Do avian cooperative breeders live longer?

Area of Science:

• Avian Ecology
• Evolutionary Biology
• Behavioral Ecology

Background:

• Cooperative breeding is rare in birds but concentrated in certain families, suggesting underlying evolutionary drivers.
• The life-history hypothesis posits that high annual survival and limited breeding opportunities promote cooperative breeding, potentially with smaller clutch sizes.

Purpose of the Study:

• To investigate the relationship between life-history traits and the evolution of cooperative breeding in birds.
• To test whether high annual survival and reduced clutch size are associated with cooperative breeding across a global avian sample.
• To control for confounding factors such as diet, body mass, and sampling effort.

Main Methods:

• Comparative analysis of closely related cooperative and non-cooperative bird species pairs.
• Statistical control for diet, body mass, and sampling effort in longevity analyses.
• Analysis of adult annual survival and clutch size in relation to cooperative breeding.

Main Results:

• No significant association was found between maximum longevity and cooperative breeding in a large sample (81 species pairs).
• Adult annual survival was significantly higher in cooperative breeders compared to non-cooperative breeders in a smaller sample (37 pairs), controlling for body mass.
• No association was detected between clutch size and cooperative breeding across 93 species pairs.

Conclusions:

• High adult annual survival appears to be a facilitating factor in the evolution of cooperative breeding in birds.
• The hypothesized link between cooperative breeding and reduced clutch size was not supported by this study.
• Further research is needed to fully understand the ecological and life-history factors driving cooperative breeding strategies in birds.