Agricultural land use and human presence around breeding sites increase stress-hormone levels and decrease body mass...

Area of Science:

• Wildlife ecology
• Animal physiology
• Conservation biology

Background:

• Human activities impact animal life history and physiology.
• Glucocorticoids, like corticosterone, are stress hormones with acute benefits but chronic detriments.
• Long-term elevation of glucocorticoids can impair growth and immune function.

Purpose of the Study:

• To investigate the effects of landscape and human activities on barn owl nestlings.
• To assess physiological stress responses (corticosterone levels) and fitness parameters (growth, breeding performance).

Main Methods:

• Studied nestling barn owls (Tyto alba) in relation to surrounding landscapes and human activities.
• Measured baseline and stress-induced corticosterone levels.
• Assessed nestling body mass and overall breeding performance.

Main Results:

• Intensive agriculture correlated with higher corticosterone and lower body mass in nestlings.
• Frequent human disturbance led to elevated corticosterone and reduced body mass.
• Structurally diverse landscapes were associated with improved breeding performance.

Conclusions:

• Anthropogenic disturbance primarily affects offspring quality (physiological stress, body mass) rather than quantity.
• Agricultural practices impact both offspring quality and quantity (life history traits).
• Landscape structure plays a role in supporting successful barn owl reproduction.