Thousands of nature’s tiniest engineers are hard at work at the Maroochy Wetlands Sanctuary, where bright orange “hard hats” and busy excavation projects are drawing the attention of visitors. The industrious workers are not construction crews but fiddler crabs, one of the sanctuary’s most fascinating residents, currently bustling across the mudflats as they dig burrows throughout the mangrove ecosystem. The colourful crustaceans are among the m…