Roberto,

A sign out there is an excellent idea, imo. Then, it's not Matt's or my word, or a "rumor" about NB being temporarily off limits. There is a sign and it "is fact". Also, there is no way an out of towner is going to know not to ride there without a sign. The rangers told us about a month ago that NB and the surrounding area would be closed mid April due to nesting and I made a couple posts about it, so this shouldn't be coming out of the blue or as a surprise. But, how would a guy from Minnesota know?

From the contact I have had with the rangers, they simply love having us in the park and have no desire to boot us out.
But, they also have birders with conflicting interests/concerns and this presents them with a challenge. Imo, if we show respect toward their situation and the park's natural residents, we will be in a win/win.
Jim Wilson, the Park Superintendent, is very approachable, nice and understanding. If someone takes it upon themselves to approach the rangers to arrange for a sign, I recommend talking with him. He is the one "who matters most" and he already has a very good impression of the kiting community.