Kevin is studying predator-prey interactions. One day he notices a spider eating a cricket caught in its web. Later that day, a bird eats the spider. How many consumers has Kevin observed directly in this scenario?

Kevin has observed 2 consumers, the primary consumer, the spider, and the secondary consumer is the bird.

Explanation:

The producer in this scenario is the cricket, and the spider eats first, that's why its called the "primary" consumer.