White-tailed bucks experience rising levels of testosterone in the fall and this leads to the rut, a gathering in November where bucks challenge one another for access to does.
I have not witnessed the head butting and mating of the rut, but this last week, I was fortune to be able to watch some pre-rut sparring. Three bucks were congenially grazing together in the rain. There were no does to be seen. Yet, their rising testosterone was urging them to spar and they did, after which they just returned to grazing.
These were a mismatched three. There was an adult buck with four-points on each antler, along with one-spike and two-spike yearlings. But, fitness is irrelevant when grazing.
The sparring started when the two-spike youngster challenged the one-spike youngster. The contest just fizzled.
Then the youngster challenged the adult. It was a clash with butting and head twisting, but the adult appeared to be gentle with his young challenger.
They went at it a couple of times, with the adult seemingly reluctant to put much effort into the contest.
“Well, what did you expect me to do? He’s a youngster.”