MYSTERY SURROUNDS HOW BIRDS COMMUNICATE

Saturday, September 22, 2007 

It isn’t too often that any of us pay much attention to starlings, except in devising ways to evict them from our nest boxes and feeders. However, during the fall season they are much more deserving of our attention as they gather in flocks and march across our lawns in search of insects. These huge flocks are made up of both adults and young of the year, possibly joined too by other individuals that have nested elsewhere in eastern Ontario.

Last week, about 300 or so gathered in the trees just west of our house. They were gathering in preparation to migrate, as most do in this area, despite those we may see at feeders in the winter. There was an extremely noisy conversational chatter going on among them that carried through the open patio door, overriding the program we were watching on TV. Interestingly, the program was a Discovery Channel presentation on migration.

Of course, at this time of the year, this singing has nothing to do with mate attraction, but is thought to be important for flock cohesion and establishing and maintaining social hierarchies within the flock. It’s a social thing and as each one struggles to be heard above its neighbour, the resulting cacophony of musical notes in a large flock is often so loud that normal conversation among humans in their vicinity is quite impossible.

Autumn is approaching, but we have seen this flocking before in other species earlier this year. It started in July with the early nesting tree swallows gathering in long ropes on the utility wires, preparatory to their journey south. Most of the local breeding tree swallows have now left, only to be replaced by successive flocks arriving and departing through this month. Still, we will see individuals and small groups lingering until November robs them of flying insects.

Back in my days of farming, I was always amazed at the dexterity of tree swallows as often hundreds of birds would zig zag back and forth in front of the combine, snatching insects disturbed by the harvesting operations. How they managed to keep their minds on their work without colliding in mid-air continues to be a mystery. We have seen this remarkable skill with shorebirds too at Presqu’ile, when thousands will take off together, wing tip to wing tip, then suddenly all banking together as though responding to a single impulse. We see it every winter too with snow buntings.

That birds communicate with each other is well known. We hear it in the dead of night as thrushes migrate overhead, single audible notes meaning nothing to us, but obviously something important to their neighbours in flight. But how birds can interpret, much less even hear these individual communication notes when flocks number many thousands and the noise is deafening, is not clearly understood. That they do it, and manage without error, is all that matters.

We witnessed another example of communication last weekend as a small party of kayakers crossed Newboro Lake, north of Chaffeys Locks. To escape windy conditions, we navigated through a number of channels between several islands not far from the village of Newboro, and suddenly found ourselves between two loons, each about 20 metres away. Loon voices vary, as all of us know, who listen to their haunting wails. These two were clearly upset with our sudden appearance and if it wasn’t so anthropomorphic to think so, it was as if we had suddenly flung a door open to their bedroom and had interrupted a tryst in progress. The individual to our left gave the familiar yodel, to signal its surprise, and its companion responded with a long wail, following it up with the seldom seen "loon dance," as the bird stood straight up in the water and violently slapped its wings. Both were clearly upset with our unannounced appearance and it was a strong signal for us to leave.

Birds flock and migrate by monitoring the Earth’s magnetic field with tiny grains of mineral in their heads called magnetite, and by actually following the stars. As stars and constellations change position in the night sky, somehow migrating birds are able to re-calibrate. They are experts in fuel efficiency and obviously have a sophisticated communication system when flocking together. Whoever came up with "bird brain" as a derogatory insult obviously had no knowledge of the inner workings of birds. When we call someone a "bird brain," we may, in fact, be paying the recipient a high compliment.