Tuesday, December 1, 2009

Ordinary Not

My blogs are not usually tied to any current events in the news, and this one is no exception. If you’ve come looking for the latest on Tiger Woods’s car crash or the elections in Honduras, you done taken a wrong turn. If, however, you find nature, and especially animals, to be an endless source of delight and surprise, read on.

This weekend provided two surprises, both of which are delightful in their different ways. The first involves fruit flies, the second house sparrows. Readers will note that these two species are among the most ordinary and routine among us. Ubiquitous in kitchens and parking lots, respectively, they rarely get a second glance. But, as a habitual animal-watcher, I’ve discovered that the rewards of watching and noticing are not linked to the rarity or grandeur of the object. On my playing field, a mouse is the equal of a lion, and a house sparrow no less deserving of my attention than a bald eagle.

The fruit flies were drawn like magnets to a half-peeled banana my daughter had left out. At any time of year, these tiny insects seem to materialize out of thin air. They also have an uncanny knack for getting at fruit, even fruit that is sequestered away. I once saw 100 fruit flies trapped inside a bowl containing a peach pit and sealed with a tightly stretched window of plastic wrap. Inquiring what it was for, my host explained that it was a fruit fly trap. She showed me the tiny holes she had poked in the window with the tip of a sharp knife. The flies, drawn to the alluring scent within, would find the holes, then push their way through the tiny apertures. The principle was like that of a lobster trap: relatively easy to get in, but virtually impossible to find one’s way out. Or so I thought. As I gazed at the trap, I was astonished to watch a fly walk across the translucent ceiling of his temporary living quarters, arrive at one of the tiny slots, then, using a front leg to gain initial access, squeezed his head through the slot and proceeded to wheedle his way through the crack to the outside. He paused briefly as if to reflect on his achievement, then he flew away. I didn’t expect that from a fly. I have since read of studies that show that fruit flies have an attention span. It makes me all the more pleased that I surreptitiously spared the fruit flies from the morgue in my genetics labs as a biology student, letting them instead recover from their ether fog to fly off into the room.

I thought I’d try the trap out at home. I peeled the remaining banana (sealing up a few other ripe ones in an air-tight plastic bag, to mute the competition), cut it in half, sealed it in a small bowl, then poked a dozen tiny slits with a knife tip. Four hours later, I counted about 15 flies inside, which I released onto the deck. This morning, another 20 flies found liberation on my rear deck. I didn’t notice any escaping through the exit holes, but I don’t doubt that they will if I wait to see. Meanwhile, there are now virtually no flies on the loose in my kitchen. This trap really works.

If you’ve watched house sparrows, you will have noticed that they have — like many birds — a quite nervous disposition. Chattery and active, they seem always on the alert for potential danger. They generally keep their distance from us, which seems a wise policy. The only ones I’ve gotten really close to have been either naïve fledglings with those tell-tale yellow corners to their beaks, or adults separated by a window, in which case they either know they are relatively safe, or more distracted by what is going on on their side of the pane.

Yesterday, as I went out to the deck to sweep leaves, there was a sudden commotion as a Cooper’s hawk flew by. These predators haunt the woods here, terrorizing the little birds that visit the feeders. When a Cooper’s swoops through (often catching a meal en route), it is usually an hour or so before any birds reappear at the feeders.

On this occasion, a red-bellied woodpecker flew squawking to a tree to my left, the hawk continued right, and four house sparrows remained inside my neighbor’s two thistle feeders. These feeders are surrounded by a cylindrical wire grid which allows entry to small birds but keeps out squirrels — and hawks. The sparrows seem to know this, for rather than fly off, they remained inside the baffles. The hawk, meanwhile, alit high in a nearby walnut tree, about 30 yards from the feeders and the sparrows they now protected. The sparrows were frozen stone-like in their spots. They didn’t move a feather. After a minute I quietly went back in and returned with my binoculars. For the next eight minutes, the hawk stayed at his perch, surveying his surroundings between bouts of preening. I also kept a close eye on the sparrows, who remained at their perches. Their stone-like stillness was uncanny. After five minutes, I began to detect the slightest movements to their heads, and some blinking. These were slow movements uncharacteristic for small birds. As far as I could tell, only one of the sparrows, a young male (judging by the sparse black feathers on his bib), had a direct line of sight to the hawk. But the big bird was not very prominent at the top of a tree 30 yards away; could they see him, I wondered?

I don’t know for certain the answer to that question, but I can tell you that within ten seconds of the hawk flying off over the townhouse rooftops, all four sparrows became palpably more animated — moving their heads about. Within 30 seconds, one of the females began taking seeds from the feeder hole that for the prior 8 minutes had been just beyond her face, but during which time she hadn’t budged. Five minutes later, only the male remained at his spot — the others had skidaddled.

There are many good scientific studies that attest to the cleverness and complexity of house sparrows, but for a wonderful layperson’s account, I recommend Providence of a Sparrow: Lessons from a life gone to the birds, by Chris Chester.


At December 9, 2009 at 8:47 PM , Blogger Beej said...

Dear Dr Balcombe,

I'm honored to have you visit my blog. Thank you for the praise for my blog and your tip to identify the moth.

Your blog and website are fascinating, and so are the subjects of your research. Are your books available in India?

Where have you traveled in India?

Bijoy Venugopal


At January 10, 2010 at 8:25 PM , Blogger Jonathan Balcombe said...

Dear Bijoy,

Sorry for slow reply, I only just discovered your comment now.

I first visited India in 1984 and traveled quite extensively...Mumbai, Lonavala, Goa, Kerala, Tamil Nadu, etc, and various memorable sanctuaries...Bandipur, Molem, Bharatpur (my favorite)...

I covered more terrain during a book promotional tour in January 2007. Email me at jonathan@jonathanbalcombe.com if you would like me to email you my travelogs from those journeys.

All best wishes,
Jonathan Balcombe


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