Haddou, Y. | bioRxiv Science

bioRxiv2022

No evidence that urbanisation encourages wild red foxes (Vulpes vulpes) to exploit unfamiliar food-related objects when first discovered

Urbanisation is the fastest form of landscape transformation on the planet, but researchers understanding of the relationships between urbanisation and animal adaptability is still in its infancy. In terms of foraging, bold and innovative behaviours are proposed to help urban animals access, utilise, and exploit novel anthropogenic food sources. Red foxes (Vulpes vulpes) are one of the best known and widespread urban-dwelling species. However, despite frequent stories, images, and videos portraying them as "pests" due to their exploitation of food-related objects (e.g., raiding the contents of outdoor bins), it is unknown whether they are bolder and more innovative in terms of their likelihood of exploiting these resources compared to rural populations. In the current study, we gave novel food-related objects to foxes from 104 locations (one object per location) across a large urban-rural gradient. To access the food, foxes had to use behaviours necessary for exploiting many food-related objects in the real world (e.g., biting, pushing, pulling, or lifting human-made materials). Despite all foxes acknowledging the objects, foxes from 31 locations touched them, while foxes from 12 locations gained access to the food inside. A principal component analysis of urban and other landscape variables (e.g., road, greenspace, and human population density) revealed that urbanisation was significantly and positively related to the likelihood of foxes touching, but not exploiting, the objects. Thus, while urban foxes may be bolder than rural populations in terms of their willingness to physically touch novel food-related objects, our findings are inconsistent with the notion that they are more innovative and pose a general nuisance to people by exploiting these anthropogenic resources. HighlightsO_LIThe impact of urbanisation on animal adaptability remains unclear C_LIO_LIBold and innovative behaviour may help some urban species thrive C_LIO_LIWe studied wild red foxes responses to novel food-related objects C_LIO_LIUrban foxes were bolder, but not more innovative, than rural foxes C_LIO_LIUrbanisation may favour bolder, not more innovative, fox behaviour C_LI

animal behavior and cognition↗

bioRxiv2021

A global meta-analysis reveals more variable life histories in urban birds compared to their non-urban neighbours

Cities pose a major ecological challenge for wildlife worldwide. Phenotypic variation, which can result from underlying genetic variation or plasticity, is an important metric to understand eco-evolutionary responses to environmental change. Recent work suggests that urban populations might have higher levels of phenotypic variation than non-urban counterparts. This prediction, however, has never been tested across species nor over a broad geographical range. Here, we conduct a meta-analysis of the avian literature to compare urban versus non-urban means and variation in phenology (i.e., lay date) and reproductive effort (i.e., clutch size, number of fledglings). First, we show that urban populations reproduce earlier and have smaller broods than non-urban conspecifics. Second, we show that urban populations have higher phenotypic variation in laying date than non-urban populations. This result arises from differences between populations within breeding seasons, conceivably due to higher landscape heterogeneity in urban habitats. These findings reveal a novel effect of urbanisation on animal life-histories with potential implications for species adaptation to urban environments (which will require further investigation). Higher variation in phenology in birds subjected to urban disturbance could result from plastic responses to a heterogeneous environment, or from higher genetic variation in phenology, possibly linked to higher evolutionary potential.

evolutionary biology↗