Cross Breeding

Here is a video of some actual examples of successful cross bred animals. Remember, for every successful cross-bred animal there may be thousands of animals that did not survive. 

http://cms.watchknowlearn.org/Video.aspx?VideoID=30618&CategoryID=2783

Here are some real life issues with cross breeding

http://www.vu.edu.au/news/crossbreeding-with-domestic-ducks-a-major-threat-to-native-ducks