You need to find someone who has written on the topic of ethnobiology. The best place to start is with a database, since you're probably not familiar with many ethnobiologists. Databases index hundreds to thousands of journals, and they may only link to an abstract which summarizes the article opposed to the complete article. The databases basically tell you what literature exists. Remember that they will retrieve any information that you query, so you may want to use generic or perhaps fewer terms if you get a limited number of search results.
1. After you have selected an author, see what they've written.
For example, check for the author Wade Davis in the library catalog to see if he has written books, and the subject-specific database to check for articles he's written.
2. Check if other people have cited their work.
For example, Wade Davis wrote the book Passage of Darkness: the Ethnobiology of the Haitian Zombie. Check Google Scholar to see if anyone has cited this book (Google Scholar has it currently listed with 82 citations). The database Science Citation Index is another useful resource for exploring article citations. Davis also wrote "The ethnomedicine of the waorani of Amazonian Ecuador" and when you search ohq database displays other people's citation
3. Some articles list the instituion to which they are currently associated.
They may change from institution from institution, but they may also have a personal web page with additional information, such as their publications, research interests, etc.
4. Search the Internet for your person's "CV" or biography (see Wade Davis example). This will give you a list of the employment history, education, and publications.
5. Use some reference books to find professional information about the person you're researching. Keep in mind that there may not be much info on the person you choose to research.