Our little home in Chula Vista has apparently been shared from time immemorial with the swallows. They nest in sconce type light fixtures on our entry porch. They make a big mess. They are not easily discouraged. I cleaned all the nests and messes and hung out a No Trespassing sign using my best efforts at bird language. They failed to get the message. So after hollering at them and stamping our feet without success, I soaked them with the hose. That worked but only for a while. Our rental agents said that swallows couldn't abide the smell of diesel oil. So I bought some diesel oil and fuelled their nests. It is true - swallows don't like the smell of diesel oil in their bed. None of us do. So they wouldn't nest in the oil, but they sent their most capable spokesbird to plead their case. He (or she) flew in, sat on the edge of the porch chairs and stared at me. Also, we had been leaving the doors open because of very hot spring weather, and this bird flew in the house and out again to get my attention. I allowed as how it must be a reincarnated friend or relative, so I attempted a conversation with him-her-it. The damned thing talked back. But since my skill at bird language is even worse than my Spanish, the conversation remained one sided. After one full week of this game, I concluded that the bird was probably a reincarnation of one of my wife's stubborn Dutch relatives, and I gave up. I quit dieseling one of the lamps, and the swallows returned as they always do.