Host space, not energy or symbiont size, constrains feather mite abundance across passerine bird species.

Comprehending symbiont abundance among host species is a major ecological endeavour, and the metabolic theory of ecology has been proposed to understand what constrains symbiont populations. We parameterized metabolic theory equations to investigate how bird species' body size and the body size of their feather mites relate to mite abundance according to four potential energy (uropygial gland size) and space constraints (wing area, total length of barbs and number of feather barbs). Predictions were compared with the empirical scaling of feather mite abundance across 106 passerine bird species (26,604 individual birds sampled), using phylogenetic modelling and quantile regression.

Rapid behavioural response of urban birds to COVID-19 lockdown.

Biodiversity is threatened by the growth of urban areas. However, it is still poorly understood how animals can cope with and adapt to these rapid and dramatic transformations of natural environments. The COVID-19 pandemic provides us with a unique opportunity to unveil the mechanisms involved in this process.

Egg recognition: The importance of quantifying multiple repeatable features as visual identity signals.

Brood parasitized and/or colonial birds use egg features as visual identity signals, which allow parents to recognize their own eggs and avoid paying fitness costs of misdirecting their care to others' offspring. However, the mechanisms of egg recognition and discrimination are poorly understood. Most studies have put their focus on individual abilities to carry out these behavioural tasks, while less attention has been paid to the egg and how its signals may evolve to enhance its identification.

Complex phenological changes and their consequences in the breeding success of a migratory bird, the white stork Ciconia ciconia.

1. The timing of bird migration has shifted in response to climate change. However, few studies have linked the potential consequences of any phenological shift on individual fitness and even fewer have disentangled the role of plasticity and microevolution in the observed shifts.

Challenging claims in the study of migratory birds and climate change.

Recent shifts in phenology in response to climate change are well established but often poorly understood. Many animals integrate climate change across a spatially and temporally dispersed annual life cycle, and effects are modulated by ecological interactions, evolutionary change and endogenous control mechanisms. Here we assess and discuss key statements emerging from the rapidly developing study of changing spring phenology in migratory birds.

Determining the environmental factors underlying the spatial variability of insect appearance phenology for the honey bee, Apis mellifera, and the small white, Pieris rapae.

The spatial patterns of the variability of the appearance dates of the honey bee Apis mellifera L. (Hymenoptera: Apidea) and the small white Pieris rapae (L.) (Lepidoptera: Pieridae) were investigated in Spain.

Phenology and climate change: a long-term study in a Mediterranean locality.

It is well documented that plant and animal phenology is changing in response to recent climate warming in the Palaearctic. However, few long-term data sets are currently available in the Mediterranean basin. The present study reports long-term temporal trends of several phenophases of 45 plants, 4 insects and 6 migratory insectivorous birds.