Recent

PUBLICATIONS

Research

PUBLICATIONS

The following is a list of many of the CWR publications. New articles are added once available.

RECENT RESEARCH
Age and sex influence

social interactions,

but not associations,

within a killer whale pod

 Weiss, M. N., Franks, D. W., Giles, D. A., Youngstrom, S., Wasser, S. K., Balcomb, K. C., Ellifrit, D. K., Domenici, P., Cant, M. A., Ellis, S., Nielsen, M. L. K., Grimes, C., and Croft, D. P.

(2021). Age and sex influence social interactions, but not associations, within a killer whale pod.
Proceedings of the Royal Society B,

Volume 288 Issue 1953. 

 

Abstract

Social structure is a fundamental aspect of animal populations. In order to understand the function and evolution of animal societies, it is important to quantify how individual attributes, such as age and sex, shape social relationships. Detecting these influences in wild populations under natural conditions can be challenging, especially when social interactions are difficult to observe and broad-scale measures of association are used as a proxy. In this study, we use unoccupied aerial systems to observe association, synchronous surfacing, and physical contact within a pod of southern resident killer whales (Orcinus orca). We show that interactions do not occur randomly between associated individuals, and that interaction types are not interchangeable. While age and sex did not detectably influence association network structure, both interaction networks showed significant social homophily by age and sex, and centrality within the contact network was higher among females and young individuals. These results suggest killer whales exhibit interesting parallels in social bond formation and social life histories with primates and other terrestrial social mammals, and demonstrate how important patterns can be missed when using associations as a proxy for interactions in animal social network studies.

Mixture models as a method for comparative sociality: social networks and demographic change in resident killer whales

 Ellis, S., Franks, D. W., Weiss, M. N., Cant, M. A., Domenici, P., Balcomb, K. C., Ellifrit, D. K. and Croft, D. P. (2021) Mixture models as a method for comparative sociality: social networks and demographic change in resident killer whales.
Behavioral Ecology and Sociobiology 75,

Article number: 75. 

 

Abstract

In studies of social behaviour, social bonds are usually inferred from rates of interaction or association. This approach has revealed many important insights into the proximate formation and ultimate function of animal social structures. However, it remains challenging to compare social structure between systems or time-points because extrinsic factors, such as sampling methodology, can also influence the observed rate of association. As a consequence of these methodological challenges, it is difficult to analyse how patterns of social association change with demographic processes, such as the death of key social partners. Here we develop and illustrate the use of binomial mixture models to quantitatively compare patterns of social association between networks. We then use this method to investigate how patterns of social preferences in killer whales respond to demographic change. Resident killer whales are bisexually philopatric, and both sexes stay in close association with their mother in adulthood. We show that mothers and daughters show reduced social association after the birth of the daughter’s first offspring, but not after the birth of an offspring to the mother. We also show that whales whose mother is dead associate more with their opposite sex siblings and with their grandmother than whales whose mother is alive. Our work demonstrates the utility of using mixture models to compare social preferences between networks and between species. We also highlight other potential uses of this method such as to identify strong social bonds in animal populations.

Killer Whales

 

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

Ellis, S., Franks, D. W., Weiss, M. N., Cant, M. A., Domenici, P., Balcomb, K. C.,  Ellifrit, D. K. and Croft, D. P. (2021) Mixture models as a method for comparative sociality: social networks and demographic change in resident killer whales. Behavioral Ecology and Sociobiology 75,

Article number: 75. Full Text.

Weiss, M. N., Franks, D. W., Balcomb, K. C., Ellifrit, D. K., Silk, M. J., Cant, M. A., and Croft, D. P. (2020). Modelling cetacean morbillivirus outbreaks in an endangered killer whale population. Biological Conservation 242: 108398. Full Text.

Nattrass, S., Croft, D. P., Ellis, S., Cant, M. A., Weiss, M. N., Wright, B, M., Stredulinsky, E., Doniol-Valcrozef, T., Ford, J. K. B., Balcomb, K. C., & Franks, D. W. (2019). Postreproductive killer whale grandmothers improve the survival of their grandoffspring. PNAS. Full Text.

Ellis, S., Franks, D. W., Nattrass, S., Currie, T. E., Cant, M. A., Giles, D., Balcomb, K. C., & Croft, D. P. (2018). Analyses of ovarian activity reveal repeated evolution of post-reproductive lifespans in toothed whales. Scientific Reports, 8(1). Full Text.

 

Ford, M. J., Parsons, K. M., Ward, E. J., Hempelmann, J. A.,  Emmons, C. K., Hanson, M. B.,  Balcomb, K. C., & Park, L. K. (2018). Inbreeding in an endangered killer whale population. Animal Conservation 21(5): 423-432. Full Text.

Ellis, S., Franks, D. W., Nattrass, S., Cant, M. A., Bradley, D. L., Giles, D., Balcomb, K. C., & Croft D. P. (2018). Postreproductive lifespans are rare in mammals. Ecology and Evolution 8(5): 2482-2494. Full Text.

 

Fearnbach, H., Durban, J. W., Ellifrit, D. K., & Balcomb, K. C. (2018). "Using aerial photogrammetry to detect changes in body condition of endangered southern resident killer whales." Endangered Species Research 35: 175-180. Full Text.

 

Ellis, S., Franks, D.W., Nattrass, S., Cant, M.A., Weiss, M.N., Giles, D., Balcomb, K.C., & Croft, D.P. (2017). Mortality risk and social network position in resident killer whales: sex differences and the importance of resource abundance. Proceedings of the Royal Society B: Biological Sciences, 284(1865), 20171313-20171313. Full Text.

 

Wasser, S. K., Lundin, J. I., Ayres, K., Seely, E., Giles, D., Balcomb, K., Hempelmann, J., Parsons, K., & Booth, R. (2017). Population growth is limited by nutritional impacts on pregnancy success in endangered Southern Resident killer whales (Orcinus orca). PloS One, 12(6), p.e0179824. Full Text.

 

Croft, D. P., Johnstone, R. A., Ellis, S., Nattrass, S., Franks, D. W., Brent, L. J. N., Mazzi, S., Balcomb, K. C., Ford, J. K. B., & Cant, M. A. (2017). Reproductive conflict and the evolution of menopause in killer whales. Current Biology, 27(2), 298–304. Full Text.

 

Lacy, R. C., Balcomb, K. C., Brent, L. J. N., Croft, D. P., Clark, C. W., & Paquet, P. C. (2016). Report on Population Viability Analysis model investigations of threats to the Southern Resident Killer Whale population from Trans-Mountain Expansion Project. Full Text.

 

Ward, E. J., Dahlheim, M. E., Waite, J. M., Emmons, C. K., Marshall, K. N., Chasco, B. E., & Balcomb, K. C. (2016). Long-distance migration of prey synchronizes demographic rates of top predators across broad spatial scales. Ecosphere, 7(2), e01276. Full Text.

 

Brent, L. J. N., Franks, D. W., Foster, E. A., Balcomb, K. C., Cant, M. A., & Croft, D. P. (2015). Ecological knowledge, leadership, and the evolution of menopause in killer whales. Current Biology25(6), 746–750. Full Text.

 

Cogan, J. (2015). 2015 Whale Sightings in the Salish Sea Central Salish Sea and Puget Sound. Center for Whale Research. Full Document.

 

Croft, D. P., Brent, L. J. N., Franks, D. W., & Cant, M. A. (2015). The evolution of prolonged life after reproduction. Trends in Ecology and Evolution30(7), 407–416. Full Text.

 

Foster, E. A., Franks, D. W., Mazzi, S., Darden, S. K., Balcomb, K. C., Ford, J. K. B., & Croft, D. P. (2012). Adaptive prolonged postreproductive life span in killer whales. Science337(6100), 1313–1313. Full Text.

 

Foster, E. A., Franks, D. W., Morrell, L. J., Balcomb, K. C., Parsons, K. M., van Ginneken, A., & Croft, D. P. (2012). Social network correlates of food availability in an endangered population of killer whales, Orcinus orca. Animal Behaviour, 83, 731–736. Full Text.

 

Fearnbach, H., Durban, J. W., Ellifrit, D. K., & Balcomb, K. C. (2011). Size and long-term growth trends of endangered fish-eating killer whales. Endangered Species Research, 13, 173–180. Full Text.

 

Ford, M. J., Hanson, M. B., Hempelmann, J. A., Ayres, K. L., Emmons, C. K., Schorr, G. S., Baird, R. W., Balcomb, K. C., Wasser, S. K., Parsons, K. M., Balcomb-Bartok, K. (2011). Inferred paternity and male reproductive success in a killer whale (Orcinus orca) population. Journal of Heredity102(5), 537–553. Full Text.

 

Ford, J. K. B., Ellis, G. M., Olesiuk, P. F., & Balcomb, K. C. (2010). Linking killer whale survival and prey abundance: food limitation in the oceans’ apex predator? Biology Letters, 6(1), 139–142. Full Text.

 

Parsons, K. M., Balcomb, K. C., Ford, J. K. B., & Durban, J. W. (2009). The social dynamics of southern resident killer whales and conservation implications for this endangered population. Animal Behaviour, 77(4), 963–971. Full Text.

 

Ward, E. J., Holmes, E. E., & Balcomb, K. C. (2009). Quantifying the effects of prey abundance on killer whale reproduction. Journal of Applied Ecology, 46(632–640). Full Text.

 

Ward, E. J., Parsons, K., Holmes, E. E., Balcomb Iii, K. C., & Ford, J. K. (2009). The role of menopause and reproductive senescence in a long-lived social mammal. Frontiers in Zoology, 6(4). Full Text.

 

Dahlheim, M. E., Schulman-Janiger, A., Black, N., Ternullo, R., Ellifrit, D., & Balcomb, K. C. (2008). Eastern temperate North Pacific offshore killer whales (Orcinus orca): Occurrence, movements, and insights into feeding ecology. Marine Mammal Science, 24(3), 719–729. Full Text.

 

Durban, J. W., & Parsons, K. M. (2006). Laser-metrics of free-ranging killer whales. Marine Mammal Science, 22(3), 732–743. Full Text.

 

Ford, J. K. B., & Ellis, G. M. (2005). Prey selection and food sharing by fish-eating “resident” killer whales (Orcinus orca) in British Columbia. Report to Fisheries and Oceans Canada. Full Text.

 

Ford, J. K. B., Ellis, G. M., Matkin, D. R., Balcomb, K. C., Briggs, D., & Morton, A. B. (2005). Killer whale attacks on minke whales: Prey capture and antipredator tactics. Marine Mammal Science, 21(4), 603–618. Full Text.

 

Ford, J. K. B., Ellis, G. M., & Olesiuk, P. F. (2005). Linking prey and population dynamics: did food limitation cause recent declines of “resident” killer whales (Orcinus orca) in British Columbia? Report to Fisheries and Oceans Canada. Full Text.

 

Gaydos, J. K., Balcomb, K. C., Osborne, R. W., & Dierauf, L. (2004). Evaluating potential infectious disease threats for southern resident killer whales, Orcinus orca: A model for endangered species. Biological Conservation, 117, 253–262. Full Text.

 

Krahn, M. M., Wade, P. R., Kalinowski, S. T., Dahlheim, M. E., Taylor, B. L., Hanson, M. B., Ylitalo, G. M., Angliss, R. P., Stein, J. E., & Waples, R. S. (2002). Status Review of Southern Resident Killer Whales (Orcinus orca) under the Endangered Species Act. NOAA Technical Memorandum NMFS Series. Full Text.

 

Ford, J. K. B., Ellis, G. M., & Balcomb, K. C. (2000). Killer Whales: The natural history and genealogy of Orcinus orca in British Columbia and Washington State, Second Edition. Vancouver, BC: UBC Press. 

 

Ford, J. K. B., Ellis, G. M., Barrett-Lennard, L. G., Morton, A. B., Palm, R. S., & Balcomb, K. C. (1998). Dietary specialization in two sympatric populations of killer whales (Orcinus orca) in coastal British Columbia and adjacent waters. Canadian Journal of Zoology, 76, 1456–1471. Full Text.

 

Dahlheim, M. E., Ellifrit, D. K., & J. D. Swenson. (1997). Killer whales of southeast Alaska: A catalogue of photo-identified individuals. 

 

Brault, S., & Caswell, H. (1993). Pod-specific demography of killer whales (Orcinus orca). Ecology, 74(745), 1444–1454. Full Text.

 

Bigg, M. A. (1990). Social organization and genealogy of resident killer whales (Orcinus orca) in the coastal waters of British Columbia and Washington State. In P. Hammond, S. Mizroch, & G. Donovan (Eds.), Individual Recognition of Cetaceans: Use of Photo-Identification and Other Techniques to Estimate Population Parameters (pp. 383–405). Cambridge. 

 

Olesiuk, P. F., Bigg, M. A., & Ellis, G. M. (1990). Life history and population dynamics of resident killer whales (Orcinus orca) in the coastal waters of British Columbia and Washington State. In P. S. Hammond, S. A. Mizroch, & G. P. Donovan (Eds.), Individual Recognition of Cetaceans: Use of Photo-Identification and Other Techniques to Estimate Population Parameters (pp. 209–243). Cambridge. 

 

Bigg, M. A. (1987). Killer Whales: A Study of Their Identification, Genealogy and Natural History in British Columbia and Washington State. Nanaimo: Phantom Press. 

 

Balcomb, K. C., & Bigg, M. A. (1986). Population biology of three resident killer whale pods in Puget Sound and off southern Vancouver Island. In B. C. Kirkevold & J. S. Lockard (Eds.), Behavioral Biology of Killer Whales (pp. 85–95). Alan R. Liss, Inc. 

 

Heimlich-Boran, J. R. (1986). Behavioral ecology of killer whales (Orcinus orca) in the Pacific Northwest. Canadian Journal of Zoology, 66, 565–578. Full Text.

 

Dolphins

 

Fearnbach, H., Durban, J., Parsons, K., & Claridge, A. D. (2012). Photographic mark–recapture analysis of local dynamics within an open population of dolphins. Ecological Applications, 22(5), 1689–1700. Full Text.

 

Fearnbach, H., Durban, J., Parsons, K., & Claridge, D. (2012). Seasonality of calving and predation risk in bottlenose dolphins on Little Bahama Bank. Marine Mammal Science, 28(2), 402–411.

 

Parsons, K. M., Durban, J. W., Claridge, D. E., Herzing, D. L., Balcomb, K. C., & Noble, L. R. (2006). Population genetic structure of coastal bottlenose dolphins (Tursiops truncatus) in the northern Bahamas. Marine Mammal Science, 22(2), 276–298. Full Text.

 

Parsons, K. M., Durban, J. W., Claridge, D. E., Balcomb, K. C., Noble, L. R., & Thompson, P. M. (2003). Kinship as a basis for alliance formation between male bottlenose dolphins, Tursiops truncatus, in the Bahamas. Animal Behavior, 66, 185–194.

 

Parsons, K. M. (2001). Reliable microsatellite genotyping of dolphin DNA from faeces. Molecular Ecology Notes, 1, 341–344.

 

Durban, J. W., Parsons, K. M., Claridge, D. E., & Balcomb, K. C. (2000). Quantifying Dolphin Occupancy Patterns. Marine Mammal Science, 16(4), 825–828.

 

Parsons, K. M., Dallas, J. F., Claridge, D. E., Durban, J. W., Balcomb, K. C., Thompson, P. M., & Noble, L. R. (1999). Amplifying dolphin mitochondrial DNA from faecal plumes. Molecular Ecology, 8, 1753–1768.

 

Claridge, D. E. (1994). Photo-identification study to assess the population size of Atlantic bottlenose dolphins in central Abaco. Bahamas. Journal of Science, 1, 12–16.

 

Humpback Whales

 

Calambokidis, J., Steiger, G., Straley, J., Herman, L., Cerchio, S., Salden, D., Urban R., J., Jacobsen, J., von Ziegesar, O., Balcomb, K. C., Gabriele, C., Dahlheim, M., Uchida, S., Ellis, G., Miyamura, Y., de Guevara P., P. L., Yamaguchi, M., Sato, F., Mizroch, S., Schlender, L., Barlow, J., & Quinn II, T. (2001). Movements and population structure of humpback whales in the North Pacific. Marine Mammal Science, 17(4), 769–794.

 

Calambokidis, J., Steigerl, G. H., Rasmussenl, K., Urban, J. R., Ladron de Guevara, P. P., Salinas, M., Jacobsen, J. K., Scott Baker, C., & Herman, L. M. (2000). Migratory destinations of humpback whales that feed off California, Oregon and Washington. Marine Ecology Progress Series, 192, 295–304.

 

Urban, J., Alvarez, C., Salinas, M., Jacobsen, J., Balcomb, K. C., Jaramillo, A., de Guevara, P. L., & Aguayo, A. (1999). Population size of humpback whale, Megaptera novaeangliae, in waters off the Pacific coast of Mexico. Fishery Bulletin, 97, 1017–1024.

 

Calambokidis, J., Steiger, G. H., Evenson, J. R., Flynn, K. R., Balcomb, K. C., Claridge, D. E., Bloedel, P., Straley, J.M., Baker, C.S., von Ziegesar, O., Dahlheim, M. E., Waite, J. M., Darling, J. D., Ellis, G., & Green, G. (1996). Interchange and isolation of humpback whales off California and other North Pacific feeding grounds. Marine Mammal Science, 12(2), 215–226.

 

Darling, J. D., Calambokidis, J., Balcomb, K. C., Bloedel, P., Flynn, K., Mochizuki, A., Mori, K., Sato, F., Suganuma, H., & Yamaguchi, M. (1996). Movement of a humpback whale (Megaptera novaeangliae) from Japan to British Columbia and return. Marine Mammal Science, 12(2), 281–287.

 

Steiger, G., Calambokidis, J., Sears, R., Balcomb, K. C., & Cubbage, J. (1991). Movement of humpback whales between California and Costa Rica. Marine Mammal Science,7(3), 306–310.

 

Calambokidis, J., Cubbage, J. C., Steiger, G. H., Balcomb, K. C., & Bloedel, P. (1990). Population estimates of humpback whales in the Gulf of the Farralones, California. In P. S. Hammond, S. A. Mizroch, & G. P. Donovan (Eds.), Individual Recognition of Cetaceans: Use of Photo-Identification and Other Techniques to Estimate Population Parameters (pp. 325–328). Cambridge.

 

Blue Whales

 

Calambokidis, J., Steiger, G. H., Cubbage, J. C., Balcomb, K. C., Ewald, C., Kruse, S., Wells, R., & Sears, R. (1990). Sightings and movements of blue whales off central California 1986-1988 from photo-identification of individuals. In P. S. Hammond, S. A. Mizroch, & G. P. Donovan (Eds.), Individual Recognition of Cetaceans: Use of Photo-Identification and Other Techniques to Estimate Population Parameters (pp. 343–349). Cambridge

 

Beaked Whales

 

Cox, T. M., Ragen, T. J., Read, A. J., Vos, E., Baird, R. W., Balcomb, K. C., Barlow, J., Caldwell, J., Cranford, T., Crum, L., D’amico, A., D’Spain, G., Fernandez, A., Finneran, J., Gentry, R., Gerth, W., Gullands, F., Hilderbrand, J., Houserp, D., Hullar, T., Jepson, P. D., Ketten, D., Macleod, C. D., Miller, P., Moore, S., Mountain, D. C., Palka, D., Ponganis, P., Rommel, S., Rowles, T., Taylor, B., Tyack, P., Wartzok, D., Gisiner, R., Meads, J., & Benner, L. (2006). Understanding the impacts of anthropogenic sound on beaked whales. Journal of Cetacean Resource Management, 7(3), 177–187.

 

General Cetaceans

 

Durban, J. W., Elston, D. A., Ellifrit, D. K., Dickson, E., Hammond, P. S., & Thompson, P. M. (2005). Multi-site mark-recapture for cetaceans: population estimates with Bayesian model averaging. Marine Mammal Science, 2(1), 80–92.

 

Durban, J. W., & Elston, D. A. (2005). Mark–recapture with occasion and individual effects: abundance estimation through bayesian model selection in a fixed dimensional parameter space. Journal of Agricultural, Biological and Environmental Statistics,10(3), 291–305. Full Text.

 

Parsons, K. M., & Durban, J. W. (2003). Comparing two alternative methods for sampling small cetaceans for molecular analysis. Marine Mammal Science, 19(1), 224–231.