Thanks guys for clearing up what I left unclear. As stated, you can can only hunt either sex or buck deer/elk in one season for each species. But, you could hunt a buck in one season, a bull in another season, and get a cow/antlerless tagthat as an "additional" tag in another season inaddition to the other two tags.

What you really need to do is click on the link provided above (Colorado DOW) and read through it. It will answer most of your questions.