Denis worked as an assistant on several landbird projects in Galapagos, including the project to conserve the critically endangered Mangrove Finch.

In 2018, he graduated from a Masters program at the University of Vienna. His research was focused on understanding the impact of Philornis downsi on the Little Vermilion Flycatcher.

Denis searched for natural enemies, specifically parasitic wasps, that could be used in a biological control program against Philornis downsi. This work was on mainland Ecuador and was in conjunction with our collaborators at University of Minnesota, ESPOL, and the National Biodiversity Institute.