Edward O. Minot

Stallion harassment and the mating system of horses

Feral horse, Equus caballus, breeding groups, called bands, usually include one but sometimes up to five stallions. We found that mares were loyal to single-stallion (SS) or multistallion (MS) bands or were social dispersers (maverick mares, Mv). The spacing and social behaviour of mares and stallions in single- and multistallion bands was measured. Indices of mare well-being were also measured including activity budgets (feeding: MS>SS=Mv; resting: MS<SS=Mv), band and mare travel (MS>SS), maternal effort in maintaining contact with foals (MS=Mv>SS), parasite levels in faeces (MS>Mv>SS), body condition (MS=Mv<SS), fecundity (Mv<MS<SS) and offspring mortality (Mv<MS<SS). We present evidence suggesting that the poorer well-being of maverick mares and multistallion band mares results from greater harassment by stallions. Stallion and mare behaviour and poor reproductive success in multistallion bands were not consistent with explanations for the existence of such bands based on cooperation or alternative mating strategies. We suggest an alternative explanation. Stable relationships between mares and a single stallion may enhance reproductive success by reducing aggression between individuals. Therefore, we propose that there is strong selection pressure for stable, long-term stallion-mare relationships, called consort relationships. We propose the consort hypothesis, that multistallion bands are an artefact of selection for stable relationships that occasionally result in more than one such relationship forming, because mares solicit more than one stallion and stallion dominance changes during band formation. Copyright 1999 The Association for the Study of Animal Behaviour.

Aging and improving reproductive success in horses: declining residual reproductive value or just older and wiser?

Abstract In many mammalian species, female success in raising offspring improves as they age. The residual reproductive value hypothesis predicts that each individual offspring will be more valuable to the mother as she ages because there is less conflict between the current and potential future offspring. Therefore, as mothers age, their investment into individual offspring should increase. Empirical evidence for an influence of declining residual reproductive value on maternal investment is unconvincing. Older mothers may not invest more, but may be more successful due to greater experience, allowing them to target their investment more appropriately (targeted reproductive effort hypothesis). Most studies do not preclude either hypothesis. Mare age significantly influenced maternal investment in feral horses living on the North Island of New Zealand. Older mares, that were more successful at raising foals, were more protective for the first 20 days of life, but less diligent thereafter. Total maternal input by older mothers did not seem to be any greater, but was better targeted at the most critical period for foal survival and a similar pattern was observed in mares that had lost a foal in the previous year. In addition, older mothers were more likely to foal in consecutive years, supporting the hypothesis that they are investing less than younger mares in individual offspring. Therefore, older mothers seem to become more successful by targeting their investment better due to experience, not by investing more in their offspring.

An olfactory recognition system in the ferret Mustela furo L. (Carnivora: Mustelidae)

Abstract This study demonstrates that ferrets can use variations in odours from anal sac secretions as a communication system. Odour preference tests showed that ferrets can discriminate between male and female ferret anal sac odours, between strange and familiar, familiar and their own, and fresh and 1-day-old odours. They did not discriminate between fresh and 2-h-old odours, nor did male ferrets discriminate between the odours of oestrous and anoestrous females. Ferrets were more attracted to the odours of the opposite sex than to those of their own sex. When faced by an opponent, male ferrets were more aggressive in the presence of their own rather than their opponents odour, and less aggressive with their opponents odour than with that of a known, dominant animals odour. These results are consistent with both a sex attraction role and a territorial defence role for anal sac odours. A scent-matching mechanism for territorial defence is supported, although a neighbour-neighbour recognition/avoidance mechanism cannot be rejected. Gas chromatography revealed sexually and individually distinct profiles of volatile compounds in anal sac extracts, but no consistent seasonal trends. Females had high concentrations of 2,3-dimethylthietane and/or 3,4-dimethyl-1,2-dithiolane. Males usually had high concentrations of indole. 2-Propylthietane was an important constituent in most individuals. These differences in concentration were significant and could provide an olfactory recognition system of sex and individual identity.

Social grouping and maternal behaviour in feral horses (Equus caballus): the influence of males on maternal protectiveness

Abstract. The risk of infant injury or mortality influences maternal behaviour, particularly protectiveness. Mares are found in bands with a single stallion or bands with more than one stallion in which paternity is less certain. We investigated maternal behaviour in relation to band type. Mares in bands with more than one stallion were more protective of their foals, particularly when stallions and foals approached one another. The rate of aggression between the stallion and foal was a significant predictor of maternal protectiveness, and mare protectiveness was significantly correlated with reduced reproductive success in the subsequent year. Mares that changed band types with a foal at foot, or had their band type experimentally altered, were more protective of their foal in multi-stallion bands than they were in single-stallion bands. Equids are unusual amongst ungulates in that infanticide and feticide have been reported. Both occur where paternity has been uncertain, and equid social structure is similar to other species in which infanticide has been reported. Stallions benefit from infanticide as the mare has greater reproductive success in the subsequent year. Stallion aggression is a significant modifier of mare behaviour and maternal effort, probably due to the risk of infanticide.

Maternal investment results in better foal condition through increased play behaviour in horses

Play behaviour is widespread in mammals, but benefits to play have been difficult to demonstrate. Physical training is one of the many proposed hypotheses, suggesting that males and females should play differently, that increased maternal investment should lead to increases in play, and that increases in play should result in physical advantages. In a population of feral horses, Equus caballus, males and females did not differ in their play behaviour except that males initiated more of their play bouts than females. Maternal condition influenced play behaviour only in males, with sons of mothers in good condition playing more. However, when we controlled for maternal effects by comparing a son and a daughter of the same mother, daughters played more when their mother was in poor condition and sons played more when their mother was in good condition. Mothers of foals that played more lost more condition. Therefore, the difference in play behaviour could not be explained by offspring sex or maternal condition alone, but play behaviour mirrored variation in maternal investment. In addition, those individuals that played more survived better and had better body condition as yearlings despite weaning earlier. Since increased activity has been linked to enhanced musculoskeletal development in domestic horses, we suggest that play provides a link between increased maternal investment, increased body condition and future reproductive success in feral horses, and probably in other species.

Minisatellite DNA profiling detects lineages and parentage in the endangered kakapo (Strigops habroptilus) despite low microsatellite DNA variation

An important goal of the conservationmanagement program of the critically endangeredground parrot, the New Zealand kakapo (Strigops habroptilus) is the determination ofparentage and levels of genetic diversitywithin the remaining population. Our previousmicrosatellite DNA studies have shown that allindividuals of this species except one arehomozygous at seven loci examined. Incontrast, we now show that a minisatellite DNAanalysis of kakapo provides sufficientvariation to conduct paternity analyses anddetect heterogeneity within the 86 livingkakapo. The sole remaining Fiordland kakapo,Richard Henry, is shown to be geneticallydivergent from individuals originating from theonly other remaining population on StewartIsland, suggesting that two lineages of kakapoare present in the extant population. This hasparticular significance for the conservationmanagement goal of maintenance of the maximumgenetic diversity in the species as a whole. The example of the kakapo illustrates thatminisatellite DNA markers can be useful incases where microsatellite DNA fails to showsufficient variation.

Rodent and predator population dynamics in an eruptive system

A computer model of the population dynamics of introduced house mice (Mus musculus L.), ship rats (Rattus rattus L.) and stoats (Mustela erminea L.) in New Zealand forest was constructed, to test the relative importance of food availability and predation in shaping observed small-mammal population dynamics. Ship rats and mice are the two common rodent species present in most New Zealand forests, and exhibit eruptive population dynamics. Stoats are the only common mammalian predator, and undergo large density fluctuations following periodic rodent eruptions. A number of outputs and predictions from the model were developed. The model highlights the overall importance of variation in food availability in determining the timing and amplitude of rodent population eruptions. It indicates that predators can not prevent a prey–species eruption, primarily due to differences in reproductive biology. Predation however, can delay the start of the prey-population increase during the eruption. The role of predators in limiting the peak prey-population size will depend on the size of the energy input. In a full-scale eruption following maximal tree seeding, predators cannot significantly truncate peak prey-population size. Predators should be able to significantly hasten the rate of decline in the prey populations, although the strength of predator limitation will depend on the severity of food limitation and cold-induced mortality over the same period. Predators can limit prey populations during the post-crash low phase. As with the crash phase, the strength of predator limitation in the low phase will depend on the severity of food limitation and natural mortality. The model highlights gaps in current knowledge of predator and prey species biology and ecology. The model highlights key areas where further field study should provide a better understanding of the factors driving small-mammal communities in New Zealand.

Elephant (Loxodonta africana) Home Ranges in Sabi Sand Reserve and Kruger National Park: A Five-Year Satellite Tracking Study

During a five-year GPS satellite tracking study in Sabi Sand Reserve (SSR) and Kruger National Park (KNP) we monitored the daily movements of an elephant cow (Loxodonta africana) from September 2003 to August 2008. The study animal was confirmed to be part of a group of seven elephants therefore her position is representative of the matriarchal group. We found that the study animal did not use habitat randomly and confirmed strong seasonal fidelity to its summer and winter five-year home ranges. The cows summer home range was in KNP in an area more than four times that of her SSR winter home range. She exhibited clear park habitation with up to three visits per year travelling via a well-defined northern or southern corridor. There was a positive correlation between the daily distance the elephant walked and minimum daily temperature and the elephant was significantly closer to rivers and artificial waterholes than would be expected if it were moving randomly in KNP and SSR. Transect lines established through the home ranges were surveyed to further understand the fine scale of the landscape and vegetation representative of the home ranges.

The experience of dog bites: A survey of veterinary science and veterinary nursing students

Abstract AIM: To investigate the circumstances of dogs biting people in New Zealand. METHODS: Veterinary science and veterinary nursing students enrolled at Massey University in 2003 completed a questionnaire detailing their lifetime experience of dog bites and their opinions of dog control legislation. RESULTS: The response rate was 100%. There were 228 completed responses to the survey, and 87 (38%) respondents had been bitten by a dog. Most bites caused minor injury, but 17 (20%) required medical attention. Male respondents were more likely to have been bitten. The highest proportion of respondents (27; 31%) had been bitten while between 6 and 10 years of age, and the hand was the part of the body most often injured. Eighteen (21%) bites involved a strangers dog, but most bites were by a dog known to the victim. Respondents from rural areas were three times more likely to have been bitten than city dwellers. The victims home was the place where most (31; 36%) bites occurred. Male dogs were responsible for a larger proportion of bites (38; 44%) than females (24; 28%); respondents were unsure about the sex of the remainder of the dogs (25; 29%) that bit them. Protecting the home, play, accidents, rough handling and pain were identified as the common reasons for dogs to bite. Most (46; 52%) respondents did not believe legislation could have prevented their bite. Only four (5%) bites were reported to authorities. CONCLUSION: Rural dwellers, people with more experience of dogs, children <11 years of age, and male respondents were bitten by dogs most often. Only legislation relating to the fencing of dog owners′ properties may have prevented a reasonable proportion (25; 29%) of the bites reported here.

Distribution and abundance of forest birds in the Ruamahanga ecological area, North Island, New Zealand

Abstract Relationships between forest structure and avian communities have been documented in many northern temperate and tropical studies. This study tests the applicability of conclusions from those studies to New Zealand forest bird communities. For 29 months from September 1982 to February 1985 we monitored the bird community in part of the Ruamahanga Ecological Area, Tararua State Forest Park. We used a modified 5 min bird count to determine the relative abundances of each bird species. The modification consisted of separating the counts into birds near to ( 20 m) the observer. The near/far ratio proved useful in assessing the distribution of common bird species but was inadequate for rarer species. Twenty‐nine bird species were seen, 21 of which probably bred within the study area. Eleven forest bird species were seen with sufficient frequency to apply the near/far ratio. Principal component analysis was used as a graphical tool to describe the inter‐relationships of bird specie...