In what ways can a druid's Wild Shape be detected?

Question

I'm a relative newcomer to D&D 5th Ed. and am playing a druid fond of Wild Shape. I'd like to know in what ways it can be detected by NPCs (or even fellow PCs). It appears that this is a sort of debated subject, as to how and whether Detect Magic works on it or not.

I read through the question, Detecting Wild Shape with a Mythal, but I've no idea what a Mythal is. In portions of the question and its answers, there seems to be various interpretations of how Detect Magic might work (or not). It seems to me that the ability is a sort of innate or supernatural ability, and whether it is "magical" or not is somewhat ambiguous.

My reason for asking is that Detect Magic seems to be a relatively low-level spell and thus makes Wild Shape (for espionage, surveillance, scouting, etc.) somewhat less dependable.

In another answer by Neil Slater, this excerpt seems applicable:

...the consensus in groups I have played in ... is that Detect Magic is equivalent to "Detect Spells, Spell-like Effects and Enchantments". That is, it will detect spells in progress, spell-like powers of monsters, and permanent enchantments on scrolls, and standard magic weapons. Under that interpretation, will not detect supernatural powers, such as a druid's Wild Shape...

Is there a more recent consensus on how this mechanic might work?

Finally, Detect Magic aside, in what other ways can a druid's Wild Shape be detected or nullified?

Answer 1

Truesight

A monster with Truesight can, out to a specific range, [...] perceive the original form of a Shapechanger or a creature that is transformed by magic.

This is supported by this answer.

Truesight can be obtained by casting the 6th level spell True Seeing, which lasts one hour without concentration. Needless to say this spell comes at a high cost and is the ultimate tool for finding a magically concealed intruder.

Detect Magic

Wild Shape is a magical effect:

Starting at 2nd Level, you can use your action to magically assume the shape of a beast that you have seen before.

therefore it can be detected by Detect Magic, which unambiguously states the following:

For the duration, you sense the presence of magic within 30 feet of you. If you sense magic in this way, you can use your action to see a faint aura around any visible creature or object in the area that bears magic, and you learn its school of magic, if any.

Is Wildshape useless for infiltration?

No. The basic implication here is that Wildshape is not an effective tool against magic users that are actively looking for an intruder. This does not mean that it's useless.

It's a pretty steep cost for a spell caster to continuously consume 6th level spell slots to cast True Seeing or 1st level spells slot to cast Detect Magic just in the off chance that a druid is nearby. A creature using the spell in this way is certain to run out of spell slots after a short period of time.

If, instead, they're using ritual casting for Detect Magic, they'll be continuously occupied and there will be 10 minute gaps between each casting. These gaps could be the perfect time for a Druid to sneak past them.

Patience is on the side of the Druid. They can simply wait while a spell caster exhausts both their time, resources, and patience looking for them, before casually sauntering past them in whatever discreet form they please.

Answer 2

It's a special case (it would only apply to some specific animal forms with an INT of 3 or lower), but casting Detect Thoughts could reveal that something is abnormal about the creature (though it wouldn't reveal a Druid in Wild Shape, specifically).

Since Detect Thoughts has no effect on creatures with INT 3 or lower, casting the spell on such a creature would normally have no effect. But if you start actually detecting some thoughts, then some response may be warranted.

This is an inferior solution to Detect Magic, already covered well by Andrendire, but for completeness' sake this is another (potentially) workable option.