However, the largest bodied race of barn owl, "T. a. furcata" from Cuba and Jamaica, is also an island race, albeit being found on more sizeable islands with larger prey and few larger owls competing for dietary resources. The shape of the tail is a means of distinguishing the barn owl from typical owls when seen in the air. Other distinguishing features are the undulating flight pattern and the dangling, feathered legs. The pale face with its heart shape and black eyes give the flying bird a distinctive appearance, like a flat mask with oversized, oblique black eye-slits, the ridge of feathers above the beak somewhat resembling a nose. The bird's head and upper body typically vary between pale brown and some shade of grey (especially on the forehead and back) in most subspecies. Some are purer, richer brown instead, and all have fine black-and-white speckles except on the remiges and rectrices (main wing and tail feathers), which are light brown with darker bands. The heart-shaped face is usually bright white, but in some subspecies it is brown. The left ear is slightly above the eyes on the vertical plane, whereas the right ear is slightly below the eyes. The orientation of the ear coverts in relation to the face also differs between the ears, with a difference of about 15°. The underparts, including the tarsometatarsal (lower leg) feathers, vary from white to reddish buff among the subspecies, and are either mostly unpatterned or bear a varying number of tiny blackish-brown speckles. It has been found that at least in the continental European populations, females with more spotting are healthier than plainer birds. This does not hold true for European males by contrast, where the spotting varies according to subspecies. The beak varies from pale horn to dark buff, corresponding to the general plumage hue, and the iris is blackish brown. The feet, like the beak, vary in colour, ranging from pink to dark pinkish-grey and the talons are black. On average within any one population, males tend to have fewer spots on the underside and are paler in colour than females. The latter are also larger with a strong female "T. alba" of a large subspecies weighing over 550 g (19.4 oz), while males are typically about 10% lighter. Nestlings are covered in white down, but the heart-shaped facial disk becomes visible soon after hatching.