Animals often form groups to reduce the risk of predation through the per capita dilution of their individual predation risk. The advantages of grouping also influence the timing of reproduction in many species. In particular, synchrony in the timing of births may have evolved as a predator‐avoidance strategy as it dilutes the risk of predation upon vulnerable newborn and naive young. Eggs of an Australian freshwater turtle, Emydura macquarii, can hatch synchronously despite developmental asynchrony among eggs of a clutch and hatchlings have a reduced predation risk by emerging from the nest as a group. Developmental asynchrony within clutches was induced to reflect natural nests by dividing clutches and incubating them at either 25°C or 30°C. Some eggs were then reunited with their clutch‐mates and hatching occurred synchronously in some of these groups. In groups where synchronous hatching did not occur, less advanced eggs still hatched earlier than the normal incubation period. Synchrony occurred because the less advanced eggs hatched up to five days earlier than the control embryos. We conclude that the less advanced embryos within a clutch either accelerate their development or hatch prematurely to ensure synchrony of hatching and hatchling group formation may facilitate emergence from the nest and dilute predation risk.

Introduction: Food availability is an important environmental cue for animals for deciding how much to invest in reproduction, and it ultimately affects population size. The importance of food limitation has been extensively studied in terrestrial vertebrate populations, especially in birds, by experimentally manipulating food supply. However, the factors explaining variation in reproductive decisions in response to food supplementation remain unclear. By performing meta-analyses, we aim to quantify the extent to which supplementary feeding affects several reproductive parameters in birds, and identify the key factors (life-history traits, behavioural factors, environmental factors, and experimental design) that can induce variation in laying date, clutch size and breeding success (i.e., number of fledglings produced) in response to food supplementation. Results: Food supplementation produced variable but mostly positive effects across reproductive parameters in a total of 201 experiments from 82 independent studies. The outcomes of the food effect were modulated by environmental factors, e.g., laying dates advanced more towards low latitudes, and food supplementation appeared not to produce any obvious effect on bird reproduction when the background level of food abundance in the environment was high. Moreover, the increase in clutch size following food addition was more pronounced in birds that cache food, as compared to birds that do not. Supplementation timing was identified as a major cause of variation in breeding success responses. We also document the absence of a detectable food effect on clutch size and breeding success when the target species had poor access to the feed due to competitive interactions with other animals. Conclusions: Our findings indicate that, from the pool of bird species and environments reviewed, extra food is allocated to immediate reproduction in most cases. Our results also support the view that bird species have evolved different life-history strategies to cope with environmental variability in food supply. However, we encourage more research at low latitudes to gain knowledge on how resource allocation in birds changes along a latitudinal gradient. Our results also emphasize the importance of developing experimental designs that minimise competition for the supplemented food and the risk of reproductive bottle-necks due to inappropriate supplementation timings.

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Managing vertebrate pests is a global conservation challenge given their undesirable socio-ecological impacts. Pest management often focuses on the 'average' individual, neglecting individual-level behavioural variation ('personalities') and differences in life histories. These differences affect pest impacts and modify attraction to, or avoidance of, sensory cues. Strategies targeting the average individual may fail to mitigate damage by 'rogues' (individuals causing disproportionate impact) or to target 'recalcitrants' (individuals avoiding standard control measures). Effective management leverages animal behaviours that relate primarily to four core motivations: feeding, fleeing, fighting, and fornication. Management success could be greatly increased by identifying and exploiting individual variation in motivations. We provide explicit suggestions for cue-based tools to manipulate these four motivators, thereby improving pest management outcomes.Looking Beyond the 'Average' Individual in Vertebrate Pest Management Vertebrate pests, including invasive or overabundant predators and herbivores, frequently come into conflict with economic, social, and biodiversity values. Mammalian predators are responsible for some of the most devastating losses to native biodiversity [1] and frequently harm humans, their livestock, and pets, while herbivores can cause agricultural damage, vehicle collisions, and ecosystem-level impacts including overbrowsing [2,3]. Mitigating the impacts of vertebrate pests thus presents one of the major challenges currently facing wildlife managers. Managers require effective strategies to: (i) reduce pest populations (e.g., by attracting individuals to traps or toxic baits), and (ii) deter individuals from sensitive areas or valuable species (e.g., threatened prey or plant species, livestock, agricultural, and forestry sites). Yet, pest control measures are often only partially effective [4,5], with some individuals avoiding lethal control or ignoring deterrents. Attractants and deterrents typically target the 'average' individual in a population, with the goal of maximising the number of animals responding to stimuli. However, the most intractable challenges of vertebrate pest management may occur precisely because some individuals do not behave like the average, and therefore, are not effectively targeted.Within a pest population, individuals exhibit a range of responses to management actions. Deviations from the average response may be transient (e.g., dependent on internal state, body condition, current perceived risk, or density of conspecifics) [6], or may represent persistent, individual-level behavioural differences ('personalities') [7,8]. By understanding the drivers of individual-level differences in behaviour, management can be optimized to target not just the average individual, but the full range of behavioural types within a population. Such insights may be particularly valuable in managing rogue and recalcitrant individuals (see Glossary), two non-exclusive behavioural types t...

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We used a food-supplementation experiment to test the hypothesis that small-mammal populations are food-limited during winter in southeastern Australia. We trapped small mammals along 120- to 150-m transects at 12 creek and 12 ridgetop sites (representing high- and low-quality habitats) for 2 months prior to winter and 2 months during winter. High-quality food (peanut butter, honey, oats, and dried cat food) was provided ad libitum for 7 weeks during winter at four sites in each habitat. Eight sites were provided with empty feeding tubes and eight were untreated. Seven weeks of food supplementation caused numerical increases of 4.0- and 5.0-fold for the rodents Rattus fuscipes and Rattus lutreolus, respectively. Increases were due largely to immigration, and were only observed in the high-quality creek habitats (R. lutreolus were exclusively captured at creek sites). Food supplementation also led to an increase in body mass and reversed the hiatus in winter breeding for rodents. These results suggest that populations of both species are limited by winter food availability. However, survival rates (indexed from recapture rates) were not affected by food supplementation. Mean body mass of the marsupial Antechinus stuartii also increased with food supplementation, but other demographic parameters showed no response; numbers declined at creek sites after additional food was provided. Trapping-revealed measures of interspecific association showed that A. stuartii avoided areas of high rat numbers after additional food was provided. It is thus likely that interference competition from the much larger and more abundant rodents forced A. stuartii out of the food-supplemented creek sites, hence mediating the direct effects of food supplementation on this species.

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