FEMALE CHOICE FOR MALE MORPHOLOGICAL TRAITS IN-HOUSE SPARROWS, PASSER-DOMESTICUS

Female mate choice for male morphological traits was examined in capti ve house sparrows in New Mexico, USA. A study of house sparrows in Den mark indicated that male bib size is important in female choice (MOLLE R 1988, 1989). To examine this issue further, and to compare the selec tive pressures on male morphological traits between the two population s, bibs of males were manipulated to one of four standard sizes and fe males were allowed to choose from four males, one of each bib size. Th e amount of time the female spent with each male was recorded for 40 t rials. Males were then ranked in each trial, with a rank of 4 given to the male the female spent the most time with. The ranks a male obtain ed were then averaged to provide an indication of a male's attractiven ess to females. Data from 23 different males indicated that bib size w as not correlated with a male's average rank, even when the effects of other traits were controlled statistically. In addition, the size of the original (unaltered) bib was not correlated with male average rank . Bill depth was the only trait significantly correlated with a male's average rank. Differences in the populations studied or the methodolo gies used may have led to differences between the results obtained in this study and that of MOLLER (1988).