title: Environmental variation at the onset of independent foraging affects full-grown body mass in the red fox.
abstract: The period following the withdrawal of parental care has been highlighted as a key developmental period for juveniles. One reason for this is that juveniles cannot forage as competently as adults, potentially placing them at greater risk from environmentally-induced changes in food availability. However, no study has examined this topic. Using a long-term dataset on red foxes (Vulpes vulpes), we examined (i) dietary changes that occurred in the one-month period following the attainment of nutritional independence, (ii) diet composition in relation to climatic variation, and (iii) the effect of climatic variation on subsequent full-grown mass. Diet at nutritional independence contained increased quantities of easy-to-catch food items (earthworms and insects) when compared with pre-independence. Interannual variation in the volume of rainfall at nutritional independence was positively correlated to the proportion of earthworms in cub diet. Pre-independence cub mass and rainfall immediately following nutritional independence explained a significant proportion of variance in full-grown mass, with environmental variation affecting full-grown mass of the entire cohorts. Thus, weather-mediated availability of easy-to-catch food items at a key developmental stage has lifelong implications for the development of juvenile foxes by affecting full-grown mass, which in turn appears to be an important component of individual reproductive potential.
authors.affiliation: School of Biological Sciences, University of Bristol, Woodland Road, Bristol BS8 1UG, UK. carl.soulsbury@bristol.ac.uk
authors.forename: Carl D
authors.initials: CD
authors.lastname: Soulsbury
authors.forename: Graziella
authors.initials: G
authors.lastname: Iossa
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Baker
authors.forename: Stephen
authors.initials: S
authors.lastname: Harris
mesh_terms: D000818:Animals; D049628:Body Size; D015331:Cohort Studies; D004032:Diet; D004777:Environment; D005247:Feeding Behavior; D005260:Female; D005589:Foxes / Q000254:growth & development*; D008297:Male; D018709:Statistics, Nonparametric