This is obvious in the drought which caused 4 of every 5 medium ground finches to die, due to their inability to crack open the large seeds that were the only food available. Due to this change in food source, the finches with large beaks had a selective advantage, allowing them to survive the drought and have large beaks persist into future generations. The El Niño caused a similar selection event, but finches with small beaks had a selective advantage, as the seeds in abundance were small and soft. A variation in success was also observed in the 2003 drought, were medium ground finch with large beaks saw a significant reduction in population as they were not as efficient at opening large seeds as the large ground finches on the