A Bless of water voles?

The concept for collective nouns originated back in the 15th century in the Book of Saint Albans and some of them - a pride of lions, a shoal of fish and a pod of dolphins - have made it into regular use.
Yet some seem just bizarre - an unkindness of ravens, an ostentation of peacocks and fluther of jellyfish - and are unlikely to make it into a typical conversation.

The collective name for voles is rather dull - a colony - and there isn't one specifically for water voles. A conversation on twitter suggested a plop and a nibble and these are good descriptive words for the behaviour for water voles, but maybe they are not obscure enough for a collective noun. 
I prefer 'a bless of water voles' as this is the word quite often said when someone sees one of these small, endearing, yet endangered mammals.

And so far this year, there has been a big bless along the Ock.

Source: Wikipedia