terms for animal groups

Mammals
Apes - A shrewdness
Asses - A pace
Badgers - A cete
Bats - A colony
Bears - A sloth, sleuth
Buffalo -  A gang, an obstinacy (I suspect these refer to old world buffalo; use "herd" for American bison)
Cats - A clowder, a pounce; for kittens...A kindle, litter, an intrigue
Cattle - A drove, herd
Deer - A herd, bevy (refers only to roe deer)
Dogs - A litter (young), pack (wild), cowardice (of curs); specific to hounds...A cry, mute, pack, kennel
Elephants - A herd
Elk - A gang
Ferrets - A business
Fox - A leash, skulk, earth
Giraffes - A tower
Goats - A tribe, trip
Gorillas - A band
Hippopotamuses - A bloat
Horses - A team, harras, rag (for colts), stud (a group of horses belonging to a single owner, string (ponies)  
Hyenas - A cackle
Kangaroos - A troop
Leopards - A leap
Lions - A pride
Martens - A richness
Moles - A labor
Monkeys - A troop, barrel
Mules - A pack, span, barren  
Otters  - A romp
Oxen - A team, yoke
Pigs  - A drift, drove, litter (young), sounder (of swine), team, passel (of hogs), singular (refers to a group of boars)
Porcupines - A prickle
Rabbits - A colony, warren, nest, herd (domestic only), litter (young); specific to hares...A down, husk  
Rhinoceroses - A crash
Seals  - A pod, herd
Sheep - A drove, flock, herd
Squirrels - A dray, scurry  
Tigers  - A streak
Whales - A pod, gam, herd
Wolves - A pack, rout or route (when in movement)

Birds
Birds in general  A flight (in the air), flock (on the ground), volary, brace (generally for gamebirds or waterfowl, referring to a pair or couple killed by a hunter)
Bitterns -  A sedge
Buzzards -  A wake
Bobolinks  - A chain
Chicks (of many species)  A brood; clutch  
Coots - A cover
Cormorants -  A gulp
Cranes -  A sedge
Crows -  A murder, horde
Dotterel -  A trip
Doves -  A dule, pitying (specific to turtle doves)  
Ducks -  A brace, flock (in flight), raft (on water) team, paddling (on water), badling
Eagles -  A convocation
Finches -  A charm
Flamingos -  A stand
Geese -  A flock, gaggle (on the ground), skein (in flight)  
Grouse - A pack (in late season)  
Gulls - A colony  
Hawks - A cast, kettle (flying in large numbers), boil (two or more spiraling in flight)
Herons - A sedge, a siege
Jays - A party, scold
Lapwings - A deceit
Larks - An exaltation
Mallards - A sord (in flight), brace
Magpies - A tiding, gulp, murder, charm
Nightingales - A watch  
Owls - A parliament  
Parrots - A company  
Partridge - A covey
Peacocks - A muster, an ostentation
Penguins - A colony
Pheasant - A nest, nide (a brood), nye, bouquet
Plovers - A congregation, wing (in flight)
Ptarmigans - A covey  
Rooks - A building
Quail - A bevy, covey
Ravens - An unkindness
Snipe - A walk, a wisp
Sparrows - A host
Starlings - A murmuration
Storks - A mustering
Swallows - A flight
Swans - A bevy, wedge (in flight)
Teal - A spring
Turkeys - A rafter, gang
Widgeons -  A company
Woodcocks - A fall
Woodpeckers - A descent

Reptiles and Amphibians
Crocodiles  A bask
Frogs - An army  
Toads - A knot
Turtles - A bale, nest
Snakes, vipers - A nest

Fish
Fish in general  A draft, nest, school, shoal (some authors claim that the common "school" is a corruption of shoal, and therefore incorrect)
Bass - A shoal
Herring - an army
Sharks - a shiver
Trout  A hover

Invertebrates
Ants  A colony
Bees  A grist, hive, swarm
Caterpillars  An army
Clams  A bed
Cockroaches  An intrusion
Flies  A business
Gnats  A cloud, horde
Grasshoppers  A cloud
Hornets  A nest
Jellyfish  A smack
Locusts  A plague
Oysters  A bed

If your hoping to see the correct usage here, well, don't.

Why did you post this?

Next time I'm beset by a flock of ravens, I'll at least know that the proper term is "unkindness".

Rooks - A building

Now it's all clear to me