Understand that zoologists, especially in the field, spend a lot of time very bored, and that's a recipe for making the dumbest dirtbaggiest jokes you can. What starts as "that bird looks like it's got a dick on its head dude" later becomes in scientific literature "phallocephalus"

If you've ever heard of the classic mating dynamic of "males who creep into the harem to mate while the alpha isn't looking," you have probably heard of them described as "sneaky males." This is a change from the original designation the field biologists who first studied this behavior gave it, "sneaky fuckers"