Darn that is sad. Poor bulldog...................got caught napping!
I have used a wide weave net over the pond for years now. It does not trap the small birds, the frogs, the bugs etc. The dragon flies even got stuck when I used a smaller weave net. Mine is around 2ish feet over the water, the heron can not strike through it and reach the fish.
I had herons visiting every day for a few years. We are in their flight path. Since I put up the net they have left the pond alone. I did forget to cover my hot tub pond, loss every fan tail in it, around 9, when I left to head to Florida in Feb. Had some ice on it, but melted spots here and there. Also loss some fish in the 1000 gallon tank, that net started falling apart, forgot to fix it.
So unless I want population control, the net stays on.