Eradication of feral goats on Guadalupe Island: absence confirmation

Insular ecosystems all over the world have been negatively affected by the introduction of ungulates, and it is due to the dramatic impacts that extensive control/eradication programmes have been undertaken. Eradication programmes using sophisticated techniques were recently carried out on Mexican islands. However, the phase of absence confirmation is facing the challenges seen elsewhere: how much effort is needed to confirm success? We present the case of Guadalupe Island in the Mexican Pacific. Eradication of feral goats (Capra hircus) was conducted on this volcanic island of 250 km2 from 2002-2006. Since 2007 we have focussed on confirming absence through use of Judas goats. We discuss our results to date and how future assessments can be improved.