Participation in Open Source Software (OSS) projects offers real software development experience for students and other newcomers seeking to develop their skills. However, onboarding to an OSS project brings various challenges, including finding a suitable task among various open issues. Selecting an appropriate starter task requires newcomers to identify the skills needed to solve a project issue and avoiding tasks too far from their skill set. However, little is known about how effective newcomers are in identifying the skills needed to resolve an issue. We asked 154 undergrad students to evaluate issues from OSS projects and infer the skills needed to contribute. Students reported a total of 94 skills, which we classified into 10 categories. We compared the students' answers to those collected from 6 professional developers. In general, students misidentified and missed several skills (f-measure=0.37). Students had results closer to professional developers for skills related to database, operating infrastructure, programming concepts, and programming language, and they had worse results in identifying skills related to debugging and program comprehension. Our results can help educators who seek to use OSS as part of their courses and OSS communities that want to label newcomer-friendly issues to facilitate onboarding of new contributors.