Rabbit
Shares many of the traditions of the hare
Passing in front of you - good luck
Passing behind you - bad luck
Running down a street - a house will catch fire
Keeping a rabbit's foot - good luck
Rat
Most relate to the rat's association with death
It is believed that rats can predict death
Rats leaving a ship - the ship will sink
Rats seen boarding a ship - lucky
Rats leaving a house - A death is iminent
A sudden arrival of rats in a house - the occupants will move soon, or (in Scotland) an occupant will come into money
An increase in numbers - an omen of war
Raven
Seen near a sick person - no recovery
Welsh belief - A raven on a chimney is good luck to those within
Ravens leaving The Tower of London - The United Kingdom will fall
Flying towards the sun - fine weather
Robin
Killing a robin - exremely bad luck
Causing a robin injury - a similar injury to the perpetrator
Entering a house or church - omen of death
Seagull
Killing a seagull - bad luck
Seen far inland - bad weather
Sheep
A shepherd counting his flock - bad luck
Sitting still on the grass - fine weather
Walking about and bleating - bad weather
Snake
Hanging a snake skin from the rafters - protection from fire
Crossing your path - unlucky
Carrying a snake skin - protection against illness
Carrying a snake's tooth - protection against fever and luck in gambling
Wearing an emerald - protection against snake bites
Sparrow
believed to embody the souls of the dead
Killing a sparrow - the tree it lived in will die
Hearing a sparrow call - rain
Spider
Killing a spider - very bad luck
Seen running over clothes - a new set of clothes
Keeping a money spider in the pocket or purse - attraction of money
Stork
Killing a stork - bad luck
Building a nest on the roof - good omen
Seeing two storks - omen of pregnancy
Swallow
Herald of the summer
Killing a swallow - bad luck
Nesting on the roof - protection especially against lightning and fire
Storms will accompany the arrival and departure of swallows
information sources:
"Dictionary of superstitions" by David Pickering
"The encuclopedia of superstitions" by Christina Hole