Tweeties have been quite witty in their picks for a new collective
noun to associate with kingfishers. One might wonder if such a noun
does not already exist. However, an authoritative book on the
development of collective nouns in English is "An Exaltation of
Larks" by James Lipton, published in 1968 and still in print, does
not identify one for kingfishers. The book covers terms that were at
one time either in general use as the only proper term for a "group
of whatever beast, fish, fowl or insect it designated, or had
acquired sufficient currency to warrant its inclusion in a list with
the well-established hunting terms." So, off to the internet.

The Wiktionary Free Encyclopedia has a page full of collective nouns
for various birds and others. For kingfishers it lists
concentration, realm, rattle, and clique. Another search turns up a
variety of bird-related web sites that refer to either concentrations
or cliques of kingfishers. It's difficult to stop grazing once you
find lists of unique ways to describe groups of birds. Our language
is rich indeed. As an aside, among the several collective nouns
associated with starlings, I prefer a vulgarity of starlings. I
couldn't think of a more appropriate description if I pondered it for
the ages.

Carol Riddell
Edmonds