Doing research this afternoon, I discovered this wonderful compilation by Terry Ross (tross@ubalt.edu) and thought it fascinating enough to share. It’s posted through the Baltimore Bird Club but I offer it here.
Just a quick scan, creates favourites. Some are melancholy: a murmuration of starlings; a pitying of turtle doves. Others lavish: an ostentation of peacocks; a parliament of owls.
Meanwhile, a siege of herons is nesting in the tall trees beside the nearby sea, and I often  succomb to a charm of finches. Thank you, Terry Ross, for this.

Group Names for Birds: A Partial List

A bevy of quail
A bouquet of pheasants [when flushed]
A brood of hens
A building of rooks
A cast of hawks [or falcons]
A charm of finches
A colony of penguins
A company of parrots
A congregation of plovers
A cover of coots
A covey of partridges [or grouse or ptarmigans]
A deceit of lapwings
A descent of woodpeckers
A dissimulation of birds
A dole of doves
An exaltation of larks
A fall of woodcocks
A flight of swallows [or doves, goshawks, or cormorants]
A gaggle of geese [wild or domesticated]
A host of sparrows
A kettle of hawks [riding a thermal]
A murmuration of starlings
A murder of crows
A muster of storks
A nye of pheasants [on the ground]
An ostentation of peacocks
A paddling of ducks [on the water]
A parliament of owls
A party of jays
A peep of chickens
A pitying of turtledoves
A raft of ducks
A rafter of turkeys
A siege of herons
A skein of geese [in flight]
A sord of mallards
A spring of teal
A tidings of magpies
A trip of dotterel
An unkindness of ravens
A watch of nightingales
A wedge of swans [or geese, flying in a “V”]
A wisp of snipe

Any of these group names may properly be used by birders who wish to display their erudition, although it is probably linguistically inaccurate (and it certainly is bad manners) to upbraid someone who refers to “a bunch of ravens” by saying, “Surely you mean `an unkindness of ravens,’ my good fellow.” Most of these terms date back at least 500 years. Some of them have been in continuous use since then; others have gone out of fashion and been resurrected in the last century or two; still others only exist on lists.

Most of these terms are listed in James Lipton’s An Exaltation of Larks. Lipton’s list is substantially based on very old sources. There were manuscript lists of group names in the 15th century, and these lists appeared in some of the first books printed in England. Many of them make their first appearance in John Lydgate’s Debate between the Horse, Goose, and Sheep (1440); and Lydgate’s terms along with others appear in The Book of Hawking and Hunting (also known as The Book of St. Albans) by Dame Juliana Barnes (1486). Whether Lydgate and Barnes coined any of these terms, or whether they were setting down the terms that were considered proper in their day is not known. Many of the terms did catch on, and the lists they appeared on were frequently reprinted.

The best source I know for investigating the histories of English words is the Oxford English Dictionary. Unfortunately, on the question whether these terms ever were or still are appropriate, the OED is not entirely helpful. To make sense of the matter, I have placed the group names into groups–

GROUP A–The following group names are standard:
A bevy of quail
A bouquet of pheasants
A brood of hens
A cast of hawks
A charm of finches
A covey of partridges
A flight of swallows
A gaggle of geese
A nye of pheasants
A siege of herons
A skein of geese
A trip of dotterel
A wisp of snipe

GROUP B–These terms are not group names for a particular type of bird, but have been commonly used for many different types:
Colony
Company
Flock
Parliament
Party

GROUP C–These terms are archaic; they were once obsolete, but they have been revived somewhat in the 19th or 20th centuries:
A building of rooks
A murmuration of starlings
A muster of peacocks
A peep of chickens
A sord of mallards
A spring of teal
A watch of nightingales

GROUP D–These terms are obsolete; they appeared on the old lists, but almost nobody has used them in centuries:
A congregation of plovers
A dissimulation of birds
A dole of doves
A fall of woodcock
A host of sparrows
A paddling of ducks
An unkindness of ravens

GROUP E–These terms are not in the OED at all as group names for birds:
A cover of coots
A kettle of hawks
A murder of crows
An ostentation of peacocks
A pitying of turtledoves
A rafter of turkeys
A tidings of magpies

My categories are imprecise, but they provide some guidance about usage. Have no qualms about using any of the terms in group A; use the terms in group B for any group of birds that seems apt; use the terms in groups C and D only if you don’t mind being thought pedantic or literary; avoid the terms in group E unless you know something the OED doesn’t.
Alas, the OED itself is not totally reliable: the word “kettle” (as both a noun and a verb) has been used by hawk watchers for many years, and it has often appeared in print; the OED editors obviously are not birders. It may well be that the other terms in group E appear on the 15th-century lists and were simply missed.