The night sky was moonless with between and of visibility. All of this sometimes took place in moonless, 24-hour Arctic darkness, December through February. The night was cloudy and moonless, and fog had set amidst the remaining PTs. They appear happy and carefree but fear the dark, and particularly moonless nights. Birds were taken from roosts in the trees during the moonless period each night. Some navigators mount a light-amplifying monocular to help see the horizon on moonless nights. They are nocturnal at the colonial breeding sites, preferring moonless nights to minimise predation. They are nocturnal at the colonial breeding sites, preferring moonless nights to minimize predation. Water fowl were captured on moonless nights using strategic flares. It is caught using light attraction during moonless nights. After a few miles, the plane flew into the ocean on a moonless night. This led to increased illumination in low ambient-light environments, such as moonless nights. They were operated independently on moonless clear nights. Black-water diving is mid-water diving at night, particularly on a moonless night. The Ottoman destroyer sortied late on 12 May under cover of a moonless night.