Five species of warblers studied by Mac Arthur is an example of:

The correct answer is Option (2) → Resource partitioning

Option (1) Competitive release — Incorrect. Competitive release is the spread of a species when its competitor is removed.

Option (2) Resource partitioning — Correct. MacArthur found that five closely related species of warblers lived on the same tree without competing. They fed in different parts of the tree and in different ways; this is resource partitioning.

Option (3) Competitive exclusion — Incorrect. Competitive exclusion (Gause’s principle) says that two closely related species competing for the same resources cannot co-exist; the inferior one is eliminated. Here all five warbler species co-existed, so there was no exclusion.

Option (4) Co-extinction — Incorrect. Co-extinction is the loss of a species with its host.

NCERT Extract:
Population Interactions – “… If two species compete for the same resource, they could avoid competition by choosing, for instance, different times for feeding or different foraging patterns. MacArthur showed that five closely related species of warblers living on the same tree were able to avoid competition and co-exist due to behavioural differences in their foraging activities.”