Without knowing what kind of trees were in the courtyard before, I can't help on any legitimate reasons for removing them. However, pine should support a large number of species, and, in my experience, should provide even better nesting potential given some time. Of course, spruce, fir, or hemlock would do the job even better, but those tend to prefer northern ranges, so sometimes pine is what's available.

I agree that the lower maintenance excuse is no excuse - what can be lower maintainence then allowing a natural woodland to form, by leaving leaves and limbs where they fall, so that they can rot away and help the trees grow healthier?