Report 8463: Fisherman hears afternoon scream at Lake Alpine

I was done working for the day. I had my fishing pole with me this afternoon, hoping I would have time to do some fishing at Lake Alpine. I was fishing for about a half hour when I heard these strange howls form a distance that lasted for about 20 seconds, it repeated at least 3 or 4 times. I would say the howls where at least a quarter of a mile away. There were 2 people fishing on the lake at the time. The closet person was about 1000 feet away from me. I am very familiar with animal vocalization in the area. The howls where not from black bears, mountain lions or coyotes. Nor where any birds calls. I am a avid birder and I known my bird calls.