The Isles of Scilly Wildlife Trust has responded to criticism of its decision to undertake maintenance work on a hide at Porth Hellick this month.
The Trust announced in August that it would be closing the Stephen Sussex Hide while its Ranger team replaced the old wooden bridge and hand rail.
Some users of the hide have complained that it will be unavailable in the lead-up to to the peak period for birdwatching next month.
The Wildlife Trust said: "It's disappointing, and demoralising for the team, that some members of our community, resident and visiting, are grumbling about the temporary closure of the Stephen Sussex Hide whilst vital maintenance works are undertaken.
"The hides are appreciated and used a great deal all year round. This is evident from the fantastic donations we've received, in the newly installed donation boxes, over the summer months; consequently there is never going to be a "good month" for a temporary closure to take place in terms of usage.
"We had hoped for greater understanding, trusting that users would bear the short-term inconvenience with grace; given that this work will help to secure the long-term future of one of our stunning nature sites, for all to enjoy.
"As a charity the Trust is heavily reliant on grant funding; donations, membership and legacies currently make up about 10-20% of our annual income. In an Island community, with limited financial resources, we are reliant on the same people to support the Trust as the Air Ambulance and the RNLI and we know that there is simply no competition. The Air Ambulance and RNLI both provide vital, lifesaving services to our community and the amounts raised locally on an annual basis for these two fantastic causes are astounding.
"It does mean, however, that to do things that are expected of us by our community (path clearance, boardwalk maintenance, looking after our archaeological heritage) restrictions are in place, due to the nature of where we obtain our funding. The Ranger Team endeavour to be flexible and innovative in terms of how they carry out this work but sometimes it just needs to be done when it needs to be done.
"Given the recent heavy rainfall it is possible that timescales may alter slightly in terms of the work being carried out on the Stephen Sussex Hide; however, as with all their work, the Ranger Team will endeavour to keep access restriction to a minimum in order to cause the least amount of inconvenience. We do hope to be able to stick to schedule!
"For those who want to keep up to date with progress we will be posting regular updates across our social media channels and if any delays are likely we will of course let people know."