Paul K. Anderson’s research while affiliated with University of Calgary and other places

The significance of risk assessment in determining the boundaries of foraging ranges of deer mice and voles was examined by comparing the distances to which resident animals were willing to follow shifting feeding stations providing equal rewards beyond their previous foraging ranges in an area with abundant cover (forest), and in one where cover was lacking (frozen lake surface). Previous foraging ranges were estimated on the basis of livetrapping and the "rediscovery distances" for the moving stations. In three experiments the distance at which animals stopped visiting the stations ("giving-up distance") averaged 3.3 times farther where cover was abundant (forest) than where it was absent (lake). In a fourth experiment, reduction of supplementary food available within the original ranges extended the giving-up distance where cover was present but had relatively little effect on giving-up distance and almost no effect on rediscovery distance where cover was absent. Supplying cover more than tripled giving-up distances on the lake. The distance at which boxes were visited was affected by snowfall, ambient temperature, food supply, and availability of cover. Results emphasize the importance of risk assessment in defining foraging range, and suggest that hoarding permits choice among energy maximization and time minimization strategies.

House mice displaced from established home ranges in grassland on Great Gull Island, New York, exhibited homing behaviour. This behaviour was associated with large home range, wandering before home range establishment, and forays outside the range. When both house mice and deer mice inhabiting granaries in grassland in Alberta were displaced, homing behaviour was poorly expressed in house mice, but well developed in deer mice. The poorly developed homing tendency of Alberta house mice was associated with a pattern of habitat utilization that appeared to limit familiarity with areas outside the home range. While this result does not explicitly eliminate a role for a direction-finding ability in house mouse homing, it does emphasize the importance of familiarity with terrain external to the home range.

Subadult and adult Microtus pennsylvanicus were confined in the field in Longworth live traps which were covered with a cedar shingle for insulation and supplied with rolled oats for food and cotton for nesting. Both groups consistently lost about 10% of their initial body weight during confinement. Adults lost significantly more weight in early May than in mid-June, and adults captured in early May did not regain lost weight as rapidly as adults captured in June or July.

Small egg-like structures from the Upper Cretaceous (Campanian) Djadokhta Formation of Mongolia were previously interpreted as casts of crocodile, lizard, and turtle eggs, or as inorganic nodules. Identical structures from coeval redbeds at Bayan Mandahu in northern China indicate the structures are not vertebrate eggs, nor of vertebrate origin. Comparisons with Recent and Quaternary beetle (Coleoptera) pupal chambers show close similarities in size, shape, and the presence of a round to irregular exit hole for the adult beetle. Most importantly, the Cretaceous structures are enveloped by a thin clay-rich zone, which is expected if constructed by beetle larvae but inexplicable in any egg or inorganic nodule model. Additional evidence contradicting a vertebrate egg origin for the structures includes (i) the structures are too small to have been laid by turtle or crocodile species occurring in the Bayan Mandahu redbeds; (ii) the structures are isolated, not in clutches or pairs; and (iii) unlike newly hatched soft-shelled lizard eggs, the Cretaceous structures are not collapsed and show a round to irregular exit hole rather than a slit. It is concluded that the egg-like structures are sand casts (steinkerns) of beetle pupal chambers, probably of Scarabaeidae, Tenebrionidae, or Curculionidae. The Cretaceous pupal chambers are assigned to a new ichnogenus, Fictovichnus, and new ichnospecies, Fictovichnus gobiensis and Fictovichnus parvus.

Small birds that winter in the tropics and breed in the northern hemisphere migrate at night. When the sky is overcast, particularly with rain or snow in the air, these migrants become attracted to and disoriented by the aircraft warning lights on tall structures. They often die as they strike the structures and supporting wires. Mass mortality events have been repeatedly recorded in the United States over the past half century. Migrants under threat from habitat destruction in their wintering and nesting areas are the most vulnerable. Tall towers are multiplying with the proliferation of cellular telephones and the introduction of digital television. Estimates based on available data in North America imply significant threats at the population level and a review of a recent bibliography suggests an unexplained concentration of risk in the Mississippi and central flyways. The telecommunications industry and the American and Canadian governments (in violation of treaty obligations and applicable regulations) are refusing to accept responsibility, support research, or adopt remedial measures. A brief survey of the international situation conducted by the author indicates tower proliferation worldwide, reports of nocturnal migrant deaths but no indication of government or industry interest or action. Systematic monitoring of mortality at towers is desperately required.

Lek polygyny, monogamy and scramble promiscuity have been reported in the two families and five species of Recent sirenians. Evidence for lek mating in the dugong or "sea pig" (Dugong dugon), monogamy in Steller's sea cow (Hydrodamalis gigas), and scramble promiscuity in the three manatees or "river cows" (Trichechus manatus, Trichechus senegalensis, and Trichechus inunguis), as well as in one dugong population, is reviewed. Sirenians are long-lived "K-strategists" with precocious young, few potential young per female lifetime, high female investment in a few young, little apparent opportunity for post-copulatory male investment, and "paenungulate" reproductive physiologies that appear to increase uncertainty as to female receptivity and assurance as to paternity. Common features notwithstanding, diverse habitats, climates, and niches may account for mating system diversity. Scenarios for evolution of diverse mating systems, based on our understanding of mating systems in terrestrial herbivores, are presented. The dugong retains the ancestral low latitude marine, seagrass dependent, bottom-feeding, niche characteristic of diverse, tusked, Oligocene and Miocene sirenian faunas. With a long breeding season and high polygyny potential, retention of tusks by male dugongs in the absence of any foraging function suggests that tusks may have always had social functions and lekking may be of ancient origin. The sea cow lineage, isolated on the shoreline of the northeastern Pacific as seagrasses declined, turned to surface foraging on chemically undefended kelps and lost both tusks and molar teeth. As it followed kelps northwards, adaptation to a cold-temperate climate compressed the breeding season, limited the polygyny potential, and, in conjunction with incentives for paternal investment, favored pair bonding and the monogamous mating system postulated by George Steller (1751). Manatees, evolving in botanically-rich fresh waters of the Amazon basin as an aberrant offshoot of the marine dugongid line, remained in the tropics and retained a high polygyny potential, but became generalist foragers in the upper few meters of the water column. Labyrinthine river systems provided little opportunity for male aggregation and display (or rhizome foraging) and tusks were lost as the uncertainty of female inseminability drove the mating system toward scramble promiscuity and sperm competition. An observation of manatee-like behavior in a dense and sedentary dugong population in eastern Australia suggests plasticity in sirenian mating, and the likelihood that a form of scramble promiscuity may exist where no suitable site for lekking is available, where large group size makes female defence impossible, or where vulnerability of territorial males to hunting has resulted in extirpation of a lekking tradition. Dugong and manatee life history characteristics conform to expectations based on observed differences in mating systems.

Physical variables, standing crop and dugong activity were monitored over 14 months in a subtidal community dominated by the tropical seagrass Halodule uninervis and the green alga Penicillus nodulosus in a small cove in subtropical Shark Bay, Western Australia. Water temperature ranged from 14.5 (June) to 30.5°C (February), salinity from 48 (August) to 62‰ (March). Attenuation coefficients were 0.18–0.32m−1 in February and 0.10m−1 in June. Mean daily PAR at the sea bed was 200μmolm−2s−1 in September and 400μmolm−2s−1 in January. Visually, Halodule appeared dominant, but Penicillus biomass exceeded Halodule biomass by ≈3% on ridges and averaged ≈ nine times higher in gullies. Total Halodule biomass on ridges was 46.5gm−2 in May and 69.8gm−2 in March, rhizome biomass (40–65gdry weightm−2) was four to six times leaf biomass (7–16gdry weightm−2). Productivity on the ridges, measured over 4–6 week intervals was 0.12gdry weightm−2 per day in August–October and 1.56gdry weightm−2 per day in March–April. Growth persisted throughout the year, and was not limited to temperatures of ≥21°C. Productivity was estimated as 295gdry weightm−2 per year. The plastochrone interval for rhizomes (PIR) was 12.3 days in May and June and 5.9 days in February. The temporal peak in productivity did not coincide with peak insolation, but did coincide with high temperatures and high and continuous dugong activity. Statistical analysis indicated that light and temperature influenced leaf productivity more than they did rhizome, root, or total productivity. Dugongs (Dugong dugon) rooted in the community from January through April, raising levels of suspended sediments and attenuation coefficients and reducing PAR. Halodule biomass in dugong exclosures at the end of the grazing season was 1.8 times that in adjacent unprotected areas. Dugongs departed when autumn temperatures fell below 19°C. During the grazing season loss of biomass resulting from dugong activity exceeded 50% of production.

Marine mammals are a K-selected relict megafauna that escaped the mass extinctions that affected their terrestrial counterparts at the end of the Pleistocene. Over the last 500 years they have been severely impacted as humans have mastered the marine environment. Some stocks and species went to extinction, and extinction of others was narrowly averted through international efforts regulating commercial exploitation. In the late 20th century new threats arose through contamination of the marine environment and these will be exacerbated and added to as human numbers double and economies grow over the next century.