The sun has once again crossed the equator, heading north to warm the hemisphere it has neglected the last six months. That crossing, of course, is the official start of spring–the season of renewal. Here in Alberta it can be difficult to see any signs of warming in March. Although the days are getting longer (at Edmonton’s latitude, sunlight increases by about four minutes each day on average), the temperature is usually at just above or just below freezing, with occasional jumps into the double digits (on the Celsius scale) at both the high and low ends. Even today, the 5th day of April, it is snowing heavily outside my window with a temperature of about -5 C and high predicted to be -1.
So other than day length, how do we know spring is here? Well, other than relying on the calendar and the promises of the weather person on TV, you have to look to nature. My earliest sign of spring comes from one of my favorite animals, the red squirrel. We have a lot of them around our place and during the winter they make regular stops at our bird feeders. Now, others often consider these animals to be pests and discourage them from getting onto their bird feeders by elaborate shields and contraptions. We gave up doing that after we discovered how far a squirrel would go to beat whatever contrivance we could come up with.
How do these squirrels know it’s spring? Because their bodies tell them so. The first signs we see are the chases through the trees. These usually start in early March and involve mostly males. Now, when the males at this time of year arrive at our bird feeders it is easy to distinguish them from the females. The males’ testes are hanging between their hind legs in furry scrotums. They are an impressive sight, easily being ten percent or more of the body weight of the animal.
The battles between the males continue until one of the females in the area comes into season or ‘heat’. She emits a pheromone that instantly telegraphs to the males in the area that she is receptive. Then the chases become mobs, as all the males in the area chase the receptive female about the forest. These are violent affairs as males often fight each other and sometimes the female for the right to mate with her. She may mate with one or more of them. She is only receptive for a few days and soon returns to her territory and drives all males from it. The males then move on to the next female who is ready for a chase.
Now, these animals are normally very territorial but during these battles, territorial boundaries disappear. When the breeding season is over, usually by early April, each individual sets up his or her territorial boundary again and repels all intruders. [For more information about red squirrels, read my article posted on my web site.]
The dropping of the testes and the chases through the trees is just one of the ways nature demonstrates her faith that spring is indeed on its way. Changes in day length trigger many of these events, but they are still wondrous sights to behold.
So, what?s wrong with that?