Planet of Birds

Kestrel (Falco tinnunculus) Science Article 1 abstract To investigate time, energy, and temperature constraints on hatching asynchrony in Eurasian Kestrels (Falco tinnunculus), we observed females during the laying period and quantified the time spent hunting to see whether this might limir time spent incubating. We predicted that females would hunt more in years when the […]

Kestrel (Falco tinnunculus) Science Article 9 abstract We studied reproductive parameters, nest-site characteristics and breeding success of theEurasian Kestrel (Falco tinnunculus canariensis) on Tenerife Island, Canary Archipelago.Kestrels typically breed in cliffs cavities (79.4%), and were present in all habitatsfrom sea level to 2,400 m, except in shrubby heaths (rich in Myrica faya and Ericaarborea) and […]

Kestrel (Falco tinnunculus) Science Article 6 abstract The hunting flight of the kestrel (Falco tinnunculus) consists of short bouts of flight at wind speed against the wind with the eyes in a fixed position relative to the ground, and of short flights from one such position to the next. High speed films taken with a […]

Kestrel (Falco tinnunculus) Science Article 10 abstract Sex differences in testosterone levels and sex-biased sensitivity to testosterone are the basis of some ideas postulated to account for sex-linked environmental vulnerability during early life. However, sex variation in circulating testosterone levels has been scarcely explored and never manipulated at post-natal stages of birds in the wild. […]

Kestrel (Falco tinnunculus) Science Article 2 abstract When resources are limited, parents should decide the optimal number, size, and sex of progeny, and offspring should decide the optimal allocation of resources to different costly functions, such as growth and immunity. We manipulated clutch sizes of Eurasian kestrels by one egg to estimate possible cumulative effects […]

Kestrel (Falco tinnunculus) Science Article 3 abstract Hatching asynchrony in altricial birds may result in a competitive disadvantage for the youngest nestlings compared to older siblings. We studied the effects of a size hierarchy on the growth rate of Eurasian kestrels Falco tinnunculus chicks in nests with and without access to supplemented food in western […]

Kestrel (Falco tinnunculus) Science Article 11 abstract Mate-guarding and frequent within-pair copulations are the two main paternityguards of male birds. Some species of birds of prey depend on large foraging areas due tothe availability and dispersion of their food, and males supply their females with food frommating until early chick rearing. Furthermore, birds of prey […]

Kestrel (Falco tinnunculus) Science Article 4 abstract Resource allocation from parents to their offspring can be modulated by inter-sexual size dimorphism. High dimorphism promotes differential costs in rearing male and female offspring and unequal competitive ability among siblings. We examined whether any of these types of biases occur in Eurasian kestrels, Falco tinnunculus, in which […]

Kestrel (Falco tinnunculus) Science Article 5 abstract 1) Offspring sex ratio may be an unpredictable component of life history that might select for behavioural plasticity in parental care. If the parents do not have such plasticity and the two sexes of offspring differ in size, individuals in a brood or litter biased towards the larger […]

Kestrel (Falco tinnunculus) Science Article 8 abstract Ringing recoveries of European Kestrels from north-western Europe have shown that a very low proportion of this population is migratory, and that even large-distance movements can be attributed mainly to dispersal movements of young birds. Several studies have shown the importance of food availability on dispersal rates in […]