Run-on sentences are defined as the sentences when two independent sentences are inappropriately joined without proper punctuation or coordinating conjunction.
The given sentence would be characterized as a run-on as two independent clauses conveying complete thought are linked inadequately which creates a misleading effect. In order to rectify this error, the two sentences can be separated using a full stop for clarifying the meaning.
'The duck hunter set out his decoys in the shallow bay. Then he waited for the first real bird to fly.'
