Bad luck

BLACKBIRD
If this bird makes a nest on your roof, this is said to be a traditional sign of good luck. In fact most people believed that if this bird nests anywhere near the house it a positive sign. Seeing the sight of two together is unusual and a sign of good luck as the blackbird is very territorial.

DOVE
Seen by many as a sacred bird since ancient times as the dove is the one bird into which the Devil cannot transform. The messenger of 'Venus', Goddess of Love, the dove is associated with lovers. For Indians the dove is traditionally believed to contain the soul of a lover, and that to kill one would bring misfortune. Miners though see the bird as one of ill omen and it is reputedly too dangerous to go underground after seeing this bird near a pitshaft. To have one tapping on the window or flying near the room of a sick person is also believed by some to be an omen of death, as is to see one circling a house. Today the dove is an international symbol of peace and also a Christian symbol of the 'Holy Spirit'. The dove is one bird into which reputedly a witch cannot transform.

DUCK
If this bird hisses or quacks more than normal it is said that rain is on the way. If the bird lays any dun-colored eggs it should be destroyed, along with the eggs, according to a traditional English belief that indicates that misfortune will follow should this event happen. At this and any time hanging a duck upside down is asserted to assure that negative energies and spirits can fall from it.

OWL
A bird with a poor reputation despite being known for being extremely wise hence the expression being a 'wise old owl'. Perhaps this stems from the fact that the owl leads a nocturnal and solitary existence and that the night has long been associated with the time when darker forces and negative energies are present. To see one by day is unlucky and to experience one flying around the house at night signals that death is present, which is thought to stem back to Roman times when the historian 'Pliny' in AD 77 was quoted as saying the bird was 'most execrable and accursed' and always brought bad news. Should an owl brush its wings against a window pain or be seen perching for a considerable length of time on a roof then it is traditionally believed that illness and even death is present within. To look into an owl's nest is reputed to leave the observer with a sad and morose soul. According to an old Welsh tradition if you hear an owl hooting amongst a densely built up area then a female in the locality is said to have just lost her virginity! To hear the hoot of the owl when pregnant, it is traditionally believed in France, means that the baby will be a girl. In Germany if one is heard as a child is being born then the life will be an unhappy one. In the Southern states of America an old traditional rhyme tells of the cry of the owl:

'When you hear the screech owl, honey, in the sweet gum tree,
It's a sign as sure as you're born a death is bound to be;
Unless you put the shovel in the fire mighty quick,
For to conjure that old screech owl, take care the one that's sick.'

A dead owl has served many purposes including mixing some of the flesh with boar's grease as an ointment to ease the pain of gout. Owl broth was once used to feed children to avoid whooping cough according to British tradition, perhaps because the owl itself never suffered in pain when making a similar sound. The eggs were also once thought to help prevent epilepsy, bad sight (for obvious reasons) and more amusingly to bring drunks back to their senses.

http://www.shawcreekbirdsupply.com/folklore_superstitions.htm