It appears to me to be an old style DV 100, which unfortunately for you they dont make it or parts for any longer. Whats more, the body is probably cracked. I think you'll end up having to cut out the offending valve and replace it with a new on. From what it looks like in the photo, there is at least one other valve adjacent to it, so you may as well relpace it while you are in there because chances are that it will fail sooner as opposed to later. All Wet

Speaking of birds, I just had quite an interesting encounter. I am trying to incorporate some very nice used carob bricks into my BBQ which is already built into some very large rocks adjacent to my pond. It is very challenging to try and meld the two materials together. I am totally engrossed trying to figure it out and out of nowhere comes a loud whoosh and a thud and an immature yet still very sizeable bald eagle flopping around at my feet. I'm not sure what attracted him, perhaps my koi but maybe he dove, saw me and tried to swoop out. He flew right into the glass rail of my deck and knocked himself cookoo. I calmly talked him through it until the cobwebs subsided and he was able to fly off to hunt another day. You talk about an adrenaline rush!!!!!! Here's a picture of the BBQ I was working on. I had just demo-ed the fake brick off the front when the eagle hit the glass panel on the deck stairs. Here is a link that might be useful:

Hmmm....I went through Cornell's Shorebird calls and the closest I could get was a Sora. Supposedly they summer here.

Its a duck, a green wing teal I believe. Birds have a number of predators, small and medium mammals, other birds, reptiles. Could be a hawk or owl, or a cat or fox or raccoon. Squirrels even will raid nests I believe.