In LA police can enter a home without a warrant if they hear an animal in distress.
A report of a dog crying in distress can constitute an emergency that justifies police entering a home without a warrant, a state appeals court ruled Thursday in upholding a Los Angeles County man's conviction for animal cruelty.
Police can conduct a search without a judge's approval "when an officer reasonably believes immediate warrantless entry into a residence is required to aid a live animal in distress," Presiding Justice Joan Dempsey Klein said in the 3-0 ruling.
Link:
http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2010/06/04/BA8Q1DPK7V.DTL