What is the verbs in the following sentences:

this one is a muscovy.

is that a sandhill crane?

michele is a very good singer.

This one is a Muscovy.  'Is' is the linking verb.

Is that a sandhill crane?  'Is' is the linking verb. 

Michele is a very good singer.  'Is' is the linking verb.

Each sentence has the word "is" and that word is known as a helping/linking verb.

‘the resulting drop in pressure would be detected by the soviets.’