GMAT Critical Reasoning (CR) | Re: The dwarf masked owl, a rare migratory bird of prey, normally makes it

I am in trouble in applying negation technique here. Would you please help me?

D. The dwarf masked owl will not make its winter home on the Baja peninsula only if that region contains no spiny cacti.
Negated Statement: The dwarf masked owl will not make its winter home on the Baja peninsula only if that region contains spiny cacti.
Breakdown the conclusion. So, it is a valid assumption.

E. Suitable nesting sites must be present where the dwarf masked owl makes its winter home.
Negated Statement:
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