Following the definitions of both tertiary and consumer it follows that we have third feeder (consumer). An example of this in reality would be something like a hawk. The tertiary consumer is the organism that eats (consumes) the secondary consumer.
The turtle fairy (tertiary) jumping on the three seater sofa wasn’t aware that every time it jumped it attracted a hawk that swept down to grab him.
Like all food chains this one begins with a producer, which in this case is the oak tree, the next organism in the sequence is the caterpillar which eats the oak tree leaves. The caterpillar is the primary consumer which is then eaten by the next organism in the feeding sequence, the treecreeper (small bird), known as the secondary consumer. Finally the treecreeper (small bird) is eaten by the tertiary consumer which in this food chain is the hawk.
Salmon eat insects and flies, humans eat salmon and occasionally bears eat humans.