Amphibian Egg Mass Update

Thursday in the pond we explored new territory, circumnavigating the island which I have since dubbed "Goose Island". On previous trips to the pond there have always been Canada geese there, but this was my first time getting close enough to see that there are three nests on the island, all with eggs.
There were Northwestern salamander egg masses all around the island.

Northwest salamander egg mass

On the north side of the island, the aquatic vegetation is totally gone. Under the sediment the bottom feels very gravelly, so I think pond plants aren't fond of gravel. On the west side of the island, the wind picked up, kicking small waves that made forward visibility almost impossible. Looking behind me I had perfect visibility, as long as I wasn't looking at the cloud of sediment created by my footsteps. Back on the east side crossing to the mainland, we apparently didn't cross at the same spot. I was fine in my chest waders but my partner had hip waders and overtopped them. Reaching the shoreline through deep water with a sticky bottom was a long, tedious adventure. I was fighting a cold and Roger had wet legs so it seemed like a good place to end the day.
We'll try one more trip to the pond this week and that will likely be it for the season. Pond lilies are emerging, and a layer of pads on the surface means we can't see what's underneath. Last year's final egg hunt was May 7th and this year's plant cover seems on track to equal last year's growth.
After exiting the pond there were two dead shrews on the dirt path back to the cars. Who is killing them and why aren't they eating them?

Dead shrew in the path