Practice question

Cattle egrets often forage near grazing cattle because the mammals’ movement through grass flushes insects and other small animals into view. The bird gains a higher capture rate or reduced search effort, while the cattle are generally assumed to experience neither benefit nor harm. This asymmetrical (+, 0) effect is commensalism. The egret is not consuming tissue from the cattle, so the relationship is not parasitism; its predation is directed at the disturbed insects. Mutualism would require evidence that cattle benefit, perhaps through removal of ectoparasites, but the classic example specifies prey flushed from vegetation rather than parasites taken from the body. “Predation” correctly describes the egret–insect interaction, not the cattle–egret association being classified. The neutrality assumption should be tested rather than presumed because birds could occasionally remove pests or distract livestock. Ecological labels depend on the focal pair and net fitness consequences: one event can simultaneously contain commensalism between cattle and egret and predation between egret and insect.