November Twenty-eighth
On returning to the nest and discovering that a cowbird has laid an egg in it, some species of birds will roll the egg out. But the phœbe, red-eyed vireo, chipping sparrow, and yellow warbler will sometimes cover the eggs with nesting material and build up the sides of the nest, thus burying its own and the cowbird's egg. Another set of eggs is then laid and the bird begins to sit, but the buried eggs are too deep to be affected by the warmth of the parent's body, so the "lazy-bird's" purpose is defeated.