If you've been confused by the birds begging for Silky and Smooth at the beginning of Dark Souls II, leave them a silky and smooth stone and they will give you a random item in return.
If you leave the birds the following items, you have a chance to get:
1) Petrified Something (Starting Gift) - Demon's Great Hammer, Channeler's Trident, Old Whip, White Ring, Titanite Slab, or Petrified Dragon Bone.
2) Prism Stone - Small Blue Burr, Small Orange Burr, Small Yellow Burr, Fading Soul, Homeward Bone, Rubbish
3) Small Smooth and Silky Stone - Lifegem, Cracked Red Eye Orb, Cracked Blue Eye Orb, Soul of a Lost Undead, Soul of a Proud Knight, Titanite Shard, Titanite Chunk, Titanite Slab
4) Smooth and Silky Stone - Amber Herb, Human Effigy, Divine Blessing, Crimson Water, Boltstone, Magic Stone, Firedrake Stone, Poison Stone, Bleed Stone, Darknight Stone, Raw Stone, Faintstone, Old Mundane Stone, Twinkling Titanite