Residents in the suburbs of Sydney, Australia, are in the midst of an escalating feud with a neighboring population of wild sulphur-crested cockatoos (Cacatua galerita) over an unlikely prize: household trash. While this conflict may sound comical, researchers report that it shows all the signs of an "innovation arms race," in which two species become trapped in a cycle of behavioral changes as they continually try to one-up or outthink one another. The sharp-witted cockatoos have earned the unflattering nickname "trash parrots" after learning to open up flip-top garbage bins to pillage their contents. In 2018, videos shared online showed...