Sentence:  Underneath the big one , in the silent moonlight , lay a dead pigeon , and on the smaller bell , the Clemence , two gray and white birds slept huddled together in the cold <WSD>winter</WSD> air . 
Meaning of the word marked with <WSD> tags:  the coldest season of the year; in the northern hemisphere it extends from the winter solstice to the vernal equinox