In this respect, devils have earned the gratitude of Tasmanian farmers, as the speed at which they clean a carcass helps prevent the spread of insects that might otherwise harm livestock. Some of these dead animals are disposed of when the devils haul off the excess feed back to their residence to continue eating at a later time. The diet of a devil can vary substantially for males and females, and seasonally, according to studies at Cradle Mountain. In winter, males prefer medium mammals over larger ones, with a ratio of 4:5, but in summer, they prefer larger prey in a 7:2 ratio. These two categories accounted for more than 95% of the diet. Females are less inclined to target large prey, but have the same seasonal bias. In winter, large and medium mammals account for 25% and 58% each, with 7% small mammals and 10% birds. In summer, the first two categories account for 61% and 37% respectively. Juvenile devils are sometimes known to climb trees; in addition to small vertebrates and invertebrates, juveniles climb trees to eat grubs and birds' eggs. Juveniles have also been observed climbing into nests and capturing birds. Throughout the year, adult devils derive 16.2% of their biomass intake from arboreal species, almost all of which is possum meat, just 1.0% being large birds. From February to July, subadult devils derive 35.8% of their biomass intake from arboreal life, 12.2% being small birds and 23.2% being possums. Female devils in winter source 40.0% of their intake from arboreal species, including 26.7% from possums and 8.9% from various birds. Not all of these animals were caught while they were in trees, but this high figure for females, which is higher than for male spotted-tailed quolls during the same season, is unusual, as the devil has inferior tree climbing skills. Although they hunt alone, there have been unsubstantiated claims of communal hunting, where one devil drives prey out of its habitat and an accomplice attacks. Eating is a social event for the Tasmanian devil. This combination of a solitary animal that eats communally makes the devil unique among carnivores. Much of the noise attributed to the animal is a result of raucous communal eating, at which up to 12 individuals can gather, although groups of two to five are common; it can often be heard several kilometres away. This has been interpreted as notifications to colleagues