In 2004 I was elected as the inaugural holder of the Luc Hoffmann Chair in Field Ornithology and appointed Director of the Edward Grey Institute, a research institute based within the Department of Zoology.
I have been Head of Department since October 2016. I am also the Senior User Representative for Life and Mind Building.
I have broad interests in evolution, ecology and behaviour, with a particular focus on understanding the causes and consequences of individual-level variation. My empirical work often uses wild bird populations as a model, particularly exploiting insights drawn from long-term population studies such as that of the great tit in Wytham Woods. My research group typically consists of several postdocs and associated fellows, and 5-6 graduate students. Current research themes include: (1) Social ecology of wild bird populations; (2) Adaptation and constraint in phenotypic plasticity; (3) Ecology and epidemiology of avian malaria; (4) Ecological genetics of life-history characters. We use a combination of field observations and experiments, quantitative and molecular genetic analysis, to understand these problems.
In the last decade our work has been funded by major grants from BBSRC, NERC and the ERC; the latter project ("Evolutionary Social Ecology") developed a new system for collecting very large-scale data on movements and association rates for thousands of individually-marked birds using a grid of automated detectors, and for understanding the determinants and effects of social structure in populations. My most recent NERC grants address (i) the effect of spatial, temporal and developmental constraints on adaptive plasticity, using phenological matching in the tri-trophic oak-winter moth-great tit system, and (ii) testing ecological effects on the diffusion of information in natural populations., while my most recent BBSRC grant tested mechanisms of social learning in wild birds.
Publications
IT TAKES TWO: HERITABLE MALE EFFECTS ON REPRODUCTIVE TIMING BUT NOT CLUTCH SIZE IN A WILD BIRD POPULATION
2020
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Journal article
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Evolution
Social learning of acoustic anti-predator cues occurs between wild bird species
2020
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Journal article
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Proceedings of the Royal Society B: Biological Sciences
Testing the effect of quantitative genetic inheritance in structured models on projections of population dynamics
2019
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Journal article
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OIKOS
Information use in foraging flocks of songbirds - no evidence for social transmission of patch quality
2019
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Journal article
ABSTRACT Animals use behavioural cues from others to make decisions in a variety of contexts. There is growing evidence, from a range of taxa, that information about the locations of food patches can spread through a population via social connections. However, it is not known whether information about the quality of potential food sources transmits similarly. We studied foraging behaviour in a population of wild songbirds with known social associations, and tested whether flock members use social information about the profitability of patches to inform their foraging decisions. We provided artificial patches (ephemeral bird feeders) that appeared identical but were either profitable (contained food) or unprofitable (contained no food). If information about patch profitability spreads via social associations, we predicted that empty feeders would only be sampled by individuals that are less connected to each other than expected by chance. In contrast, we found that individuals recorded at empty feeders were more closely associated with each other than predicted by a null model simulating random arrival of individuals, mirroring pattern of increased connectedness among individuals recorded at full feeders. We then simulated arrival under network-based diffusion of information, and demonstrate that the observed pattern at both full and empty feeders matches predictions derived from this post-hoc model. Our results suggest that foraging songbirds only use social cues about the location of potential food sources, but not their profitability. These findings agree with the hypothesis that individuals balance the relative economic costs of using different information, where the costs of personally sampling a patch upon arrival is low relative to the cost of searching for patches. This study extends previous work on information spread through avian social networks, by suggesting important links between how animals use information at different stages of the acquisition process and the emerging population-level patterns of patch use.
Cue identification in phenology: A case study of the predictive performance of current statistical tools.
2019
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Journal article
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The Journal of animal ecology
Changes in the timing of life-history events (phenology) are a widespread consequence of climate change. Predicting population resilience requires knowledge of how phenology is likely to change over time, which can be gained by identifying the specific environmental cues that drive phenological events. Cue identification is often achieved with statistical testing of candidate cues. As the number of methods used to generate predictions increases, assessing the predictive accuracy of different approaches has become necessary. This study aims to (a) provide an empirical illustration of the predictive ability of five commonly applied statistical methods for cue identification (absolute and relative sliding time window analyses, penalized signal regression, climate sensitivity profiles and a growing degree-day model) and (b) discuss approaches for implementing cue identification methods in different systems. Using a dataset of mean clutch initiation timing in wild great tits (Parus major), we explored how the days of the year identified as most important, and the aggregate statistic identified as a cue, differed between statistical methods and with respect to the time span of data used. Each method's predictive capacity was tested using cross-validation and assessed for robustness to varying sample size. We show that the identified critical time window of cue sensitivity was consistent across four of the five methods. The accuracy and precision of predictions differed by method with penalized signal regression resulting in the most accurate and most precise predictions in our case. Accuracy was maximal for near-future predictions and showed a relationship with time. The difference between predictions and observations systematically shifted across the study from preceding observations to lagging. This temporal trend in prediction error suggests that the current statistical tools either fail to capture a key component of the cue-phenology relationship, or the relationship itself is changing through time in our system. These two influences need to be teased apart if we are to generate realistic predictions of phenological change. We recommend future phenological studies to challenge the idea of a static cue-phenology relationship and should cross-validate results across multiple time periods.
Animals, Cues, Seasons, Climate Change
Wild songbirds exhibit consistent individual differences in inter-specific social behaviour
2019
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Journal article
A BSTRACT <jats:list list-type="order"><jats:list-item> Natural populations and communities consist of individuals that differ in their phenotypes. There is increasing evidence in community ecology that consistent intraspecific variation in behaviour changes the outcome of ecological interactions. <jats:list-item> Differences in intra- and inter-specific interactions are expected to play a major role in determining patterns of species coexistence and community structure. However, the question of whether individuals vary in their propensity to associate with heterospecifics has been neglected. <jats:list-item> We used social network analysis to characterise pattern of heterospecific associations in wild mixed-species flocks of songbirds, and assessed whether individuals adopt consistent social strategies in their broader, heterospecific, social environment. We quantified heterospecific foraging associations using data from a large automatically monitored PIT-tagged population of birds, involving more than 300 000 observations of flock membership, collected over three winters, for two tit species (Paridae), blue tits, Cyanistes caeruleus , and great tits, Parus major . <jats:list-item> We assessed individual consistency in interspecific social preferences over both short-term (week-to-week) and longer-term (year-to-year) timescales for a total of 4610 individuals, and found that blue tits and great tits exhibited marked and consistent intraspecific differences in heterospecific social phenotypes in terms of both absolute and relative number of associates. Further, we found that these consistent differences were significantly greater than expected from spatial and temporal differences in population densities. <jats:list-item> Heterospecific associations represent a major component of the social environment for many species, and our results show that individuals vary consistently in their social decisions with respect to heterospecifics. These findings provide support for the notion that intraspecific trait variation contributes to patterns at community and ecosystem levels.
Adaptive responses of animals to climate change are most likely insufficient.
2019
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Journal article
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Nature communications
Biological responses to climate change have been widely documented across taxa and regions, but it remains unclear whether species are maintaining a good match between phenotype and environment, i.e. whether observed trait changes are adaptive. Here we reviewed 10,090 abstracts and extracted data from 71 studies reported in 58 relevant publications, to assess quantitatively whether phenotypic trait changes associated with climate change are adaptive in animals. A meta-analysis focussing on birds, the taxon best represented in our dataset, suggests that global warming has not systematically affected morphological traits, but has advanced phenological traits. We demonstrate that these advances are adaptive for some species, but imperfect as evidenced by the observed consistent selection for earlier timing. Application of a theoretical model indicates that the evolutionary load imposed by incomplete adaptive responses to ongoing climate change may already be threatening the persistence of species.
Animals, Birds, Acclimatization, Phenotype, Time Factors, Selection, Genetic, Climate Change
