Carl currently lives in Bogotá. He has been birding since the age of seven and first branched out onto the international scene at the age of 14 with a trip to the Austrian Alps. In the late 1980s he spent 8 months birding and working in the United States, but it was in 1991, when he was a member of a successful university expedition to the Choco biogeographical region of Colombia (which resulted in the discovery of the Choco Vireo) that he was first attracted to this part of South America. After graduating in Environmental Science in 1994, he moved to live in Cali to teach Biology. Since then he has travelled extensively in Colombia and has been a pioneer in leading successful tours there since 1995. He has also travelled throughout Europe, Southeast Asia and Brazil. He has published many records from his travels.
Carl was a founder member of the Neotropical Bird Club and has been a council member since 1997. He was club Chairman between 2003 and 2008.