These two journals contain not only reports of original research, but also general articles, announcements, and advertise events of interest to scientists. The great majority of articles are published in journals which relate to particular fields of science. Journals are a great source for current research and information on your subject. Journals are usually found through library research, although some are now in electronic, online versions. Library research will provide several sources of information of value.
Books are still a wonderful source of information.
It generally takes longer for new information to find acceptance into the field and into the books of the field. However, good solid information on our understanding of birds is presented in books and may be new to you. Books help create a fundamental understanding of your research area and provide a wide view of our understanding of the natural world. There are also a standardized protocol books, which are very useful. Internet searches are also valuable but remember, always evaluate the source of the information and determine how reliable that source is for information.