It’s spring and many of us are waking up to beautiful bird song. But have you ever stopped to think about why birds sing in the early morning?
What is the Dawn Chorus?
Scientists are still investigating the mysteries of dawn choruses. Typically, birds begin singing 30 – 90 minutes before the sunrise. Different birds will chime in at different times. Blackbirds, robins, and thrushes are among the first to begin singing. Others will soon join them and this chorus will last until the sunrise fades. The brighter light signals that it’s time for the birds to go about their daily activities. The rest of the morning and afternoon will be relatively quiet with a few songs interspersed throughout the day.
To the untrained ear, the dawn chorus can sound like beautiful chaos. But, to birders, scientists, and careful listeners, this chorus can reveal a lot about the birds in the area, including their health and their environment. You too can begin to decipher these beautiful songs with a little research, attention, and persistence. A good way to go about this is by choosing a sit-spot for daily observation.
Why Do Birds Sing in the Early Morning?
Scientists have a few different theories to explain why birds sing at dawn. Some studies have shown that dawn singing is a way for birds to resolve social dynamics. This includes what territory belongs to who.
Singing can actually be a sign of aggression. One study looked at dawn singing in banded wrens in Costa Rica. Researchers found that males would direct their morning songs at their
Scientists also believe that morning singing could be a way to display strength and health to potential mates. Support for this theory lies in the fact that the chorus is most vibrant during the mating season. It is also led primarily by male birds.
As to why singing happens in the morning and not later in the day, many hypothesized that there was less atmospheric turbulence in the morning allowing bird song to reach longer distances. But, recent studies have shown that bird song travels as far in the afternoon as in the morning. Even so, morning songs are less likely to be interrupted and may be crisper.
A study published in the Journal of Behavioural Ecology looked at how birds near airports timed their morning songs so as to minimize the competition with air traffic. Also, its long been understood that city birds will modify their songs to increase their reach in noisy areas.
Pollution and Bird Song
Another interesting finding was published in the Journal of Oecologia. The study “compared the singing
So, the strength and vibrancy of the dawn chorus may be
After the Dawn Chorus
Birds may begin singing pre-dawn because there is not enough daylight to successfully forage and accomplish other daily tasks. After the dawn chorus, birds have to get back to their daily routine. Young writes, “assuming no immediate predatory threats and alarms, the specifics of this [morning activity varies] with the ecology of a given habitat; the season; the temperature and other weather conditions, such as wind, fog, and humidity; impending weather…” and other factors. In the springtime, this activity will usually involve some amount of foraging, patrolling borders, and singing together in courtship.
John Burt and Sandra Vehrencamp. 2005. “Dawn Chorus as an Interactive Communication Network” in Animal Communication Networks edited by P.K. McGregor.
Timothy Brown and Paul Handford. 2002. “Why Birds Sing at Dawn: The Role of Consistent Song Transmission” in International Journal of Avian Science.
Diego Gil, Mariam Honarmand, Javier Pascual, Eneider Pérez-Mena, Constantino Marcías Garcia. 2015. “Birds Living Near Airports Advance their Dawn Chorus and Reduce Overlap with Aircraft Noise” in Behavioural Ecology.
Gorissen, Snoeijs, Duyse, and
Jon Young. 2012. What the Robin Knows: How Birds Reveal the Secrets of the Natural World.