If I have said it once I have said it a million times. Nature is dynamic and is always changing. Nature does not stay the same nor does it do the same thing year to year. This winter is a perfect example of nature at its most dynamic. It would appear that despite the fact that the upper Midwest is having a “real” winter with near record amounts of snowfall and bitter cold, a sizable amount of American Robins and Eastern Bluebirds have not migrated and are spending the winter right here.

I have had at least a dozen phone calls and many more emails from people with robins or bluebirds or both visiting their yards this winter. Each caller is first surprised and then concerned that the birds won’t make it and want to know what they can feed these non-migrators. It is at this point that I go into my short speech about the dynamics of nature. So here it goes again.

Starting back in the middle 1800’s Charles Darwin wrote about how nature is always changing and is never the same. This was the basis for his theory of evolution. Well, here we are over 150 years later and I think we are comfortable in saying that Darwin was correct. Nature is dynamic and changes. Without change I am not sure any species could survive.

Naturalist like myself who study birds and animal can tell you that the population of a species is always changing. Some years the population is high while in others it’s low. Lemmings are a good example of this. The weather, food, disease and reproduction all play a huge roll in the population of these critters. Some animals such as the Ruffed Grouse and the Snowshoe Hare are on ten year population cycles. Animals that prey upon these critters such as the Northern Goshawk and the Canada Lynx are also on the same ten year cycle but lag behind their prey base by one or two years. It is really a boom and bust cycle.

Not only does a population change in nature, it also changes in behavior. And this is where the American Robins and Eastern Bluebirds come into the story. Some years a small percentage of the population doesn’t migrate. Those that don’t leave will eke out a living eating fruit and berries left over from last summer. Finding a source of open water is also very important. Usually these birds seek shelter in low areas such as along a river or creek valleys. 

Not migrating might seem like a crazy idea for a robin or bluebird but if they can pull it off it can pay off big time. Not migration seems dangerous, but it’s really no less dangerous than migration because migrating can be very dangerous. There are many perils to face during migration, such as finding food in a place you have never been before. Or avoiding predators or storms. Flying into power lines or tall buildings. And the list goes on and on. Migration is not easy and can be deadly.

Besides, the payoffs for not migration can be huge. Being the first bird back on the breeding grounds means you have first choice of the territories and the nesting areas. Every study shows that the first birds back get the best breeding territories and are the most successful at reproducing. After all, successful breeding is what nature is all about.

It’s our human nature to ask and wonder why and the answer is simple—nature is always changing and is dynamic. This is the basis for why nature is so successful. It is always trying something new or exploring new avenues or niches. Until next time…