MALE FINCHES SELECTIVELY PAIR WITH FECUND FEMALES

Much attention has recently been focused on the factors determining ma ting success in animals. Most emphasis has been on variation in male c haracteristics, as females are often assumed to be the choosier sex. H owever, in monogamous species, securing a mate with high reproductive potential is important to both sexes. Here we show by means of manipul ation experiments that male zebra finches selectively pair with female s that, because of previous exposure to a high quality diet, will lay large clutches. This is the first demonstration that a female's probab ility of obtaining a mate is directly linked to her egg production cap acity independent of her age, experience or body size.