Holy Loch Nature Reserve comprises around 24 acres of ungrazed coastal marsh, vegetated gravel and (damp) "carr" woodland, most of which has naturally regenerated on top of a now disused council roads waste midden. These are intersected by several burns which flow from the hills into the Holy Loch. Over 20 small pools on the marsh support an array of water plants and animals. Some of the pools are permanent while others are ephemeral. At the highest spring tides, most of the marsh is inundated by the sea.

The reserve is home to at least 1500 species that live in a stable, predictable and mind-blowingly complex web of life which we are only just beginning to understand.

Birds and mammals are the main reason why so many people visit the reserve, but they depend on the stability and predictability of this huge community of species. The many residents are joined at different times of the year by migrants. Consequently, over 120 species of bird use the reserve at some time during the year, including Kingfisher, Osprey, Little Egret and Peregrine. Occasionally, a White-tailed Eagle overhead may spook the birds below, and cause them all to take to the air. Small populations of Curlew, Redshank, Teal and Wigeon overwinter around the loch before heading for their breeding grounds in late Spring and Summer. At around this time, species such as Willow Warbler and Whitethroat arrive from Africa to breed.

An easy path to an accessible birdwatching hide, with bird feeders, makes the reserve suitable for anyone. The best time to visit is 1 hour either side of high tide.

Climate change presents a growing threat to the reserve and its residents, through rising sea levels and growing extremes of temperatures, rainfall and wind strength. The reserve is a partner in the Darwin Tree of Life initiative.