You head to work early; it’s still dark and cold. It’s too dark and cold to make a logical reason to be up, and already you can hear them – those crazy birds aren’t just awake, they’re already whooping it up with their trills, melodies and crescendos. You are witnessing what is often called the “dawn chorus” – that period of time before the sun shows itself, but when the great outdoors is already filled with beautiful sounds of nature. The birds that you hear are mainly males. They are doing what male birds do best, protecting/claiming their territory and/or trying to attract a mate.
There are a few theories about why birds sing so vigorously during those per-light hours. For many years, the prevailing theory was that those early hours are typically the coolest and driest hours of the day which allowed bird songs to travel the farthest, giving their voices better range. It’s sending a message to other males that they should stay away…and the farther away the better. It was also assumed that females could be attracted from farther distances.
In the 1990’s, scientists discovered that this theory had some holes in it. When they studied the range of two sparrow species who participate in the dawn chorus, they found that their songs traveled just as far, if not farther, at noon as in the pre-daylight hours. They conducted their studies on both woodland and grassland sparrow species and found that their results were the same. They found that the individual bird’s songs were more consistent and clear in those pre-dawn hours than at any other time of day, primarily due to lack of wind. So, if you are a male bird trying to attract a mate or stake out your claim to a territory, it’s more important to make sure that your fellow feathered friends or foes know that it’s you singing away than it is to be heard over a long distance.
A completely different theory is that “early bird” singing has little to do with the effects of heat, humidity or wind but has everything to do with proving how strong male birds are. The way to impress the females and to scare away your competition, in the bird world, is to be big, strong and vigorous. It is thought that the better you can sing during the most challenging time of the day, the better mate and more challenging competitor you will be. So, if you can sing loud and strong in the early morning, before you have time to warm up and have a good hearty breakfast, the better mate and stronger defender of your territory you will be.
Both theories seem to make sense to me, and I think that a combination of both theories is the genesis of the dawn chorus. In any event, the reason behind the “why” becomes less important to me each and every time I get the privilege and honor of hearing this mysterious, beautiful and wonderful event. I encourage you to set your alarm early this spring, and go outside to experience one of the finest wonders of nature.