The Gulf Islands National Park Reserve has published a reminder to users of the park that part of Sidney Island -- the park area north of the prominent fence line -- is closed to the public from November 1st 2014 through February 28, 2015. You can find notice of this annual closure in the Times-Colonist.
The park area south of the day-use area on Sidney Spit is closed during the winter for public safety reasons, to facilitate hunting by First Nations during this time. The fallow deer on Sidney Island have become so numerous that a cull is necessary to reduce their numbers.
Though the day-use area of the island is still open to the public, and the mooring buoys and the spit itself are available for boaters to use, it is a good idea for kayakers and other boat users to plan visiting other parts of GINPR until the closure is lifted March 1st.