I am not well adapted to northern winters. Let’s get that out of the way right now. Driving to work through freezing darkness is just a prelude to a frigid day with lead gray skies and biting wind. What’s the point? I run the heater at full blast and play tropical music to put my mind someplace else. It’s pure denial and that’s the way I roll in January. The way I see it, sunrise is supposed to be a biological explosion. All the night creatures are going to bed, the day’s birds and insects are awakening, and when all these living things cross paths they stake out their turf with hoots, roars, tweets, chatter, and flutelike songs. Nowhere is this more true than in a tropical forest. An hour before sunrise the heat of the day starts to burn off the coolness of the night and the birds and forest animals go bonkers. What’s even better about this is that every animal has a specific time that it makes a racket, some predetermined time of X minutes before sunrise, and the chorus is so precise that I can actually tell time by which animal I am hearing. One day in April in a lowland rain forest in Central America I recorded the sequence of a dawn chorus:
04:11 – Great Tinamou
04:20 – Collared Forest Falcon, Mottled Owl
04:21 – Brown Jays
04:25 – Laughing Falcon
04:36 – Thicket Antpitta
04:40 – unknown woodcreeper
04:46 – Uniform Crake
05:05 – Keel-billed Motmot and Rufous Motmot
05:13 – Ivory-billed Woodcreeper
05:18 – Red-crowned Ant-Tanager, unknown whinny
05:20 – Black-faced Antthrush
05:25 – Long-tailed Hermit
05:30 – “All hell breaks loose”
The pattern repeats every morning. Depending on how far I need to walk for work I know what time to get out of bed by the animal I hear calling. “Uh-oh. It’s the Laughing Falcon – time to get going.” Or “Half past Black-faced Antthrush already? Dang! How’d I oversleep?”
And THIS my friends is how sunrise is supposed to work. Just one of a thousand lessons learned in the ultimate school for biology: a tropical rain forest.
Come back soon for an upcoming blog “Dawn Chorus II” where we’ll discuss the biology behind the dawn chorus and how these birds know what time it is.
More about birds
To learn about any of the birds listed above and see their photos, visit Neotropical Birds by Cornell University. To listen to birds from all over the world, visit Xeno-canto.
Links to “Tropical Music” – Click on the links and set your mind free
good stuff
Dawn choruses of birds in the tropics provide an example of communication in the presence of high levels of heterospecific background noise. The combination of high species diversity and a narrow window of time in which the majority of species sing should increase possibilities for acoustic interference and limit possibilities for song divergence. Beyond the basic species specificity of their songs, we know little about how these songs are distributed in acoustic space and perceived in noisy acoustic environments.