ize & Shape Pine Siskins are very small songbirds with sharp, pointed bills and short, notched tails. Their uniquely shaped bill is more slender than that of most finches. In flight, look for their forked tails and pointed wingtips. Color Pattern Pine siskins are brown and very streaky birds with subtle yellow edgings on wings and tails. Flashes of yellow can erupt as they take flight, flutter at branch tips, or display during mating.