Sounds close to what my Zippy does every day, except Zippy does it real fast, for a much longer time period and closer together like a goose at the park when we were kids(the city got rid of all the domesticated geese and ducks years ago). Seems to be associated with him getting a bit excited in our case. We verbally play it down with him, we don't want him feeling our concern. He even wags his tail while he honks! Wonk wonk wonk!
