The NOU has three sections which you can (also separately) join:
Dutch Seabirds Group (NZG):
Focuses on stimulating seabird research the exchange of information. The section has it's own magazine SULA containing articles published in Dutch, but with English summaries and captions. The section also participates in the freely available journal Marine Ornithology (www.marineornithology.org). More information is available on the website.
Dutch Waders Group (NSWG): focuses on research and protection of waders in the Netherlands. Organizes an annual seminar in cooperation with the WIWO. To receive information email: gerritjgerritsen@gmail.com
Dutch Ornithologists Club (CNV): Organizes lectures and excursions. More information and an opportunity to register are available on the website.