During the nonreproductive season, birds show a full spectrum of social organizations from
solitary birds aggressively defending feeding territories to flocking birds amicably sharing …

Here I describe a variety of mutually beneficial interactions between birds that typically are
not genetically related. As viewed here, avian cooperation and reciprocity can take several …

Avian social systems during the breeding season can be classified into three major types:
territorial, cooperative or communal, and colonial. This classification is based on the degree …

(Editors' comments: A variety of bird species have been domesticated, and these represent a
wide range of social behaviour. Natural group sizes range from solitary to large …

The social environment is a critical determinant of fitness and, in many taxa, is shaped by an
individual's behavioral discrimination among social contexts, suggesting that animals can …

An overview of the extensive and frequently controversial literature on communally breeding
birds developed since the early 1960s, when students of evolution began to examine …

In examining the factual evidence on which the concept of population regulation through
territorial behavior is based it was found desirable to differentiate between three critical …

It is only recently that zoological workers and those in comparative psychology have realized
that the group is a major ecological factor in the life of the individual. Sociality is fundamental …

Stacey and Koenig discuss the phenomenon of cooperative breeding among birds, an
unusual kind of social behavior common to only a few hundred species worldwide, in which …

I argue that a net benefit model of aggressive social organization is consonant with
observed variation between territorial and dominance systems. For nectarivores net benefits …