Mallard Hybridization With Domesticated Lineages Alters Spring Migration Behavior and Timing.

Area of Science:

• Ecology and evolutionary biology
• Conservation genetics
• Wildlife behavior

Background:

• Introgressive hybridization is increasing due to human activities.
• Domestic-wild hybridization can negatively impact individual fitness and population demographics.
• Hybridization between game-farm and wild mallards is altering genetic structure in North American flyways.

Purpose of the Study:

• To investigate differences in spring migratory behavior of mallards with varying levels of game-farm ancestry.
• To assess the impact of genetic introgression on mallard migration patterns and potential fitness consequences.

Main Methods:

• GPS tracking of 296 mallards captured in Tennessee and Arkansas.
• Quantification of game-farm ancestry using genetic analysis.
• Analysis of migratory departure/arrival times, distances, and settlement locations.

Main Results:

• Mallards with higher game-farm ancestry exhibited later spring departure and arrival times.
• Increased game-farm genetics correlated with shorter migration distances and lower latitude residency.
• Every 10% increase in game-farm genetics led to significant shifts in migration timing and distance.

Conclusions:

• Genetic introgression from game-farm mallards significantly influences migratory behavior.
• Altered migratory patterns may reduce fitness and contribute to wild mallard population declines.
• Understanding domestic hybridization effects is crucial for other species conservation.