Oceanographic drivers and mistiming processes shape breeding success in a seabird

Area of Science:

• Marine ecology
• Avian reproduction
• Oceanography

Background:

• Seabird reproductive success is linked to marine food web dynamics.
• Understanding seasonal marine productivity is key to identifying drivers of seabird breeding performance.
• The storm petrel (Hydrobates pelagicus) is a key indicator species for marine ecosystem health.

Purpose of the Study:

• To investigate the environmental and biological factors influencing the reproductive phenology and performance of the storm petrel in the Western Mediterranean.
• To identify the optimal time-window for storm petrel reproduction based on oceanographic drivers.
• To establish a framework for assessing the impact of changing marine productivity on seabird populations.

Main Methods:

• Analysis of environmental data (light, nutrients) and biological data (plankton, fish larvae abundance).
• Correlation of these factors with storm petrel reproductive timing (phenology) and success.
• Statistical analysis accounting for individual factors like age and experience.

Main Results:

• Late winter/early spring stratification enhances marine productivity, creating peaks in phytoplankton, zooplankton, and ichthyoplankton.
• Storm petrel egg production and chick rearing coincide with these food availability pulses.
• Reproduction delayed relative to stratification onset led to hatching and breeding failure, even when controlling for individual factors.

Conclusions:

• Oceanographic drivers create a critical time-window for storm petrel reproduction in the Western Mediterranean.
• Phenological adjustment to seasonal food pulses is crucial for seabird fitness.
• This study provides a framework for evaluating how environmental changes impact seabird reproductive performance.