Development of the Visual System in a Burrow-Nesting Seabird: Leach's Storm Petrel

Area of Science:

• Avian biology
• Neuroscience
• Developmental biology

Background:

• Limited understanding of wild bird vision development.
• Semi-precocial seabird species nesting in dark environments present unique developmental challenges.
• Leach's storm petrel (Oceanodroma leucorhoa) relies on olfaction, raising questions about visual system maturation.

Purpose of the Study:

• Investigate eye growth and retinal ganglion cell topography in Leach's storm petrel chicks.
• Determine the onset of visually guided behaviors in developing chicks.
• Correlate visual development with other sensory systems and overall growth.

Main Methods:

• Analysis of retinal ganglion cell layer maturation through topographic mapping.
• Measurement of eye and telencephalon growth.
• Behavioral experiments assessing optokinetic head response and burrow finding ability.

Main Results:

• Retinal ganglion cell topography matures throughout the provisioning period and potentially post-fledging.
• Olfactory bulbs reach adult size by 7 weeks, while eyes and telencephalon continue growing.
• Chicks in the second week post-hatching exhibit no visually guided behaviors, indicating blindness.

Conclusions:

• Vision in Leach's storm petrel chicks begins functioning around the third week after hatching.
• Visual system development significantly lags behind olfactory system maturation.
• This delayed visual development is likely an adaptation to the dark, burrow-nesting environment.