Syntactic blends

[James A. Landau]

A couple of days ago there was a newspaper story (unfortunately I did not
keep it) about a bear that had been raiding David Letterman's country home.  The
bear was caught and transported a considerable distance in hopes that it would
"den up" and not return to David Letterman's neighborhood.

Would "den up" be a syntactic blend, from "den" + perhaps "build up"?

       - James A. Landau