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Around this time of the year, we will begin to see the early arrivals of some of our songbirds. I have already seen a few robins and red-winged blackbirds. These early arrivals are all adult males. The females and juvenile males will arrive in about ten days to two weeks.
After the female birds arrive, the mating season will begin. At this time, we will be treated to the enjoyable sounds of birds singing. There are two kinds of bird vocalizations, and they are songs and calls. Bird calls are generally brief and are made by both males and females.
These calls are used to communicate with the feeding flock; rally their young or warn of danger. Warning calls are not only heeded by birds of the same species but other species as well. Even mammals have learned to recognize a bird’s warning call.
Many a deer has been warned of a hunter’s presence by a bird’s call.
A bird’s song, which is a series of notes in a recognizable pattern, is given mostly by the male as part of his courtship activity. However, the female cardinal is an accomplished singer, and her song cannot be distinguished from that of the male.
Birds sing primarily in the morning and evening, with very little done during the middle of the day. Most birds will respond (counter-sing) to another bird’s song at any time. We do have some night singers, such as owls and whip-poor-wills that sing occasionally during the mating season. The male mockingbirds sing all night long.
The amount of time a bird devotes to singing indicates the importance of song to their lives. At the height of the breeding season, one song sparrow was heard singing for nine hours during a 24-hour period.
At first, the songs of the males are territorial, a warning to other males that the area is already claimed. After the females arrive, the males will augment their songs with higher pitched notes to attract the females.
While singing, the male bird will spread his wings to make himself look bigger and more appealing to the females. It’s important for the female to pick a good mate because, in most cases, her offspring will live or die depending on the male and his ability to fight off danger and find food.
One of the most important decisions we humans make is when selecting our mates, and this is also true with our feathered friends.
Not all birds have a pretty sounding song. The red-winged blackbird has a loud conk-a-ree, and the starling has high pitched squeaks, whistles, and chattering. There are also birds that have lovely sounding songs. For example, the Hermit Thrush has one of the most beautiful songs heard in North America.
The book entitled “The Nature of Birds” by Adrian Forsyth states, “He starts out with a low, extended tone that flows out pure and liquid and then dances up flute-like and twists into a delicate phrase. After a pause, he begins again, sometimes with a variation in pitch but always following the same pattern, a pentatonic scale (a five-tone scale, omitting the fourth and seven tones) like that used in much of our ancient human music.”
Walt Whitman wrote this about the Hermit Thrush’s song:
From the deep secluded recesses,
From the fragrant cedars and the ghostly pines so still,
Came the carol of the bird.
And the charm of the carol rapt me,
As I held as if by their hands my comrades in the night,
And the voice of my spirit tallied the song of the bird.
I must confess that I have a problem identifying birds other than the most common by their calls or songs. The songs of the chickadee and cardinal are my favorite. Each year I try to learn bird calls; however, I am happy to be able to identify them by sight without opening my bird book. I find that the older I get the more difficult this becomes my memory is not what it used to be.
Why do bird species have different sounding songs? Why are some sharp and shrill, while others sound like a melody? Some naturalists feel it is to prevent attraction of the wrong species and avoid hybridization, while others feel the call relates the bird's age, size, and vigor to its mate and rivals.
It has been proven that the songs of polygamous species are relatively noisy. They use a greater range of frequencies, with many more buzzes, clicks, booms and slurs than monogamous species. The monogamous species are more musical and rely on whistles and phrases of relatively pure tones.
Some biologists feel that the songs of polygamous males are aggressive signals related to dominant interaction at mating sites. A male that can create an aggressive vocal display will usually attract the most females.
Scientists have found that for a bird to produce a loud-low pitched sound, a large vocal apparatus is required, one that is larger than it does for a higher-pitched sound, which means that the bird is older than other birds. Since size usually determines a bird’s fighting success, a bird will avoid a fight with another bird that is able to produce a louder lower-pitched noise than it can produce itself.
This can be related to the sounds that a dog makes. Do not try to pet a dog that is giving off a low-loud growl, which can easily be recognized as a sound of aggression; however, a dog that is giving off a high-pitched whimper indicates a sound of submission.
I don’t need to tell you about the dawn chorus of birds. We have been told that these choruses are the males alerting other males that they have their territory staked out. We are also told that a bird can lose up to 5% of its body weight during the night. If this is true, one would think the first thing a bird would want to do in the morning is to find food and not sing.
Some biologists have suggested the reason for their singing is because at dawn the air turbulence is lower, and the bird’s song is carried more effectively. Others have argued that only males in good condition can afford to sing at dawn and are advertising their quality.
Perhaps, we will never be able to fully understand the differences in the birds’ songs. I do know that awakening on a summer’s morning would not be the same without hearing their songs.