de Knegt, H. J. | Search bioRxiv

bioRxiv2024

Flight performance, activity and behaviour of breeding pied flycatchers in the wild, revealed with accelerometers and machine learning

Flight behaviours have been extensively studied from different angles such as their kinematics, aerodynamics and more general their migration pattern. Nevertheless, much is still unknown about the daily flight activity of birds, in terms of their performance, behaviour and the potential differences between males and females. The recent development of miniaturized accelerometers allows us a glimpse into the daily life of a songbird. Here, we tagged 26 pied flycatchers (Ficedula hypoleuca) with accelerometers and analysed using machine learning approaches their flight performance, activity and behaviour during their chick rearing period. We found that during two hours of foraging chick-rearing pied flycatchers were flying 13.7% of the time. Almost all flights (>99%) were short flights lasting less than 10s. Flight activity changed throughout the day and was highest in the morning and lowest in the early afternoon. Male pied flycatcher had lower wing loading than females, and peak flight accelerations were inversely correlated with wing loading. Despite this, we found no significant differences in flight activity and performance between sexes. This suggests that males possess a higher potential flight performance, which they not fully utilized during foraging flights. Our results thus suggest that male and female pied flycatcher invest equally in parental care, but that this comes at a reduced cost by the male, due to their higher flight performance potential.

animal behavior and cognition↗

bioRxiv2022

Movement of large African savanna herbivores is shaped by intricate interactions between behavioural modes and the spatial-temporal environment

O_LIAnimal movement arises from complex interactions between animals and their heterogeneous environment, making it challenging to capture the movement process in a single analysis. This has lead to a bias towards lower-dimensional representations of the process in such analyses. In order to better understand animal movement, its multiple components should be included and addressed simultaneously. C_LIO_LIWe present an analytic framework that integrates the behavioural, spatial, and temporal components of the movement process and their interactions, and allows for assessing the relative importance of these components. We propose a daily cyclic covariate to represent temporally cyclic movement patterns, for example diel variation in activity, and combine the three components in multi-modal Hidden Markov Models. We compare the statistical fits of models that include or exclude any of the behavioural, spatial and temporal components, and perform variance partitioning on the model that included all components to assess their relative importance to the movement process, both in isolation and in interaction. C_LIO_LIWe apply our framework to a case study on the movements of zebra, wildebeest and eland antelope in a South African reserve. Behavioural modes impacted movement the most, followed by diel rhythms and then the spatial environment (i.e. tree cover and terrain slope). Interactions between the components often explained more of the movement variation than the marginal effect of the spatial environment did on its own. Omitting components from the analysis led either to failure to detect relationships between input and response variables, resulting in overgeneralisations when drawing conclusions about the movement process, or to erroneously detecting spurious relationships, resulting in factually incorrect conclusions. C_LIO_LIOur analytic framework can be used to study animal movement by integrating the different components of the movement process, thereby preventing incomplete or overly generic ecological interpretations. We demonstrate that understanding the drivers of animal movement, and ultimately the ecological phenomena that emerge from it, critically depends on considering the various components of the movement process, and especially the interactions between them. C_LI Data/code for peer review statement: the data and code needed to reproduce the study and results are uploaded as a file with the initial submission.

ecology↗