—Rules of food allocation between nestlings of the black-billed magpie Pica pica, a species showing brood reduction. Aims: The existence of a size hierarchy of nestlings in a brood facilitates a secondary readjustment of brood size to resource availability, through the death of the smaller chicks when food is scarce. A mechanism to facilitate brood reduction would be for parents preferentially ...

The ultimate goal of nesting is the production of young and therefore predation and brood parasitism may constrain reproductive success. Breeding azurewinged magpies (Cyanopica cyanus) were exposed to mounts of an sparrowhawk (Accipiter nisus) (i.e. an avian predator on adult and fledged chicks), a female great spotted cuckoo (Clamator glandarius) (i.e. a brood parasite that also preys on eggs ...

Several experimental results support the existence of costs associated with exaggerated begging behaviour, which are assumed by some theoretical models of honest signalling in parent-offspring communication. However, to understand how honest begging behaviour is evolutionarily maintained in nature, the long-term cost-benefit output associated with exaggerated signals should also be estimated. A...

In the coming decades, world agricultural systems will face serious transitions. Population growth, income and lifestyle changes will lead to considerable increases in food demand. Moreover, a rising demand for renewable energy and biodiversity protection may restrict the area available for food production. On the other hand, global climate change will affect production conditions, for better o...

1. Evolutionary theory predicts that individuals, in order to increase their relative fitness, can evolve behaviours that are detrimental for the group or population. This mismatch is particularly visible in social organisms. Despite its potential to affect the population dynamics of social animals, this principle has not yet been applied to real-life conservation. 2. Social group structure has...

Members of the thrush family (Turdidae) are renowned for a quite melodious but nevertheless complex mode of singing. Such holds true also for the Oriental Magpie Robin (Copsychus saularis) that settles in some tropical regions of Asia. We have studied the territorial singing of this species in the area of Biratnagar (Nepal), and present a list of first results here. Analysis of singing episodes...

Between 1997 and 1998 the breeding density, nest sites, clutch size and egg dimensions of the magpie (Pica pica) was investigated in a 7 km2 area in the Krapina river valley. We recorded a high breeding density of 4.79 pairs/km2 (during both years). The nests were situated at a height of 1–16 m above ground (mean = 6.74 m). Magpie nests were found in at least 9 species of bushes and trees. We r...

Hosts can counteract parasites through defences based on resistance and/or tolerance. The mechanistic basis of tolerance, which involve defensive mechanisms minimizing parasite damage after a successful parasitic attack, remains poorly explored in the study of cuckoo-host interactions. Here, we experimentally explore the possibility that the risk of great spotted cuckoo Clamator glandarius para...

Brood parasites are expected to lay only one egg per parasitized nest, as the existence of several parasitic nestlings in a brood increases competition and can lead starvation some them. However, multiparasitism (laying two or more eggs by females single host nest) is surprisingly frequent. Here, we study different same female (repeated parasitism) great spotted cuckoo Clamator glandarius, non-...