The aim of the BIRDS workshop (Bridging the Gap between Information Science, Information Retrieval and Data Science) is to bring together the Data Science, Information Retrieval, Information Science and HCI communities. BIRDS 2021 is the second in a series of workshops and was held in conjunction with CHIIR 2021, following a successful event at SIGIR 2020. It consisted of a selection of accepted papers and invited talks. This article reports on BIRDS 2021, provides a discussion of topics, tasks, approaches and data sets and an outline of future directions for interdisciplinary work.