Tuesday, August 11, 2009
A couple of days ago I was able to get out as the sun was setting and I headed to the bison pasture to see if they were near the fence in the warm light. There are two mature bulls in the pasture and they were off by themselves near the fence.
I wasn't sure if there was some animosity between the two bulls in the short time I was watching them but there seemed to be a bit of tension between the two.
This bull exhibited a Flehmen response, probably a reaction to the scent of the urine of one of the other animals. This response is thought to help expose the vomeronasal organ, a chemoreceptor organ mainly used to detect pheremones, to the scent molecules.
The bison were attended by Brown-headed Cowbirds.
It was nice to see the cowbirds feeding on insects flushed by the feeding bison, a role they had occupied for millennia. I was able forget for a moment their more recent role as a avian parahia, leaving their eggs in other birds nests for the host species to raise, a behavior well adapted to following ever moving bison herds, but trouble for novel host species as cowbirds expanded beyond the short grass prairies and replaced their association with the ever moving bison with more widely distributed and more sedentary domestic livestock.
It was a glimpse back in time that could have occured thousands of years ago in exactly the same place.
Posted by John Carlson at 8:08 PM