William Beebe,
The Log of the Sun: A Chronicle of Nature's Year
“ One evening we notice the juncos and tree sparrows in the tangled, frost-burned stubble, and the next day, although our eye catches glints of white from sparrow tails, it is from vesper finches, not from juncos, and the weed spray which a few hours before bent beneath a white-throat’s weight, now vibrates with the energy which a field sparrow puts into his song. Field and chipping sparrows, which now come in numbers, are somewhat alike, but by their beaks and songs you may know them. ”
