This comes from what I posted on our sister site esoteric magick I thought we should get a good start (:
I have grown up around legends of this, the stories are everywhere from mexico, to mid texas, i think southern califonia too maybe but not sure if that is true...
As the story goes La lechuza is an evil witch that can transform into a huge bird usualy an owl about 5 to six feet tall, and when the Lechuza wants you it comes after and kills you suposedly, or you can go outside and at midnight whistle 3 times and if you hear a whistle back that means the lechuza heard you and will eventually come after you so they say. they say that if you pray in spanish the hail mary backwards and cuss in spanish at it that it will go away, as funny as that sounds to me i have heard the same thing many times. they say that the medicine men of mexico can walk outside where a La Lechuza is said to be and say some type of prayer and the lechuza will drop out of the tree dead...
La Lechuza translates to Owl in spanish, alot of mexican superstion of fearing the Owl as a bad omen comes from the mayan, they thought of the Owl as a bad omen also.
Here is a story that i heard not to long ago.
When Jorge was 13, he is now 54, he was playing with his 2 sisters in the back yard of there house near the honey bowl in uvalde texas. as they were playing outside there was a loud whistle seeming to come form nowhere, but they knew what it was he told me "It was La Lechuza, our mom told us never to whistle back but my sister allways did the oppisite of what our mom told us" he told me one of his sisters whistled and nothing happend so she yelled out into the darkness "La Lechuza your not real! Why dont you come to my house in the morning for some breakfast you fairy tale!" and he said his sister began to laugh and there mom came out side and told them to come in. well the next morning all the kids where at the table eating breakfast when there was a knock on their kitchen door, at that moment all the kids stopped eating and looked at the door, their mom open the door and there was an old woman standing there dressed in black. jorge said he heard his mom say Dios mio! and then she proceded to tel the woman that she needs to leave and she didnt say it nicely eaither the old lady said "But your daughter invited me to Breakfast last night! I am no Fairy Tale!" his mom slamed the door shut and to make a long story short his sister got a beating of a life time for that. he said for a month afterwards his mom would get terrified at night and they were not allowed to go out passed dark. this story came from a guy ive known for a while.
there ya go