Do avian species survive better on islands?

Area of Science:

• Ecology
• Evolutionary Biology
• Ornithology

Background:

• Island species often display unique traits compared to mainland counterparts.
• Factors like milder climates and reduced predation on islands influence life-history traits.
• The impact of island living on adult survival, a key factor in reproduction, remains under-explored.

Purpose of the Study:

• To systematically test the hypothesis that island species have higher adult survival rates.
• To investigate the influence of island environments on adult annual apparent survival.
• To determine if the 'island syndrome' extends to adult survival.

Main Methods:

• Compiled data on adult annual apparent survival for island and mainland bird species globally.
• Included 697 year-round resident bird species from both island and mainland populations.
• Controlled for known survival predictors such as body size, clutch size, and breeding system.

Main Results:

• Island bird species demonstrated significantly higher apparent survival rates than mainland species.
• This pattern was consistent across both the Northern and Southern Hemispheres.
• Higher survival rates on islands were observed at all latitudes studied.

Conclusions:

• Island environments appear to confer a survival advantage to adult birds.
• The findings extend the known 'island syndrome' to include enhanced adult survival.
• Ecological factors on islands play a crucial role in influencing avian survival rates.