I was thinking if the Kig-yar were anything like the birds on earth then it would make sense if the females and males would look different. And it is said so in the halopedia:
"The female of the species lack the spiny plumage (said plumage's color serving as indication of the Jackal's mood) of the male; replacing it with calloused plates at the forearms and the rear of the head."
So this got me thinking what if the males of the species are, as we call them Skirmishers, and the females are actually Jackals? This would make sense however there it is said somewhat other wise:
"Aside from the obvious differences in reproductive organs, the male and female of the species are more or less identical in appearance with no physical disparity or mass distribution between the sexes."
However even if all males (in this case saying they were Skirmishers) it would be possible for their race to survive, as Halopedia puts it:
"When mating, the male can choose to fertilize the egg, in which a male is produced, whereas if the eggs are not fertilized a female is produced."
So that is my hypothesis,what do you think?