Now scientists at Deakin University in Australia have discovered that in zebra finches what the eggs hear and how they respond is even more amazing than we knew.
In the last days of incubation, zebra finches (Taeniopygia guttata) sing a special song to their eggs but only when it’s hot outside — greater than 26 degrees C (78.8 degrees F).
The eggs hear the song and it changes their lives.
After they hatch, babies who heard the “hot call” grow more slowly than those who didn’t. Not only are the “hot call” babies smaller as adults but they’re more successful breeders in a hot climate. Surprisingly, this effect extends into later generations.
Small bodies cope better with heat than large ones, so signalling for a smaller size is a great adaptation for a warming climate.
But how does the zebra finch song bring about this result?
Click here to watch the video and read about this amazing feat.
(screenshot from Science Magazine video about zebra finch vocalization. Click on the screenshot to see the video)
This 3-note song mystified me in my own backyard. I can usually identify birds by ear but this one stumped me for at least six weeks.
Finally, I recorded it outside my window and sent it to my friend Dr. Tony Bledsoe. Tony suggested a tufted titmouse. (Turn up your speakers to hear the song in the video above. Ignore the picture, the bird’s not in it.)
A few days later I saw the bird. No wonder we didn’t recognize the song! He’s a gray catbird that sounds nothing like his cohorts. (Turn your speakers back down for the audio below.)
Most birds are silent in early July but the odd-sounding gray catbird is still singing in my neighborhood and I can guess why.
None of the lady catbirds like his song so he’s still calling for a mate.
American robin, skygazing (photo by Joel Kluger on Flickr, Creative Commons license)
Songbirds are well aware that birds of prey will eat them so they warn each other when they see one. Their warning calls can alert us, too, that a predator is circling overhead.
American robins (Turdus migratorius) stand very still, turn one eye to the sky(*) and make a very thin, high-pitched sound similar to a cedar waxwing’s call. Seet. On the sonogram below it’s shaped like an eyebrow. Here’s what it sounds like:
European starlings (Sturnus vulgaris) make a spitting sound that’s much easier to hear.
European starling (photo by Chuck Tague)
They sound off from a safe perch or call “Danger! Danger!” as they take off to avoid the predator. In my experience, they only use this sound when they see danger in the sky. Here’s what it sounds like:
When you hear these calls, look up to find the hawk. At Schenley Plaza it may be a peregrine falcon.
(*) American robins turn one eye to the sky because they don’t see straight ahead as well as they do side to side. For more information see Anatomy: Field of View.
Now every morning we awake to birdsong. All the singers are male, right? Well … not really.
When I took a class on birdsong years ago I learned that female birds don’t sing. This information came from centuries of bird observations made in Europe and North America. Charles Darwin even used it to describe how song evolved in male birds to attract mates and compete for territory.
Superb lyrebirds (Menura novaehollandiae) are the size of pheasants and native to southeastern Australia. The males are famous for their courtship displays which include shaking their elaborate tails and accurately mimicking a wide variety of sounds.
In the wild, superb lyrebirds mimic natural sounds. In 2009 there was a lot of construction at Adelaide Zoo. When the breeding season came Chook faithfully reproduced the sounds of hammers, power drills and workmen whistling on the job.
Close your eyes at the 3:15 mark and listen to the handsaw!
Every year my husband and I spend a relaxing two weeks at Acadia National Park where we enjoy spectacular scenery, wildlife, and hiking trails. Now that we’re heading home I’ll share some of the highlights. The best is a sound that I will certainly miss in Pittsburgh — the haunting call of the loon (Gavia immer).
In September common loons migrate through Canada and Maine from interior lakes to the sea. Each one migrates alone, independent of its mate and offspring.
One particular loon, distinctive because he was molting into winter plumage, often spent his evenings at the harbor. Every morning I heard him make the tremolo call at dawn (click here to hear) but last Wednesday, when the fog came up just after rain, he made a haunting wail call that echoed among the mountains.
Watch the video above to learn what the wail means.
October is sparrow time in Pennsylvania. Migrating warblers have left. Migrating sparrows have arrived.
Though swamp sparrows aren’t singing right now, the species is famous for their regional dialects. Over the winter they’ll be exposed to other sparrows with other dialects. Will they change their accents to match their winter friends or retain their dialects to use next spring?
The call is a warning. Goldfinches use it near the nest when there’s a dangerous predator nearby. Last Saturday I heard it repeated loudly for an hour while an immature Coopers hawk perched in my neighbor’s spruce tree. As soon as the hawk left the goldfinches stopped saying it.
Listen for the call and you’ll learn two things:
There’s a goldfinch nest nearby and …
There’s also a hawk, cat or other danger in the vicinity.