A Field Technique for Bursal Inspection of Mourning doves

Abstract

fully adult birds is referred to in this paper as young-adult. We call the other group full-adult. These age classes are readily separated in both species by differences in color and pattern of the upper primary coverts. Our data show the sexes in the two age classes to be distributed as follows: Gambel's quail: young-adult, 105.9 males per 100 females (270: 255); full-adult, 126.3 males per 100 females (120: 95). Scaled quail: young-adult, 90.2 males per 100 females (101: 112); full-adult, 143.1 males per 100 females (83: 58). We interpret these results to mean that, under natural conditions, a definite sex-differential mortality occurs, favoring males, in both Gambel's and scaled quail. Apparently, females do not fare as well as males in the struggle for survival. This probably accounts for the observed difference in relative numbers of males and females in the wild, although our data do not absolutely rule out the possibility of an original difference. The anomalous sex ratio noted for young-adult scaled quail almost certainly resulted from errors in sexing the birds. Live scaled quail are routinely sexed on the basis of slight differences in the color of the throat feathers. Ideally, in males these feathers are clear buffy, while in females they are grayish with faint longitudinal brown streakings. In full-adults these differences are usually very evident to a practiced eye. In young-adults, however, they are less definite and more variable, tending in general toward the female condition. This no doubt causes many errors in sexing scaled quail of this age class. That it is possible, nevertheless, to sex this species accurately by the method mentioned is indicated by the fact that one of the authors, after he had acquired several years experience sexing scaled quail, sexed a test series of 17 live birds without a mistake, as subsequently confirmed by dissection. Eleven of these were young-adults. Due to obvious differences between males and females in Gambel's quail of all ages except quite young birds, this species can be accurately sexed. Accepted for publication August 26, 1954.