Modelling the progression of bird migration with conditional autoregressive models applied to ringing data.

Area of Science:

• Ornithology
• Ecology
• Conservation Biology

Background:

• Bird migration is a critical life-history trait influenced by selective pressures.
• Ring recovery databases are essential for studying migration patterns and changes over time.
• The Barn Swallow (Hirundo rustica) is a widely studied migratory bird species.

Purpose of the Study:

• To model the progression of Barn Swallow migration across Europe using historical ring recovery data.
• To investigate changes in migration timing over three distinct time periods (1908-2008).
• To assess regional variations in migration phenology.

Main Methods:

• Utilized a century of Barn Swallow (Hirundo rustica) ring recovery data from Europe (1908-2008).
• Employed binomial conditional autoregressive (CAR) mixed models to analyze migration timing and progression.
• Expanded analyses from the British Isles to western Europe and north Africa.

Main Results:

• Generated migration progression maps accurately reflecting local and regional patterns.
• Found no significant advancement in spring migration across Europe.
• Observed a significant advancement in autumn migration timing specifically in southern Europe.

Conclusions:

• The developed modeling approach offers a robust method for analyzing migration phenology using ring recovery data.
• Migration timing analysis revealed distinct regional shifts, particularly an earlier autumn migration in southern Europe.
• Findings contribute to understanding long-term impacts on migratory bird populations and inform conservation strategies.