It is also extremely fond of otters, which it consumes in large quantities. In its favoured bird manifestation the boobrie resembles a gigantic great northern diver or cormorant, but with white markings. According to folklorist Campbell of Islay, a detailed account of its dimensions provided by an authoritative source claims that it is "larger than seventeen of the biggest eagles put together". It has a strong black beak about wide and in length, the final of which taper like that of an eagle. The creature's neck is almost long with a girth of a little under . Short black powerful legs lead to webbed feet with gigantic claws. An imprint of a boobrie's foot left in some lakeside mud equalled "the span of a large wide-spreading pair of red deer's horns". It bellows noisily with displeasure, sounding more like a bull than a bird. The design of its wings is more conducive to swimming rather than for flight. Its evil powers when in the form of a bird were said by Campbell of Islay to have "terrified a minister out of his propriety". The boobrie's insatiable appetite for livestock posed a threat to local farmers, as they relied on their animals as a means of providing income and food. Although sea lochs are the boobries' natural home they will shelter on land in overgrown heather. Accounts are inconsistent as to the extent of the boobrie's habitat. Campbell of Islay claims that it is specific to the lochs of Argyllshire, as does Emeritus Professor of English James MacKillop. The writers Katharine Briggs and Patricia Monaghan on the other hand consider the creature's range to be the broader Scottish Highlands, although Briggs does sometimes specify Argyllshire. Campbell of Islay's undated manuscript notes the boobrie had not been seen for several years probably due to the widespread burning of heather in the area of its habitat. When manifested as a water horse the creature is able to gallop across the surface of lochs; the beating noise of the creature's hooves on the water is the same as if it were galloping on solid ground. Henderson reproduced parts of Campbell of Islay's manuscripts when writing "Survivals in belief among the Celts" (1911). Among them is a story listed as "boobrie as tarbh uisge". The tale starts by detailing how a man named Eachann fed a colossal black bull when he discovered it writhing in pain and possibly close to death at the side of Loch nan Dobhran, on the west coast of Argyll.