All dictionaries I have checked list the term wildlife as an uncountable noun. But there are plenty of examples that treat wildlife as a plural.
I've found it difficult to wrap my head around this word: Is this an uncountable noun as the dictionaries say or can this be sometimes treated as a collective mass noun that can represent a plural?
Wildlife is a mass noun – broadly, it encompasses a group that shares the homogenous characteristics of moving and being alive and wild. As such, it is uncountable, i.e. it doesn’t have a plural form; it can’t be qualified by a number, and its quantifier is “much”, not “many.”
Does it take a plural verb?
Consider:
1 “The team is playing well.”
2 “The team are playing well.”
In British English, both are correct and have different nuances:
In 1, we have “The team, considered as a single unit, is playing well.” -> It is playing well.
In 2, we have “The team, considered as 11 individual players, are playing well”, i.e. the players of the team are playing well.” -> They are playing well.
Now:
3 “The wildlife in the area is suffering” -> this is the preferred version as "wildlife" (unlike "team") is uncountable.
4 “The wildlife in the area are suffering” -> this is often incorrectly used by speakers of British English based upon the "team" example above. However, it does not sound "awful" and would normally be overlooked.
In 3, “The wildlife” is considered as a single whole unit, and is suffering” -> It is suffering
In 4, “The wildlife” is considered as individual animals/birds/insects, etc. -> They are suffering.