Yeah, I've noticed that the skarv likes to sit on those poles.
When I was living in the arctic, I thought skarv was a typical arctic bird, so I was surprised encountering them further south. Once, when concentrated on "landing" the boat in a bit tricky wind, I heard a loud BANG. What did I hit now? Actually, it was birdstrike - a skarv had crashed with my mast! After I had tied up the boat I took the dhingy and collected the dead bird from the sea. I tried calling my mother to ask if it was edible, unfortunately she was busy - later I heard that it is indeed good to at it, as long as it's treated correctly - it's needed to bleed it dry as soon as possible, otherwise the meat will get a very bad fishy taste.
I have never tasted it, but my wife's uncle says it's good, almost like red meat. You can also smoke it with fine results I've heard.
They were almost extinct because the fishers hated them, but now they are everywhere and still protected. Like crows they shit the trees they inhabit in big colonies to death, and they eat an awful lot of fish so there have been discussion about allowing some hunt on them. As your mother said they should be good to eat.