“大批出没”可以翻译为“appear in large numbers” 或者 “swarm in large quantities” ，具体使用可根据语境稍作调整：
* “appear in large numbers” 更侧重于描述大量事物或人同时出现、存在的场景，比较通用。例如：Wild animals often appear in large numbers in this reserve.（在这个保护区里，野生动物经常大批出没 。）
* “swarm in large quantities” 强调像蜂群一样大量聚集、涌动，更生动形象地描绘出大批快速移动、聚集的状态。例如：Insects swarmed in large quantities around the light source.（昆虫大批出没，在光源周围聚集 。）