Chemical defences against predators are widespread in the animal kingdom although have been seldom reported in birds. Here, we investigate the possibility that the orange liquid that nestlings of an insectivorous bird, the Eurasian roller (Coracias garrulus), expel when scared at their nests acts as a chemical defence against predators. We studied the diet of nestling rollers and vomit origin, ...

Parental care plays a key role in ontogeny, life-history trade-offs, sexual selection and intra-familial conflict. Studies focusing on understanding causes and consequences of variation in parental effort need to quantify parental behaviour accurately. The applied methods are, however, diverse even for a given species and type of parental effort, and rarely validated for accuracy. Here we focus...

Parental body mass changes during the nesting period were analysed for Thekla Larks, Galerida theklae, and Lesser Short-toed Larks, Calandrella rufescens. Body mass of female Thekla Larks declines from the start of incubation until the chicks fledge; laying date, interpreted as the number of renesting attempts, also has a negative effect. Body mass of female Lesser Short-toed Larks was not rela...

Avian eggs contain considerable amounts of maternal yolk androgens, which have been shown to beneficially influence the physiology and behaviour of the chick. As androgens may suppress immune functions, they may also entail costs for the chick. This is particularly relevant for colonial species, such as the black-headed gull (Larus ridibundus), in which the aggregation of large numbers of birds...

Previous studies demonstrated that amongst food-storing passerine birds the hippocampal region (dorso-medial cortex) is enlarged relative to the rest of the telencephalon. It has been hypothesised that this hippocampal specialisation is related to the spatial memory requirements of retrieving large numbers of stored items. Here we compare the development of the hippocampus in a food-storing and...

The immune system is one of the most important adaptations that has evolved to protect animals from a wide range of pathogens they encounter from early life onwards. During the early developmental period this is particularly true for the innate immunity, as other components of the immune system are, as yet, poorly developed. But innate immunity may not only be crucial for early life survival, b...

One of the main populations of the Florida scrub-jay (Aphelocoma coerulescens), a federally threatened species, occurs on Ocala National Forest, Florida. We determined the nest daily survival rate (DSR) of 474 nests of Florida scrub-jays in stands subject to sand pine reforestation management after timber harvesting or wildfire on Ocala National Forest. We used the information-theoretic approac...

Because predation is the main cause of avian nest failure, selection should favor strategies that reduce the probability of nest predation. We describe apparent Batesian mimicry in the morphology and behavior of a Laniocera hypopyrra nestling. On hatching, the nestling had a distinctive bright orange color and modified feathers all over its body, and 6 days after hatching, it started to move it...