He constructed plaster eggs to see which a bird preferred to sit on , finding that they would select those that were larger , had more defined markings , or more saturated color-and a dayglo-bright one with black polka dots would be selected over the bird 's own pale , dappled eggs .
He constructed plaster eggs to see which a bird preferred to sit on , finding that they would select those that were larger , had more defined markings , or more saturated colour-and a dayglo-bright one with black polkadots would be selected over the bird 's own pale , dappled eggs .