Dog walkers in Berkshire are being urged to keep their pets on leads to help protect rare ground-nesting birds and their offspring.
Nesting birds such as woodlark, skylark and lapwing on Greenham Common are easily scared by roaming dogs and often fly away until the threat has passed.
This leaves their eggs at risk from predators or to go cold and not hatch.
Three wardens will patrol the common over April and July. There will also be signs showing where pets can roam.
Jacky Akam, West Berkshire living landscape manager for the local Wildlife Trust, said: "The woodlark was once a relatively common and widespread breeding bird across our heathlands, but numbers plummeted.
"These endangered birds now need help to ensure population increases are maintained.
"Disturbance is a real issue for the woodlark and other ground-nesting birds."