Work was due to begin this week on demolishing Prestatyn Community Hospital which closed two years ago.
But now National Resources Wales has ruled that because seagulls are nesting on the roof, the demolition must be put on hold until the chicks have  flown.
Developers Pure Residential and Commercial have bought the site and lodged plans for apartments and houses.
Seagulls have come to the aid of campaigners fighting to save a former hospital from immediate demolition.