The Friends of Ilkley Moor reported the theft of the signs, which were installed by Bradford Council in order to protect ground-nesting birds during the breeding season.

The Friends group supported the erection of additional signage close to ‘sensitive’ nesting sites at the top of Ilkley Moor, but say the majority of them have now been ‘ripped’ from their posts and removed within two weeks of being fixed in place.

As the moor, which is popular with walkers throughout the year, is open access land, dogs must be legally kept on a lead around livestock, and between March 1 and July 31 – the breeding season for birds – on a lead no more than two metres in length regardless of the presence of livestock.

In addition, the area is subject to a Public Spaces Protection Order, meaning fixed penalty notices can be issued to dog walkers who refuse to put their pet on a lead.

The rules are in place because the presence of loose and ‘roaming’ dogs can frighten birds into abandoning nests and their young, as well as injure sheep and cause them to miscarry lambs.

Farmers are also legally permitted to shoot dogs they consider to be worrying their livestock.

Ilkley Moor is protected because it is a vital habitat for species including curlew, lapwing, golden plover, merlin, short-eared owl and red grouse.

Bradford Council’s countryside and rights of way team confirmed that the signs will be reinstated and have reiterated their plea to users of Ilkley Moor to respect the environment and control their dogs.

Anyone who witnesses a sign being tampered with or records details such as a suspected vandal’s car registration number should contact the council.

Ilkley Moor: Signs warning that dogs must be kept on leads are stolen from Yorkshire moor by vandals just two weeks after being erected