Sibling competition and parental control: Patterns of begging in parrots

Begging and food allocation patterns are the outcome of complex and repeated interactions between parents and young. In most systems studied, food allocation is regulated by begging and scramble competition. In contrast, little is understood about how nestling solicitation behaviours will evolve in systems where parents engage in complex patterns of food allocation. Parrots appear to be an excellent group in which to examine the shifting balance between sibling competition and parental control. Studies to date have shown that levels of sibling competition within parrot broods are low, possibly in response to parental control over food distribution. I assess what is known about the function of nestling begging in parrots and evaluate why begging signals appear to function differently in this group.

Age and Offending: Characteristics and Criminological Factors

Adolescence is popularly understood as a transitional phase of turbulence and extremes. It is also often associated with 'trouble'. Criminal justice statistics, however, reveal that youth criminality remains a relatively rare phenomenon, less than one percent of the total adolescent population in any given year. This exceptional book is based upon a major Australian research programme to consider the key social factors impacting upon the lives of young people. A sample of 1,300 young people was divided into three major subgroups: a 'control' group, drawn from state secondary schools and closely approximating the general population; a chronically marginalized cohort representing a 'vulnerable group', and a group of offenders, most of whom were incarcerated at the time of the research.