The idea of studying knowledge as a shared resource that is subject to social dilemmas, within the framework of the commons approach is relatively recent (Hess & Ostrom, 2007). One of the approaches used in this framework is Institutional Analysis and Development (IAD) (Frischmann et al., 2014; Hess & Ostrom, 2007). IAD framework consists of a set of questions aimed at analyzing how resources are governed by examining its characteristics, rules, actors involved and patterns (Frischmann et al., 2014). This paper focuses on citizen science, which refers to the process of collecting and/or evaluating data by the people who are not scientists. These projects often have online collaborative structures and are a type of open movement organized around collective goals (Wiggins & Crowston, 2011). Previously, one of the most popular citizen science projects, Galaxy Zoo project was examined using IAD framework as a case of commons governance (Madison, 2014). In this paper we contribute to this field of research by examining and comparing two ornithology citizen science projects from Turkey, trakuş and eBird, with a knowledge commons point of view using IAD framework.