Slaty grey snakes (Stegonotus cucullatus) are medium to large members of the Colubridae that are common throughout the eastern and northern tropics of Australia. Although intensive field studies have been conducted on populations in the Northern Territory for over 10 years, no ecological data have been presented on free-ranging specimens of populations inhabiting tropical north Queensland. During a 10-year period we collected opportunistic data on 120 free-ranging specimens from the seasonally Wet Tropics in north Queensland. These snakes provided data on body sizes, activity times, food habits and reproduction. Male S. cucullatus were larger than females and had larger heads. More snakes were found during the warmer, humid parts of the year (wet season). S. cucullatus ate a wide range of vertebrate prey, including reptile eggs that were obtained seasonally. Females produced one clutch per year, and no relationship was found between maternal snout–vent length and clutch size.