I recently removed a buckthorn from my small backyard as its growth pattern was impacting the performance of my solar PV electricity generating system, requiring never-ending pruning / trimming, while not providing me any privacy given the height of the canopy (~ 1.5 to 2 storeys high). I can attest that the squirrels used the leafy twigs to make their nests and that all sorts of birds (i.e., grackles, sparrows, robins, blue jays, and cardinals) appeared to be eating its berries.