Evidence for latitude-driven changes in diel rhythms in a wide-ranging seabird

Area of Science:

• Animal behavior
• Chronobiology
• Ecology

Background:

• Diel rhythms, synchronized to light-dark cycles, are common in animals.
• Reduced light cues can lead to weakened or reorganized activity patterns.
• This may allow for more flexible behavioral expression in animals.

Purpose of the Study:

• To investigate variations in diel activity patterns within black-legged kittiwakes across a latitudinal gradient.
• To determine how changing photic environments influence the temporal organization of animal activity.
• To assess the relationship between light-dark cycles and kittiwake activity patterns.

Main Methods:

• Analysis of activity data from over 900 free-ranging black-legged kittiwakes.
• Studying colonies across a wide latitudinal range (40-81°N).
• Correlating activity patterns with environmental factors like sun elevation and light-dark cycles.

Main Results:

• Significant population-level variation in diel activity patterns was observed.
• Lower latitude colonies showed clear 24-hour rhythms with dawn/dusk peaks.
• Higher latitude colonies displayed variable, non-diel rhythms with flattened activity patterns.
• Activity patterns strongly correlated with sun elevation, indicating alignment with the light-dark cycle.

Conclusions:

• The study reveals substantial within-species variation in rhythmicity across latitudes.
• Changes in the photic environment reshape temporal activity organization.
• Black-legged kittiwakes demonstrate adaptability in their diel rhythms based on latitudinal light conditions.