There is a well known nature reserve very nearby, "het Zwin", where they organize tours with professional guides (free/groups/private/..., can be in Dutch, in French, maybe also in English, not sure), some of them more specialized on birds. It might be worth calling/emailing them to ask, and of course to pay the site a visit.The place is worth going to (of course also depending on the season). It’s quite special due to the free play the sea tides still have on the estuary.
Visit the Zwin Nature Parc | Zwin Natuur Park
I have a very good memory of a.o. two guided visits there, one a regular tour of the site, another an early-morning birding visit. Maybe I can find back the name and contact info of the guide. If so, I'll PM you her name.
In which language(s) could the guiding take place?