• Age-related patterns of neophobia in an endangered island crow: implications for conservation and natural history

      Greggor, Alison L.; Masuda, Bryce M.; Flanagan, Alison M.; Swaisgood, Ronald R. (2020)
      Theory suggests that the balance between unknown dangers and novel opportunities drives the evolution of species-level neophobia. Juveniles show lower neophobia than adults, within mammals and birds, presumably to help minimize the costs of avoiding beneficial novelty, and adults tend to be more neophobic, to reduce risks and focus on known stimuli. How these dynamics function in island species with fewer dangers from predators and toxic prey is not well understood. Yet, predicting neophobia levels at different age classes may be highly valuable in conservation contexts, such as species' translocation programmes, where responses to novelty can influence the effectiveness of prerelease training and animals' survival postrelease. To better understand how neophobia and its age-related patterns are expressed in an island corvid, we surveyed object neophobia in 84% of the world's critically endangered ‘alal?, Corvus hawaiiensis. Individuals repeatedly demonstrated high neophobia, suggesting that neither captivity nor their island evolution has erased this corvid-typical trait. Unexpectedly, juveniles were exceedingly more neophobic than adults, a pattern in stark contrast to common neophobia predictions and known mammalian and avian studies. We discuss the potential conservation ramifications of this age-structured result within the larger context of neophobia theory. Not only may the expression of neophobia be more complicated than previously thought but predicting such responses may also be important for conservation management that requires exposing animals to novelty.
    • Body size, not phylogenetic relationship or residency, drives interspecific dominance in a little pocket mouse community

      Chock, Rachel Y.; Shier, Debra M.; Grether, Gregory F. (2018)
      The role of interspecific aggression in structuring ecological communities can be important to consider when reintroducing endangered species to areas of their historic range that are occupied by competitors. We sought to determine which species is the most serious interference competitor of the endangered Pacific pocket mouse, Perognathus longimembris pacificus, and more generally, whether interspecific aggression in rodents is predicted by body size, residency status or phylogenetic relatedness....
    • Changes in vocal repertoire of the Hawaiian crow, Corvus hawaiiensis, from past wild to current captive populations

      Tanimoto, Ann M.; Hart, Patrick J.; Pack, Adam A.; Switzer, Richard; Banko, Paul C.; Ball, Donna L.; Sebastián-González, Esther; Komarczyk, Lisa; Warrington, Miyako H. (2017)
      ...We compared the vocal repertoire of three of the last four wild 'alalā pairs from the early 1990s to three current captive pairs on the Island of Hawai'i to determine how acoustic behaviour has been affected by changes in their social and physical environment. Over 18 h of recordings from wild breeding pairs were analysed and compared with 44 h from captive breeding pairs....
    • Chemical signals of age, sex and identity in black rhinoceros

      Linklater, W. L.; Mayer, K.; Swaisgood, Ronald R. (2013)
      Olfactory communication may be particularly important to black rhinoceros, Diceros bicornis, because they are solitary living and have comparatively poor eyesight but their populations are structured by inter-and intrasexual relationships. Understanding olfactory functions and processes might achieve better conservation management but their study in rhinoceros remains anecdotal or descriptive….
    • Lifetime changes in vocal syntactic complexity of rock hyrax males are determined by social class

      Demartsev, Vlad; Kershenbaum, Arik; Ilany, Amiyaal; Barocas, Adi; Weissman, Yishai; Koren, Lee; Geffen, Eli (2019)
      The ontogeny of quality-based signals has been studied in numerous animal systems but the degradation of vocal signals with age has received much less attention. Investigating age-related changes in quality-based acoustic signals and the associated social processes (e.g. rank changes, competition intensity) can expand our understanding of the information content of signals and their perception by receivers....
    • Signalling behaviour is influenced by transient social context in a spontaneously ovulating mammal

      Owen, Megan A.; Swaisgood, Ronald R.; Zhou, Xiaoping; Blumstein, Daniel T. (2016)
      ...Using female giant pandas at the Wolong Breeding Centre in Sichuan, China, we explored the interaction between social context and reproductive status on signalling and maintenance behaviours. To do so, we used linear mixed models and an information-theoretic approach to assess the temporal relationship between signalling behaviours and the timing of first mating....