Behavioral Response of American Coots (Fulica americana) to Water Hyacinth (Eichhornia crassipes) in Lake Chapala, Mexico

Abstract

American Coot (Fulica americana) behavior was observed and Water Hyacinth (Eichhornia crassipes) cover measured at Lake Chapala, Mexico, to determine whether site selection, habitat use, behavior within habitat types and selection of habitats for foraging were affected by the invasive aquatic plant. Water Hyacinth significantly affected habitat choice within selected sites but not site selection by coots. Coots spent less time in shallow water and more time in Water Hyacinth as site-level hyacinth cover increased. Water Hyacinth did not restrict coot movement and birds foraged significantly more in patch Water Hyacinth (28.7 ± 2.3% of total time) than in open water (9.8 ± 0.9%). Moreover, coots spent less time foraging in shallow water and more time foraging in hyacinths as cover increased. Coots used Water Hyacinth opportunistically and may have preferred it over other available habitat types. The positive relationships between Water Hyacinth and coots were likely attributed to the introduction of forage and refuge opportunities that were unavailable in Lake Chapala prior to Water Hyacinth invasion. Results suggest that efforts to control Water Hyacinth may indirectly affect the American Coot population.