+ = observed > expected; – = observed < expected; ns = not significant).

significant association between calls S6, S18 and S22 persisted with the L21 matriline and was not found to be significant in the other matrilines.

Table 6

Transition matrix and contingency table analysis for the L21 matriline

Following Call

S1 S6 S10 S16 S18 S19 S22 S31 S33

S1 6 0 0 0 0 0 0 3 0 S6 0 1 0 0 2 0 3 0 0 S10 0 0 2 2 0 0 2 7 0 S16 2 0 0 11 0 0 1 5 0 S18 0 1 0 0 13 2 10 0 0 S19 0 1 1 0 3 86 2 1 4 S22 0 3 2 1 4 5 3 0 3

S31 5 0 6 2 0 1 1 107 1 S33 0 0 0 0 3 3 1 1 7 A.

S1 S6 S10 S16 S18 S19 S22 S31 S33

Preceding Call Preceding S1 + ------ns - S6 - ns - - ns - + - - S10 - - ns ns - ns ns ns - S16 ns - - + - - ns ns - S18 - ns - - + - + ns - S19 - ns - - - + - - ns S22 - + ns ns ns ns ns ns ns S31 ns - ns - - - - + - S33 - - - - ns ns ns - + B.

Note. A) Transition matrix showing frequency of calls made by the L21 (n=330) matriline. B) Contingency table analysis using

Fisher’s Exact test (p < .05) for significant matrilineal call transition against a random model (+ = observed > expected; – = observed

< expected; ns = not significant).

Self-transitions were removed to further test the significance of off-diagonal call transitions (Tables 10-13). Call S22 showed a significant tendency to follow S18 calls

(p<.01) for the L21 Mat (Table 10), while the L12 Mat displayed significance for call transitions involving calls S22 and S19, and calls S36 and S40 (Table 11). The L26

Table 7

Transition matrix and contingency table analysis for the L12 matriline

Following Call

S2iii S8ii S16 S18 S19 S22 S31 S36 S40

S2iii 94 11 0 1 12 0 0 1 1 S8ii 10 4 0 0 1 0 0 0 0 S16 0 0 2 0 0 0 0 0 0 S18 1 0 0 0 0 0 0 0 0 S19 13 0 0 0 5 0 0 0 0 S22 0 0 0 0 1 1 0 0 0 S31 2 0 0 0 0 0 3 0 0 S36 0 0 0 0 0 0 0 0 1 S40 1 0 0 0 0 0 0 0 1 A.

S2iii S8ii S16 S18 S19 S22 S31 S36 S40

Preceding Call Preceding S2iii + ns - ns ns - - ns - S8ii ns ns - - ns - - - - S16 - - + ------S18 ns ------S19 ns - - - ns - - - - S22 - - - - ns + - - - S31 ------+ - - S36 ------+ S40 ns ------ns B.

Note. A) Transition matrix showing frequency of calls made by the L12 (n=167) matriline. B) Contingency table analyses using

Fisher’s Exact test (p < .05) for significant matrilineal call transition against a random model (+ = observed > expected; – = observed

< expected; ns = not significant).

matriline showed significant transitions with calls S18 and S19. However, these transitions are based on only a single call transition for each pair; hence, a larger sample is needed before making firm conclusions about these transitions. The L04 Mat showed no significant call transitions after the self-transitions were removed from the analysis.

Table 8

Transition matrix and contingency table analysis for the L04 matriline

Following Call

S6 S10 S18 S19 S22 S31 S40

S6 2 0 0 0 2 0 0

S10 0 1 0 2 0 0 0

S18 0 0 3 4 2 0 1

S19 2 0 5 53 6 1 0

S22 0 1 2 6 13 0 0

S31 0 0 0 1 0 0 0

S40 0 0 0 1 0 0 0

S6 S10 S18 S19 S22 S31 S40 Preceding Call S6 + - - - ns - -

S10 - ns - ns - - -

S18 - - ns ns ns - ns

S19 ns - ns + - ns -

S22 - ns ns - + - -

S31 - - - ns - - -

S40 - - - ns - - -

Note. A) Transition matrices showing frequency of calls made by the L04 (n=108) matriline. B) Contingency table analyses using

Fisher’s Exact test (p < .05) for significant matrilineal call transition against a random model (+ = observed > expected; – = observed

< expected; ns = not significant).

The cluster analyses showed that several calls are strongly associated across matrilines (Figure 8). There is a clear link of association between calls S19 and S22 within the L04, L21 and L26 matrilines which comprise the L01 subpod. Call S19 is also used by the L12 matrilineal group, though its use appears secondary to that of the dominantly used S2iii call type. In all matrilines, call S10 – and to some extent call S16

Table 9

Transition matrix and contingency table analysis for the L26 matriline

Following Call S6 S10 S18 S19 S22 S31

S6 2 0 0 0 1 0 S10 0 1 0 0 0 0 S18 0 0 0 1 0 0 S19 0 0 0 0 1 0 S22 1 0 1 0 9 0

S31 0 0 0 0 0 6

S6 S10 S18 S19 S22 S31

Preceding Call S6 ns - - - ns - S10 - ns - - - - S18 - - - ns - - S19 - - - - ns - S22 ns - ns - + - S31 - - - - - + B.

Note. A) Transition matrices showing frequency of calls made by the L26 (n=23) matriline. B) Contingency table analyses using

Fisher’s Exact test (p < .05) for significant matrilineal call transition against a random model (+ = observed > expected; – = observed

< expected; ns = not significant).

(see L12 and L21 matrilines) – was not clearly linked with other calls within a matriline’s repertoire.

Similar to Ford’s (1984) past assessment of call associations, calls S36 and S40 were closely linked, however these calls were rarely observed and were only though this pairing was only observed in the L21 Mat. In general, calls S2iii and S19 have remained distinct within call clusters due to the frequency of their occurrence; however, it is clear that this trend reflects matrilineal differences.

Table 10

Transition matrix and contingency table analysis following the removal of same-call transitions for the L21 matriline

Following Call S1 S6 S10 S16 S18 S19 S22 S31 S33

S1 0 0 0 0 0 0 3 0

S6 0 0 0 2 0 3 0 0

S10 0 0 2 0 0 2 7 0

S16 2 0 0 0 0 1 5 0

S18 0 1 0 0 2 10 0 0

S19 0 1 1 0 3 2 1 4

S22 0 3 2 1 4 5 0 3

S31 5 0 6 2 0 1 1 1

S33 0 0 0 0 3 3 1 1

S1 S6 S10 S16 S18 S19 S22 S31 S33

Preceding Call S1 ------ns - S6 - - - ns - ns - - S10 - - ns - ns ns ns - S16 ns - - - - ns ns - S18 - ns - - - + ns - S19 - ns - - - - - ns S22 - ns ns ns ns ns ns ns S31 ns - ns - - - - - S33 - - - - ns ns ns -

Note. A) Transition matrices for the off-diagonal call sequences observed for the L21 (n=94) matrilines. B) – = Significant call transitions as revealed by an outlier test of model residuals for each call transition (p < .01) (+ = observed > expected; observed < expected; ns = not significant).

Call Structure Analysis

Discrete calls that were encountered during the study were measured across various time-frequency parameters and compared with descriptive statistics to the

Table 11

Transition matrix and contingency table analysis following the removal of same-call transitions for the L12 matriline

Following Call S2iii S8ii S16 S18 S19 S22 S31 S36 S40

S2iii 11 0 1 12 0 0 1 1

S8ii 10 0 0 1 0 0 0 0

S16 0 0 0 0 0 0 0 0

S18 1 0 0 0 0 0 0 0

S19 13 0 0 0 0 0 0 0

S22 0 0 0 0 1 0 0 0

S31 2 0 0 0 0 0 0 0

S36 0 0 0 0 0 0 0 1

S40 1 0 0 0 0 0 0 0

S2iii S8ii S16 S18 S19 S22 S31 S36 S40

Preceding Call S2iii ns - ns ns - - ns ns S8ii ns - - ns - - - - S16 ------S18 ns ------S19 ns ------S22 - - - - + - - - S31 ns ------S36 ------+ S40 ns ------B.

Note. A) Transition matrices for the off-diagonal call sequences observed for the L12 (n=56) matriline. B) – = Significant call transitions as revealed by an outlier test of model residuals for each call transition (p < .01) (+ = observed > expected; observed < expected; ns = not significant).

differences in call structures between matrilines; however these values can serve as a foundation for future comparisons. In general, call structure variables remained relatively

Table 12

Transition matrix and contingency table analysis following the removal of same-call transitions for the L04 matriline

w C

ol lo al

in S6 S10 S18 S19 S22 S31 S40 S6 0 0 0 2 0 0

S10 0 0 2 0 0 0

S18 0 0 4 2 0 1

S19 2 0 5 6 1 0

S22 0 1 2 6 0 0

S31 0 0 0 1 0 0

S40 0 0 0 1 0 0

S6 S10 S18 S19 S22 S31 S6 - - - ns - - Preceding Call S10 - - ns - - -

S18 - - ns ns - ns S19 ns - ns ns ns - S22 - ns ns ns - - S31 - - - ns - - S40 - - - ns - - B.

Note. A) Transition matrices for the off-diagonal call sequences observed for the L04 (n=36) matriline. B) Significant call transitions as revealed by an outlier test of model residuals for each call transition (p < .01) (+ = observed > expected; – = observed < expected; ns = not significant).

stable over time – the exception being call durations, which have increased in a majority of L pod (and, overall, Southern Resident) calls types (Weiland, Jones, & Renn, 2010).

Two calls in particular merit further description: calls S1 and S8ii. The version of call S1 produced by the L21 matriline in the present study differs from that used by J pod in that it is missing part three, or the terminal note (Figure 9). Furthermore, the end of part two – now the end frequency value – is higher than the end of part two as previously

Table 13

Transition matrix and contingency table analysis following the removal of same-call transitions for the L26 matriline

Following Call S6 S10 S18 S19 S22 S31 S6 0 0 0 1 0 S10 0 0 0 0 0 S18 0 0 1 0 0 S19 0 0 0 1 0 S22 1 0 1 0 0 S31 0 0 0 0 0 A.

S6 S10 S18 S19 S22 S31 S6 - - - ns -

Preceding Call S10 - - - - - S18 - - + - - S19 - - - ns - S22 ns - ns - - S31 - - - - -

Note. A) Transition matrices for the off-diagonal call sequences observed for the L26 (n=5) matriline. B) Significant call transitions as revealed by an outlier test of model residuals for each call transition (p < .01) (+ = observed > expected; – = observed < expected; ns

= not significant).

described by Ford (1984, 1987). It could therefore be suggested that call S1 may be designated into subtypes, with the L pod version of S1 now referred to as call S1i. Given recording equipment limitations in past studies, call components were often not measured beyond 8 kHz. The present study analyzed call features up to 12 kHz. As a result, a previously undescribed HFC of call S8ii was noted and measured, with a range extending from 10.5 to 12 kHz; thus call S8ii should now be considered a biphonic call.

Call Association Index

Call Type or Subtype

Figure 8. Call type associations across matrilines. Call association indices were derived from a modified Dice’s coefficient based on the frequency of call transitions between each paired comparison. Calls S19 and S22 are closely linked within the L01 subpod matrilines, while the L12s show that call S19 is linked to calls S2iii and S8ii.

Figure 9. S1 calls produced by L pod. The call on the right was made by L98, the call on the right was recorded by the L21 matriline. Part three, the terminal note, of the call, was missing from all S1 calls made by the L21 matriline.

CHAPTER IV

DISCUSSION

Southern Resident killer whales have matrilineal distinct dialects as evidenced by proportional differences in call usage, variation in call sequencing, and matrilineal- specific calls at the repertoire level. Furthermore, this acoustic differentiation between matrilines is mirrored in the higher order social groupings of killer whale societies, between the L01 and L12 subpods. These findings are consistent with past studies of killer whale dialects, further demonstrating that genetic factors – and in turn, social affiliation – is reflected in the acoustic behavior of resident killer whales; matrilines that are more closely related have a higher degree of call sharing and social affiliation than less genetically similar conspecifics (Barret-Lennard, 2000; Deecke et al. 2010).

The call repertoire composition of the sampled matrilines offers further insight into the social divergence within L pod, as none of the sampled matrilines produced all of the calls originally described for the entirety of L pod; each matriline had a discrete set of calls with several being unique to individual matrilines. The L12s produced two calls specific to their social group, calls S2iii and S8ii, whereas all other calls observed in the study were shared by at least one other matriline. In resident killer whales, social isolation will eventually lead to dialect divergence (Ford, 1991). The L12s have long been referred to as a socially distinct group from the remainder of L pod. Though there is no quantitative association data that demonstrate this, the use of two unique call types suggests that this matrilineal group may be more genetically distinct from the other L matrilines. The preferred use of biphonic calls (S2iii, S8ii, and S19) by the L12s may further support this, as biphonic calls contain both short and long-range call components

44 to convey group identity information in the near and far-fields. The L32 matriline has a stronger association with the L12 matriline than the other L matrilines (Foster, 2006) though they do not always travel with them (personal observation). In this case, it may be beneficial for the greater L12 subgroup to utilize biphonic calls to maintain group cohesion over greater spatial – and social – distances. Indeed, the larger and more socially fluid nature of L pod overall is thought to be the reason they produce more biphonic calls than either of the other Southern Resident pods (Foote et al., 2008).

On the other hand, call S31 – a monophonic call – appears to be the dominant call of the L21 matriline. This is supported by the two encounters involving the apparent vocal imprinting that occurred during the repetitive use of call S31 shortly (within hours) after the birth of L111 (e.g., Weiß et al., 2006), and also during the vocal exchange involving L91 and the remainder of her natal group. However, caution should be used in this latter scenario because they may have also shifted their behavioral state, which may have involved a bout of social activity as a result of the union (which was not noted in sighting records). Across killer whale societies in the eastern north Pacific, monophonic calls have a greater diversity in call structure than biphonic calls, likely due to the fact that there are more matrilines than pods and group identifiers should be unique (Filatova et al., 2012). Thus, it seems likely that the more socially isolated a matriline is, the more likely the dominant call representing group identity will be monophonic. Overall, call use within the both the L12 and L21 matrilines suggests that monophonic and biphonic calls denote the various levels of acoustic and social hierarchy. For example, call S31 and call

S2iii may be specific family badges for the L21 and L12 matrilines, respectively.

Whereas, the common use of call S19 – a biphonic call – suggests that this call is equally

45 important in identifying as members of L pod as a whole. This could also explain why calls S8ii and S2iii were closely associated in the transition matrix; call S2iii may be the group identifier for the broader L12 subgroup that includes the both the L12 and L32 matrilines; whereas call S8ii may only be associated with only a single matriline (in this case, L12).

The lack of observation of other calls associated with L pod is also telling; several calls were missing (e.g., S13ii, S37ii, and S42) or under-represented (e.g., S36, heard in only a single call bout made by the L12s) in the recordings of the sampled matrilines.

One possibility is that these calls are associated with matrilines belonging to the L02 subpod of whales, which were not assessed in the present study. Indeed, Reira (2012) reported the presence of call S36 in the majority of the L pod acoustic encounters from hydrophones deployed on Swiftsure Bank, off the entrance of Juan de Fuca Strait – an area that L pod frequents (Hauser, Logsdon, Holmes, VanBlaricom, & Osbourne, 2007), including the L02 subpod which is the less frequently encountered L group within the core study area (personal observation).

Alternatively, the lower than expected proportion of use (as compared to prior assessments) of other calls observed in the present study could simply mean that some calls are more prominent in multi-matriline aggregations. For example, the production of the primary call types of each Southern Resident pod was found to decrease by more than

5% during multi-pod encounters (Foote et al., 2008). This is also consistent with the finding that Northern Resident matrilines increase the production of matriline-specific call subtypes when in the presence of other groups (Weiß et al., 2006). Overall, call S19 – previously defined as the dominant call of L pod – comprised only 18% of calling

46 behavior in the present study, a decrease from a past assessments of ~ 35% (Ford, 1984;

Foote et al., 2008). While the percent use of call S16 by L pod has increased from Ford’s original assessment (see Foote, 2005), call S17 was rarely heard in the present study. This is telling, as L pod was noted in the past to produce these calls in sequence - with S17 calls often following S16 calls (Ford, 1984). These two calls are currently known as the dominant calls of K pod, comprising more than half of their call production (Foote et al.,

2008). Perhaps some individuals from L pod are dropping it from their call repertoire as a means to further differentiate group identities. Indeed, the A05 pod within the Northern

Resident community is the only group amongst eight A-clan pods that does not produce some version of call N1 (Ford, 1989).

Finally, the decrease in the use of certain calls might also be a product of cultural drift as a result of the loss of individuals. Some individuals within a matriline may use some calls more often than others (e.g., Miller et al., 2004) and vocal divergence may be influenced by group-specific behavioral trends, perhaps initiated by a socially dominant member within each pod or lineage, such as a matriarch (Ford, 1984). Additionally, the removal of specific individuals from a killer whale society might have profound effects on their social network (Williams & Lusseau, 2006). The Southern Residents experienced a sharp, 20% population decline in the mid-1990’s, which could have resulted in the general shift in L pod call use. This would also be consistent with a past finding that acoustic similarity between pods did not coincide with inter-pod associations, likely a result of their social relationships – and thus dialects – stabilizing after a significant culling period (1967-1973) during which an estimated 27% of the total Southern Resident population was captured and removed for public display (Bigg, 1982; Ford, 1984).

The addition of call S1 to the L pod call repertoire is interesting, particularly because it has been identified as J pod’s dominant call for nearly four decades (Ford,

1989; Foote et al., 2008). This call has now been documented in at least two L matrilines belonging to different social groups (L01 and L02 subpods). The absence of the terminal note was apparent in all S1 calls observed by the L21 Mat, but not in the versions made by L98, suggesting that the adoption of a modified S1 call may be the emergence of a new call subtype. The modification of the terminal endings to calls appears to be the first step in vocal divergence of killer whale groups, and has been noted between multiple

Northern Resident matrilines (Deecke et al. 2000; Ford, 1984; Miller & Bain, 2000).

Notwithstanding the noted differences in matrilineal repertoire composition and discrete call use, the similarities between the L matrilines also speak to the social dynamics within L pod. Five of the calls (1/3 of all calls) observed in the study were noted across all sampled matrilines, with these same calls comprising roughly half of each matriline’s discrete call repertoire. This suggests the importance of an individual’s pod membership, in addition to that of matrilines. For example, the near exclusive use of shared L calls by L91 during her period of separation from the L21 matriline likely maximized her opportunity of contacting her larger social group (L pod) versus that of only her matriline.

Despite the lack of consistency in behavioral context – which may influence patterns of call use (Ford, 1989; Hoelzel & Osborne 1986; Holt et al., 2013) – across recordings of sampled matrilines, several patterns of call associations were noted across and within matrilines (Figure 8). Consistent with prior assessments that call S19 is a dominant call of L pod, it was prominently associated with core calls within each of the

48 sampled matrilines. The most defining trend was the strong association between calls S19 and S22, which were associated in each sampled matriline of the L01 subpod.

Alternatively, call S22 had a low association with these same call when made by the L12 group. This not only demonstrates that some calls may serve specific functions, but that these functions may also differ between matrilines. For example, dominant male weddell seals (Leptonychotes weddellii) use fewer stereotyped calls within a calling bout prior to surfacing at a breathing hole as a means to assert territoriality, as opposed to submissive seals that increase the diversity of calls within the same context (Terhune & Dell’Apa,

2006). Similarly, some units that comprised dominant call patterns within humpback whale songs have acoustic features that are more intense than lesser-used units, suggesting differences in functionality (Mercado III, Herman, & Pack, 2003).

Not all discrete calls are thought to convey group identity. In fact, some of the lesser-used calls in the study are also not exclusive to L pod, or even the Southern

Resident community. For example, the structure and pitch of call S10 is similar to call types across multiple killer whale populations across the northeast Pacific, and has since been referred to as a universal excitement call (Rehn, Filatova, Durban, & Foote, 2011).

This could explain why call S10 was not closely associated with the core group of calls across the sampled matrilines in the present study (Figure 8). It is possible that call S6 may serve a similar function; since Ford’s (1984) original repertoire assessment, it appears to have been added to L pod’s repertoire and is now known to occur across all pods of the Southern Residents.

Acoustic differences within killer whale societies have long been believed to serve as acoustic badges to promote the discreteness of group identities, which can

49 facilitate inbreeding avoidance. Unlike the Northern Resident killer whale community, which is comprised of three acoustic clans between which breeding occurs, Southern

Residents are genetically isolated and comprise only a single acoustic clan that may be the product of a genetic bottleneck, with very low genetic diversity (Hoelzel, Dahlheim,

& Stearn, 1998; Pilot, Dahlheim, & Hoelzel, 2010). As a result, breeding within this community occurs both between and within pods. Indeed, genetic studies show that even in cases where within-pod breeding occurs whales within this community avoid mating with closely related individuals (e.g., siblings and parents) (Ford et al., 2011). It is likely that matrilineal dialect differences may be the key behavioral process driving this mating behavior. For example, L41 – a member of the L12 matriline – was found to have been one of the more successful breeding males within the Southern Resident population, fathering calves belonging to the more acoustically distinctive J and K pods.

Alternatively, J1 – another prominent breeder of this community - fathered more calves within J and K pods, both more acoustically similar than L pod (Ford et al., 2011). Given the findings of the present study that the L12s are so acoustically distinct lends further support that vocal discreteness of matrilineal dialects may aid in inbreeding avoidance.

The applications of this study extend beyond defining social groups and their behavior. In recent years, passive acoustic monitoring (PAM) techniques – noting presence of species through remote acoustic monitoring – have sharply increased in use for monitoring this population (Hanson, Emmons, Ward, Nystuen, & Lammers, 2013;

Reira, 2012) and mitigating potential adverse effects from anthropogenic impacts. The

Southern Residents face multiple human-use threats within their core summer habitat of the Salish Sea. For example, marine renewable energy development is increasing in this

50 region, with two open-duct tidal turbines to be deployed in Admiralty Inlet by 2015

(Carlson, Jepsen, & Copping, 2013). Not only can PAM be used for scoping marine mammal occurrence during the siting for these developments, marine energy devices can also be outfitted with auto-detection software that can trigger shut-down mechanisms to prevent strike when Southern Residents, and other marine mammals, are in the area

(Polagye et al., 2014). Knowing the specific calling behavior of matrilines could aid in determining possible adverse interactions as a result of human-use activities in the event of a stranding or death. For example, the death of L112 (of the L04 matriline) in 2012 has been suggested to be the result of blunt force acoustic trauma as a result of Navy sonar operations that were occurring in the area. L pod calls were detected on hydrophones within the spatial and temporal vicinity of this event (Balcomb, 2014), but without a clear understanding of the L04 matrilines calling behavior it is impossible to know if she was, in fact, present at the time of Navy operations. The L04 matriline was sampled in the current study, however with only one recording available additional sampling of this group alone is needed before determining their matrilineal call use. The same is true for the L26 matriline. Indeed, the results of this study with respect to call repertoires are far more clear for the L21s and L12s than the other sampled matrilines. Additional data is warranted across all matrilines to better understand patterns of call use and call stability.

However, it should be noted that although the recording sample size (and number of calls) is relatively small in this study, it is comparable to data sets used in similar past assessments of killer whale calling behavior and therefore likely that a matrilines’ full repertoire was sampled despite the few hours of recordings (e.g., Foote et al., 2008; Ford,

1984; Miller et al. 2004; Miller & Bain, 2002; Wieland et al., 2010). Indeed, during the

L91 separation event, 5 of the 8 calls comprising the L21 call repertoire were produced by a single individual; the remaining calls are rarely observed in this matriline (e.g., call

S1) or considered excitement calls that may function in multi-group encounters (e.g., calls S6 and S10; see Rehn et al., 2011).

The present study had several noteworthy limitations. In general, each of the analyses and subsequent conclusions would be more robust with additional recordings of single matrilines within L pod. Although it is likely that all of the calls comprising a matrilines’ repertoire were captured for the L12 and L21 matrilines in the present study, the same cannot be said for the L04 and L26 matrilines. Likewise, those matrilines belonging to the L02 subpod of whales were missing from the present study. Given the exclusive use of the S2iii and S8ii calls by the L12 matrilines, it may be possible to screed past recordings to determine the presence of the L12s within the study area, thus improving sighting records for this particular social group. Indeed, such a retroactive assessment was used in the past to identify the natal groups of whales removed from the wild for public display purposed (e.g., Ford, 1984). Overall, the lack of detail in sighting records to determine the presence (and hence, recordings) of specific matrilines was the greatest limitation for the present study; this in turn limited the number of usable recordings for analysis. Unlike studies of Northern Resident killer whales, which have notated sightings of killer whales by matrilineal groups for decades, researchers and citizen science groups focusing on Southern Residents killer whales rarely adopt this practice and continue to note the presence of pods – contrary to the recommendations made by leading killer whale experts (Ford & Ellis, 2002). This is particularly detrimental for assessing L pod occurrence, as they rarely are sighted as an entire pod

(personal observation). Unfortunately, many sighting records of this group only contain ambiguous statements referencing group presence, such as ‘some of L pod’. While photo- identification efforts can better tease out which individuals are present, this is often only maintained by a handful of research groups who are, in some cases, experiencing increasingly reduced field efforts due to funding cuts. It is imperative that an overhaul of the sighting network occurs to improve records of specific matrilines in the area.

Likewise, due to lack of detailed behavioral data concurrent with recordings of isolated matrilines the possibility that proportional call use may be more of a function of behavior

(e.g., Ford, 1984, 1989) rather than social organization cannot be ruled out. However, the isolated presence and proportional use of the S2iii and S8ii calls by the L12 matrilineal group suggests the latter scenario is more likely. Dedicated field efforts combining behavioral focal follows of whales outfitted with acoustic tags (e.g., DTAGs; Holt et al.,

2013) are needed to ground-truth the calling behavior of isolated Southern Resident matrilines. This will help researchers to better understand group-specific shifts in habitat use over time (e.g., Hauser et al., 2007; Reira, 2012) and can establish a better baseline for future directed studies across multiple disciplines.

In this respect, knowing matrilineal calling behavior can also help to facilitate this process. For example, the impacts of noise on the behavior and physiology (i.e., stress response) of Southern Resident killer whales is a mounting concern. Within Haro Strait, commercial shipping is the most significant source of consistent noise – heard approximately 80% of the time – with received sound levels that can reduce the communication range of orcas by roughly 50% (Veirs & Veirs, 2006). Southern

Residents have already shown that they increase call amplitude and in response to

53 background noise levels increases (Holt, Noren, Veirs, Emmons, & Veirs, 2009; see also right whales: Parks, Johnson, Nowacek, & Tyack, 2011). Knowledge of how matrilines utilize certain call types may reveal whether some matrilines are more impacted by noise than others. For example, given that monophonic calls are produced at lower source levels than biphonic calls (Holt et al., 2011; Miller et al., 2004), groups that utilize monophonic calls more often than biphonic calls may be more susceptible to acoustic masking. With regards to the present study, the L21 matriline may fit this paradigm and should be the focus of future studies.

The study of killer whale dialects over time not only gives insight into the social organization and discreteness of association patterns and groupings among individuals; pod and matrilineal dialect use are also essential to understanding the behavioral, social and ecological attributes of killer whale societies. Overall, the large size and demography of L pod suggests it may represent a potential conservation target pod and that its protection could lead to benefits for the overall recovery of the Southern Resident killer whale population. For this reason, dialect use should be further explored within a broader ecological context to better understand what is driving L pod social organization and possible fragmentation. For the endangered community of Southern Resident killer whales, the need to explore these factors may be imperative to their survival.

APPENDIX A

Summary of Recordings Used in the Analysis

Recording Duration Recording Date Matriline Subpod Observed Call Types Onset (min) Source 7/3/07 16:26 14 L12, L21, L26 L01, L12 S31 SeaSound 7/5/2007 A 9:04 30 L04 L01 S6, S18, S19, S10, S22 SeaSound 7/5/2007 B 10:45 20 L12, L32 L12 S2iii, S8ii, S10, S19, S22, S36, S40 SeaSound 7/26/07 15:15 21 L21 L01 S1, S10, S19, S22, S31, S33 SeaSound 6/14/08 15:17 42 L26 L01 S6, S10, S16, S17, S18, S19, S22, S31 SeaSound 7/25/08 14:43 7 L12, L32 L12 S2iii, S8ii, S19, S31, S40 SeaSound 8/12/08 13:15 26 L21 L01 S1, S10, S16, S19, S22, S31, S33 SeaSound 8/21/2009 A 14:52 10 L02, L21, L26 L01, L02 S1, S13i, S16, S19, S22 NWFSC 8/21/2009 B 15:19 12 L12, L32 L12 S2iii, S8ii NWFSC 9/1/09 13:58 71 L11, L12, L32 L12 S2iii, S8ii, S16, S18, S19, S31 NWFSC 5/14/10 16:53 49 L09, L11, L12, L32, L35 L02, L12 S2iii, S8ii, S19 NWFSC 9/16/11 8:05 59 L21 L01 S1, S6, S17, S18. S19, S22, S31, S33 SeaSound

APPENDIX B

Catalogue of Discrete Calls Produced by L matrilines and Description of Discrete Call

Time-Frequency Parameters Measured

Included in this appendix are several of the L pod calls sampled from the current study. Calls were measured up to 12 kHz, an increase from the original measurements first described for these calls (Ford, 1984, 1987). As a result, some call parameters may be new and are not compared to prior measurements. Due to high levels of noise in the sampled recordings, calls suitable for measurement were too few in number to statistically compare between matrilines. Descriptive statistics, as previously described in the methods, are included here. The following abbreviations are listed in the measurement tables:

General Statistics

C.V. = coefficient of variation (standard deviation/mean x 100) n = sample size (calls clear enough for measurement) Min = minimum value of measurement Max = maximum value of measurement

Frequency measurements SBI = sideband interval Hz = frequency in Hertz f = frequency

Duration measurements Dur = duration ms = milliseconds s = second IPI = interpulse interval

Whale social groupings Mat = matriline Sub = subpod (as defined earlier in the manuscript) L Pod Pres = all values from current study pooled as L pod L Pod Past = original values reported in Ford (1984, 1987)

Call S1

Part 1 Part 2 ______

Measurement Social Group Mean C.V. Min Max n Dur (ms) L21 Mat 1148 5.2 1086 1269 9 L Pod Pres 1140 11.7 833 1373 11 J Pod Past 884 38.5 527 1986 52 Part 1 Dur (ms) L21 Mat 943 6.6 856 1070 9 L Pod Pres 921 15.0 562 1083 11 J Pod Past 629 44.5 341 1464 48

SBI, start (Hz) L21 Mat 1131 11.6 979 1339 9 L Pod Pres 1105 13.0 854 1339 11 J Pod Past 1020 6.1 885 1178 52

SBI, end (Hz) L21 Mat 1161 11.8 946 1355 9 L Pod Pres 1144 11.4 946 1355 11 J Pod Past 1065 11.6 880 1515 52 Part 2 Dur (ms) L21 Mat 174 13.0 145 221 9 L Pod Pres 188 20.0 145 257 11 J Pod Past 151 52.2 95 308 48

SBI, start (Hz) L21 Mat 1089 10.5 901 1272 9 L Pod Pres 1073 10.3 901 1272 11 J Pod Past 693 19.4 546 1370 48

Call S1 (continued).

Measurement Social Group Mean C.V. Min Max n SBI, end (Hz) L21 Mat 942 23.8 438 1194 9 L Pod Pres 865 31.0 407 1194 11 J Pod Past 573 13.4 403 733 48

Call S2iii

Part 1 Part 2 ______

Measurement Social Group Mean C.V. Min Max n Dur (ms) L12 Sub 860 20.1 583 1338 31 L Pod Past 617 23.8 384 982 26 Part 1 Dur (ms) L12 Sub 496 24.9 325 786 31 L Pod Past 466 29.5 216 873 26

Time to L12 Sub 229 34.2 126 471 31 upsweep (ms) L Pod Past 304 32.0 194 613 26

SBI, start (Hz) L12 Sub 589 24.0 338 946 31 L Pod Past 554 9.9 464 688 26

SBI, end (Hz) L12 Sub 2517 12.0 1405 2916 31 L Pod Past 2649 6.0 2651 2887 26 Part 2 Dur (ms) L12 Sub 272 23.5 180 480 31 L Pod Past 150 30.7 79 268 26

SBI, start (Hz) L12 Sub 570 25.2 399 893 32 L Pod Past 150 30.7 79 268 26 SBI, start (Hz) L12 Sub 570 25.2 399 893 32 L Pod Past 606 18.8 408 828 26

Call S2iii (continued).

Measurement Social Group Mean C.V. Min Max n SBI, end (Hz) L12 Sub 517 24.8 355 863 31 L Pod Past 542 20.4 336 793 26 HFC (Tone) Dur (ms) L12 Sub 563 22.4 327 853 31 L Pod Past - - - - - f, start (Hz) L12 Sub 4823 15.3 3000 6857 31 L Pod Past 5557 4.5 5103 6033 25 f, end (Hz) L12 Sub 6671 7.6 6028 8075 31 L Pod Past 6419 12.2 6207 7375 24

Call S6

Measurement Social Group Mean C.V. Min Max n Dur (ms) L21 Mat 313 21.9 264 361 2 L04 Mat 393 28.6 250 567 8 L01 Sub 377 25.4 250 567 10 J Pod Past 466 17.4 315 580 21

SBI, start (Hz) L21 Mat 1031 3.6 1004 1057 2 L04 Mat 1151 30.3 531 1502 8 L01 Sub 1127 27.6 531 1502 10 J Pod Past 950 15.1 686 1176 21

SBI, peak (Hz) L21 Mat 1004 7.4 952 1057 2 L04 Mat 1104 18.2 513 1637 8 L01 Sub 1024 10.3 513 1637 10 J Pod Past 1033 12.5 861 1336 21

SBI, end (Hz) L21 Mat 555 57.3 235 555 2 L04 Mat 1040 13.2 275 348 8 L01 Sub 403 17.3 235 555 10 J Pod Past 251 16.4 170 343 21

Call S8ii

Part 1 Part 2 ______

Measurement Social Group Mean C.V. Min Max n Dur (ms) L12 Sub 512 17.9 331 614 10 L Pod Past 501 13.1 399 642 14 Part 1 Dur (ms) L12 Sub 234 60.6 69 433 10 L Pod Past 409 16.5 280 523 14

IPI, start (ms) L12 Sub 18 39.8 7 27 10 L Pod Past 29 18.7 21 42 14 Part 2 Dur (ms) L12 Sub 117 23.9 79 158 10 L Pod Past 92 14.5 73 119 14

SBI, start (Hz) L12 Sub 1480 80.2 758 3781 10 L Pod Past 734 9.4 667 924 14

SBI, end (Hz) L12 Sub 5232 29.2 3014 7498 10 L Pod Past 5495 18.3 4300 7300 14 HFC (Tone) Dur (ms) L12 Sub 234 13.9 190 244 10 f, start (Hz) L12 Sub 1049 6.5 1023 1120 10 f, peak (Hz) L12 Sub 1170 4.2 1098 1188 10 f, end (Hz) L12 Sub 1008 11.4 980 1105 10

Call S16

Measurement Social Group Mean C.V. Min Max n Dur (ms) L21 Mat 481 30.8 310 568 3 L1+L2 Sub 1066 21.3 838 1444 5 L Pod Pres 847 42.2 310 1444 8 L Pod Past 1088 30.6 709 1333 3

Time to L21 Mat 387 37.2 221 475 3 downsweep L1+L2 Sub 675 14.6 565 818 5 (ms) L Pod Pres 567 32.3 221 818 8 L Pod Past 857 29.7 564 1023 3

SBI, start (Hz) L21 Mat 1096 14.8 912 1218 3 L1+L2 Sub 1025 13.4 826 1139 5 L Pod Pres 1052 13.3 826 1218 8 L Pod Past 1258 7.9 1147 1336 3

SBI, start of L21 Mat 865 22.3 645 1005 3 downsweep L1+L2 Sub 876 12.6 713 1008 5 (ms) L Pod Pres 872 15.2 645 645 8 L Pod Past 1228 6.6 1160 1317 3

Call S18

Chirps Part 1 ______

Measurement Social Group Mean C.V. Min Max n Chirps No./Call L04 Mat 682 9.9 605 730 3 L21 Mat 486 4.2 451 486 5 L01 Sub 560 19.4 451 730 8 L Pod Past 428 24.1 294 565 11

Dur (ms) L04 Mat 219 21.4 166 255 3 L21 Mat 191 9.5 163 209 5 L01 Sub 201 15.9 163 255 8 L Pod Past 128 35.6 79 211 14 f, start (Hz) L04 Mat 157 36.2 94 204 3 L21 Mat 115 16.5 101 147 5 L01 Sub 131 30.5 94 204 8 L Pod Past 127 14.7 108 174 14 Part 1 Dur (ms) L04 Mat 109 15.6 98 129 3 L21 Mat 111 25.8 79 145 5 L01 Sub 111 21.3 79 145 8 L Pod Past 79 56.6 42 177 14

SBI, start (Hz) L04 Mat 367 26.3 267 538 6 L21 Mat 327 12.1 241 377 13 L1 Sub 339 18.6 241 538 19 L Pod Past 377 8.6 327 427 16

Call S18 (continued).

Measurement Social Group Mean C.V. Min Max n Part 1 Dur (ms) L04 Mat 109 15.6 98 129 3 L21 Mat 111 25.8 79 145 5 L01 Sub 111 21.3 79 145 8 L Pod Past 79 56.6 42 177 14

SBI, start (Hz) L04 Mat 367 26.3 267 538 6 L21 Mat 327 12.1 241 377 13 L1 Sub 339 18.6 241 538 19 L Pod Past 377 8.6 327 427 16

SBI, end (Hz) L04 Mat 735 11.7 615 852 6 L21 Mat 645 9.6 510 739 13 L1 Sub 672 11.9 510 852 19 L Pod Past 757 6.9 685 846 11

Call S19

Measurement Social Group Mean C.V. Min Max n Dur (ms) L21 Mat 598 20.2 408 829 48 L4 Mat 538 48.6 308 765 4 L1 Sub 593 22.4 308 829 52 L12 Sub 652 33.9 360 941 8 L Pod Pres 619 34.9 360 941 7 L Pod Past 730 22.1 330 1099 35 LFC (Pulsed part) L21 Mat 551 22.0 333 823 48 Dur (ms) L04 Mat 408 44.1 260 631 4 L01 Sub 540 24.1 260 823 52 L12 Sub 482 38.1 244 752 8 L Pod Pres 533 25.9 244 823 60 L Pod Past 485 28.1 169 833 35

SBI, start (Hz) L21 Mat 1036 15.1 608 1383 48 L04 Mat 909 44.4 476 1347 4 L01 Sub 1026 17.8 476 1383 52 L12 Sub 871 33.1 588 1139 8 L Pod Pres 1005 18.9 476 1383 60 L Pod Past 827 23.5 471 1365 35

SBI, mid (Hz) L21 Mat 1257 14.6 930 1809 48 L04 Mat 1647 55.5 788 2538 4 L01 Sub 1287 23.5 788 2538 52 L12 Sub 1235 7.6 1100 1373 8 L Pod Pres 1280 22.1 788 2538 60 L Pod Past - - - - -

Call S19 (continued).

Measurement Social Group Mean C.V. Min Max n SBI, end (Hz) L21 Mat 1610 20.3 849 2295 48 L04 Mat 1331 26.5 1026 1709 4 L01 Sub 1589 21.0 849 2295 52 L12 Sub 1587 22.1 941 2063 8 L Pod Pres 1589 21.0 849 2295 60 L Pod Past 2004 23.5 13.03 31.28 35 HFC (Tone) Dur (ms) L21 Mat 555 24.0 348 797 48 L04 Mat 379 44.4 222 535 4 L01 Sub 541 26.3 222 797 52 L12 Sub 624 33.2 358 873 8 L Pod Pres 552 27.7 222 873 60 L Pod Past 682 24.8 240 1063 35 f, start (Hz) L21 Mat 5021 2.1 4815 5318 48 L04 Mat 4822 1.1 4766 4869 4 L01 Sub 5005 2.3 4766 5318 52 L12 Sub 4923 4.5 4522 5216 8 L Pod Pres 4994 2.7 4522 5318 60 L Pod Past 4874 2.9 4562 5127 35 f, end (Hz) L21 Mat 5676 6.6 5166 6922 48 L04 Mat 7332 29.3 5241 9687 4 L01 Sub 5804 13.3 5166 9687 52 L12 Sub 5604 3.8 5158 5843 8 L Pod Pres 5777 12.6 5158 9687 60 L Pod Past 5885 11.1 4976 7751 35

Call S22

Part 1 Part 2 ______

Measurement Social Group Mean C.V. Min Max n Dur (ms) L04 Mat 682 9.9 605 730 3 L21 Mat 486 4.2 451 486 5 L01 Sub 560 19.4 451 730 8 L Pod Past 428 24.1 294 565 11 Part 1 Dur (ms) L04 Mat 219 21.4 166 255 3 L21 Mat 191 9.5 163 209 5 L01 Sub 201 15.9 163 255 8 L Pod Past 128 35.6 79 211 14

SBI (Hz) L04 Mat 157 36.2 94 204 3 L21 Mat 115 16.5 101 147 5 L01 Sub 131 30.5 94 204 8 L Pod Past 127 14.7 108 174 14 Part 2 Dur (ms) L04 Mat 466 6.1 450 499 3 L21 Mat 268 35.4 181 394 5 L01 Sub 342 36.9 181 499 8 L Pod Past 299 23.8 196 417 11

Dur, level part L04 Mat 109 15.6 98 129 3 (ms) L21 Mat 111 25.8 79 145 5 L01 Sub 111 21.3 79 145 8 L Pod Past 79 56.6 42 177 14

Call S22 (continued).

Measurement Social Group Mean C.V. Min Max n SBI, start (Hz) L04 Mat 889 14.6 848 972 3 L21 Mat 993 10.2 901 1159 5 L01 Sub 804 34.1 448 1159 8 L Pod Past 1029 21.8 806 1628 14

SBI, mid (Hz) L04 Mat 859 16.8 694 960 3 L21 Mat 1119 33.1 654 1536 5 L01 Sub 1022 31.3 654 1536 8 L Pod Past 2356 14.8 1515 2669 14

SBI, end (Hz) L04 Mat 1019 21.4 776 1198 3 L21 Mat 1514 58.8 587 2493 5 L01 Sub 1328 54.9 587 2493 8 L Pod Past 2442 15.7 1694 2975 14 HFC (Tone) f, start (Hz) L04 Mat 5130 16.1 4176 5625 3 L21 Mat 5256 9.6 4685 5791 5 L01 Sub 5208 11.3 4176 5791 8 L Pod Past 4388 17.6 3064 5546 14 f, level part L04 Mat 5912 2.9 5727 6058 3 (Hz) L21 Mat 5742 1.3 5625 5804 5 L01 Sub 5806 2.4 5625 6058 8 L Pod Past 5798 7.6 4961 6579 14 f, end (Hz) L04 Mat 5920 2.8 5727 6038 3 L21 Mat 5844 1.1 5755 5912 5 L01 Sub 5872 1.9 5727 6038 8 L Pod Past 5879 7.4 5062 6696 14

Call S31

Measurement Social Group Mean C.V. Min Max n Dur (ms) L21 Mat 435 29.7 200 735 47 L12 Sub 410 23.7 341 478 2 L Pod Pres 434 29.3 200 735 49 L Pod Past 481 26.5 338 738 23

SBI, start (Hz) L21 Mat 281 39.8 115 585 47 L12 Sub 839 27.8 674 1004 2 L Pod Pres 304 52.6 115 1004 49 L Pod Past 148 28.2 62 238 23

SBI, mid (Hz)* L21 Mat 459 31.4 188 766 47 L12 Sub 907 5.8 870 944 2 L Pod Pres 477 35.0 188 944 49 L Pod Past - - - - -

SBI, end (Hz) L21 Mat 599 35.3 266 1117 47 L12 Sub 1735 0.4 1730 1740 2 L Pod Pres 645 47.7 266 1740 49 L Pod Past 706 27.6 382 1073 23

Note. *Added measurement; not included in original assessment.

Call S33

Measurement Social Group Mean C.V. Min Max n Dur (ms) L21 Mat 506 6.5 437 545 9 L Pod Past 566 20.4 440 825 14 Part 1 Dur (ms) L21 Mat 89 26.7 61 123 9 L Pod Past 166 21.5 93 239 15 Part 2 Dur (ms) L21 Mat 450 7.2 401 499 9 L Pod Past 396 27.0 299 654 14

Dur, lo part L21 Mat 89 29.3 43 43 11 (ms) L Pod Past 66 25.7 29 108 34

Dur, hi part L21 Mat 124 19.5 109 250 9 (ms) L Pod Past 85 18.5 44 107 24 f, hi part (Hz) L21 Mat 1822 10.2 1328 2328 18 L Pod Past 1695 6.7 1470 1869 34 f, lo part (Hz) L21 Mat 529 19.5 404 779 11 L Pod Past 866 18 556 1099 37

Call S36

Part 1 Part 2 ______

Measurement Social Group Mean C.V. Min Max n Dur (ms) L12 Mat - - - - - L Pod Past 951 11.0 750 1135 21 Part 1 Dur (ms) L12 Mat - - - - - L Pod Past 302 12.7 223 378 28

SBI, start (Hz) L12 Mat - - - - - L Pod Past 900 6 779 981 28

SBI, end (Hz) L12 Mat - - - - - L Pod Past 848 6.7 750 955 28 Part 2 Dur (ms) L12 Mat - - - - - L Pod Past 324 20.3 200 443 19

SBI start (Hz) L12 Mat - - - - - L Pod Past 333 16.4 244 452 21

SBI, end (Hz) L12 Mat - - - - - L Pod Past 214 38.8 86 402 21

Dur (ms) L12 Mat - - - - - L Pod Past 932 11.6 722 1182 28 HFC (Tone) Dur (ms) L12 Mat - - - - - L Pod Past 932 11.6 722 1182 28

Call S36 (continued).

Measurement Social Group Mean C.V. Min Max n f, start (Hz) L12 Mat - - - - - L Pod Past 4751 9.5 3469 5485 27 f, peak (Hz) L12 Mat - - - - - L Pod Past 5847 5.9 5371 6603 27 f, min (Hz) L12 Mat - - - - - L Pod Past 3847 7.3 3441 4394 27 f, end (Hz) L12 Mat - - - - - L Pod Past 5439 2.8 5128 5719 28

Note. Two call were identified in the present study, but were too poor in quality to measure. This spectrogram was pulled from a mixed pod recording for representation.

Call S40

Part 1 Part 2 ______

Measurement Social Group Mean C.V. Min Max n Dur (ms) L12 Mat - - - - - L Pod Past 601 14.6 515 843 18 Part 1 Dur (ms) L12 Mat - - - - - L Pod Past 111 34.5 19 205 18

IPI, start (Hz) L12 Mat - - - - - L Pod Past 17 30.8 5 26 18 Part 2 Dur (ms) L12 Mat - - - - - L Pod Past 490 15.1 410 679 18

SBI, start (Hz) L12 Mat - - - - - L Pod Past 580 13.0 421 661 18

SBI, peak L12 Mat - - - - - (Hz) L Pod Past 1118 9.9 705 1223 18

SBI, mid (Hz) L12 Mat - - - - - L Pod Past 659 11.9 511 770 18

SBI, end (Hz) L12 Mat - - - - - L Pod Past 283 14.3 206 345 18

Note. Two call were identified in the present study, but were too poor in quality to measure. This spectrogram was pulled from a mixed pod recording for representation.

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