Jersey Water says it's 'exploring other options' and will decide later this month whether to reopen part of Queen's Valley reservoir that has been plagued by rats.
The top car park has been shut since April and remains closed because some people are still feeding the wildlife, despite repeated pleas not to.
The rodents keep returning - disrupting the balance of nature of the site, drawing flocks of seagulls that are attacking duckling and damaging nests and duck eggs.
Mark Bowden is from Jersey Water says they are struggling to resolve the situation:
"We've taken as many measures as are reasonable at this stage to try and head the problem off, but it has not been successful. We have some very persistent feeders of the wildlife.
"We were trying to break the cycle of behaviour which is leading to this problem. We have explored a number of other routes, but it is more difficult than you might imagine just to take direct action against this kind of activity.
"It's really disappointing, We would just ask the public to please bear with us, have patience. We are looking to get things reopened as soon as we possibly can."
Last November, signs asking people not to feed the birds were torn down within days.
Other access routes to the reservoir are open. Jersey Water says it will issue another update about the top car park before the end of the month.
It says there is no risk to the water quality of the treated water supplied to the public.
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