Animal tracking data are being collected more frequently, in greater detail, and on smaller taxa than ever before. These data hold the promise to increase the relevance of animal movement for understanding ecological processes, but this potential will only be fully realized if their accompanying location error is properly addressed. Historically, coarsely-sampled movement data have proved invaluable for understanding large scale processes (e.g., home range, habitat selection, etc.), but modern fine-scale data promise to unlock far more ecological information. While location error can often be ignored in coarsely sampled data, fine-scale data require much more care, and tools to do this have been lacking. Current approaches to dealing with location error largely fall into two categories—either discarding the least accurate location estimates prior to analysis or simultaneously fitting movement and error parameters in a hidden-state model. Unfortunately, both of these approaches have serious flaws. Here, we provide a general framework to account for location error in the analysis of animal tracking data, so that their potential can be unlocked. We apply our error-model-selection framework to 190 GPS, cellular, and acoustic devices representing 27 models from 14 manufacturers. Collectively, these devices are used to track a wide range of animal species comprising birds, fish, reptiles, and mammals of different sizes and with different behaviors, in urban, suburban, and wild settings. Then, using empirical data on tracked individuals from multiple species, we provide an overview of modern, error-informed movement analyses, including continuous-time path reconstruction, home-range distribution, home-range overlap, speed and distance estimation. Adding to these techniques, we introduce new error-informed estimators for outlier detection and autocorrelation visualization. We furthermore demonstrate how error-informed analyses on calibrated tracking data can be necessary to ensure that estimates are accurate and insensitive to location error, and allow researchers to use all of their data. Because error-induced biases depend on so many factors—sampling schedule, movement characteristics, tracking device, habitat, etc.—differential bias can easily confound biological inference and lead researchers to draw false conclusions.

In cooperatively breeding species, the level of investment in young can vary substantially. Despite receiving considerable research attention, how and why investment in young varies with cooperatively breeding group members remains unclear. To investigate the causes of variation in care of young, we assessed patterns of both helper and parental behavior in the cooperatively breeding Western Australian magpie (Cracticus tibicen dorsalis). Observations of 19 helpers and 31 parents provisioning 33 broods raised in 11 different groups over two consecutive breeding seasons revealed substantial variation in offspring care behavior. Our results suggest that the level of investment in young by helpers is strongly influenced by group size, chick age, and individual helper traits (including foraging efficiency, age and sex). Helping behavior was facultative, and individuals from smaller groups were more likely to invest in helping behavior. Overall, the number of broods receiving help was lowest during the nestling phase and highest during the fledgling phase. Female helpers provided more care than both male and juvenile helpers. We found that mothers invest more time in offspring care than do fathers, however fathers increase their effort in the presence of helpers while mothers do not. Overall, helper care was additive to parental care and therefore helping behavior may be beneficial to the brood. Our research reveals that variation in offspring care in magpies is influenced by both social and individual traits.

Alternative reproductive tactics, whereby members of the same sex use different tactics to secure matings, are often associated with conditional intrasexual dimorphisms. Given the different selective pressures on males adopting each mating tactic, intrasexual dimorphism is more likely to arise if phenotypes are genetically uncoupled and free to evolve towards their phenotypic optima. However, in this context, genetic correlations between male morphs could result in intralocus tactical conflict (ITC). We investigated the genetic architecture of male dimorphism in bulb mites (Rhizoglyphus echinopus) and earwigs (Forficula auricularia). We used half-sibling breeding designs to assess the heritability and intra/intersexual genetic correlations of dimorphic and monomorphic traits in each species. We found two contrasting patterns; F. auricularia exhibited low intrasexual genetic correlations for the dimorphic trait, suggesting that the ITC is moving towards a resolution. Meanwhile, R. echinopus exhibited high and significant intrasexual genetic correlations for most traits, suggesting that morphs in the bulb mite may be limited in evolving to their optima. This also shows that intrasexual dimorphisms can evolve despite strong genetic constraints, contrary to current predictions. We discuss the implications of this genetic constraint and emphasize the potential importance of ITC for our understanding of intrasexual dimorphisms.

No abstract