• 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.
    • Consequences of maternal effects on offspring size, growth and survival in the desert tortoise

      Nafus, Melia G.; Todd, B. D.; Buhlmann, K. A.; Tuberville, T. D. (2015)
      Here, we examined the relationship between hatchling and maternal body size in the Mojave Desert tortoise Gopherus agassizii. Our results suggest that, in desert tortoises, maternal body size may indirectly influence offspring fitness via growth and survival for at least the first year of life….
    • Hiding in plain sight: a study on camouflage and habitat selection in a slow-moving desert herbivore

      Nafus, Melia G.; Germano, Jennifer M.; Perry, Jeanette A.; Todd, Brian D.; Walsh, Allyson; Swaisgood, Ronald R. (2015)
    • Photos provide information on age, but not kinship, of Andean bear

      Van Horn, Russell C.; Zug, Becky; Appleton, Robyn D.; Velez-Liendo, Ximena; Paisley, Susanna; LaCombe, Corrin (2015)
      Using photos of captive Andean bears of known age and pedigree, and photos of wild Andean bear cubs <6 months old, we evaluated the degree to which visual information may be used to estimate bears’ ages and assess their kinship. We demonstrate that the ages of Andean bear cubs ≤6 months old may be estimated from their size relative to their mothers with an average error of <0.01 ± 13.2 days (SD; n = 14), and that ages of adults ≥10 years old may be estimated from the proportion of their nose that is pink with an average error of <0.01 ± 3.5 years (n = 41). We also show that similarity among the bears’ natural markings, as perceived by humans, is not associated with pedigree kinship among the bears (R2 < 0.001, N = 1,043, p = 0.499). Thus, researchers may use photos of wild Andean bears to estimate the ages of young cubs and older adults, but not to infer their kinship. Given that camera trap photos are one of the most readily available sources of information on large cryptic mammals, we suggest that similar methods be tested for use in other poorly understood species.
    • Polar bear ( Ursus maritimus ) migration from maternal dens in western Hudson Bay

      Yee, Meredith; Reimer, Jody; Lunn, Nicholas J.; Togunov, Ron R.; Pilfold, Nicholas W.; McCall, Alysa G.; Derocher, Andrew E. (2017)
      Migration is a common life history strategy among Arctic vertebrates, yet some of its aspects remain poorly described for some species. In February-March, post-parturient polar bears (Ursus maritimus) in western Hudson Bay, Canada, migrate from maternity den sites on land to the sea ice with three- to four-month-old cubs....