Ramblers, horse-riders and cyclists are being urged to minimise disruption to rare nesting birds in West Yorkshire by sticking to roads and footpaths.
The Moorland Association has made the plea for extra care until the nesting season finishes at the end of July.
Heather moorland provides a refuge for some of Britain's rarest and declining ground nesting birds, such as curlew, lapwing, merlin and snipe.
The association is also asking all visitors to keep their dogs on leads.
Chairman of the Moorland Association, Simon Bostock, says everyone must do their bit to protect the birds' future.