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Crafty ravens enlist cars as nutcrackers

A year or so ago, I was driving along an empty stretch of Old Olympic Highway when I saw a raven swoop down to the road surface. It then flew to the side as my car neared.

Seeing that it had left a large nut in the other lane, I was reminded of broken shells strewn in the parking lot at John Wayne Marina. There, gulls drop clams to break them open.

This raven was craftier. Somehow it knew that cars can crack open nuts. And it knew to carefully lay the nut on the pavement, rather than dropping it, only to watch it bounce away.

Rather than risk its life by laying the nut in the lane in which I was approaching, it demonstrated patience, knowing that cars eventually would travel in the other lane.

What it still had failed to grasp, however, was the role of tires in cracking a nut. The raven had left the nut in the middle of the lane, rather than in one of the two faintly visible tire tracks worn into the road.

Farsightedness in birds is intriguing, as illustrated by several examples.

One such activity is caching food, a trait common to many species of birds. A student in my Beginning Birds class once commented on finding peanuts in the shell on the ground in the woods near her house in the foothills.

I suggested Steller's jays as a likely source, as jays are known to cache food and they are large enough to carry peanuts. Local jays show a fondness for them, occasionally flying past with peanut shells clutched in their bills.

In Fort Davis, Texas, I saw the entire front of a wooden church, as well as a nearby telephone pole, riddled with holes. Acorn woodpeckers - one of my favorite birds, albeit not found locally - had drilled them to cache acorns in the holes.

Seemingly those acorns are much more easily found later than peanuts buried in a forest.

Pileated woodpeckers take a different farsighted approach to food gathering. They carve out rectangular holes (typically several inches wide and twice as high) in trees as feeding holes.

Particular target foods in these holes are carpenter ants and wood-boring beetles.

Bernd Heinrich, in his book "Ravens in Winter," relates personal observations of raven behavior. These birds are territorial, so that a downed deer or other large prey is essentially the property of the pair of ravens residing in that territory. Other ravens, presumably having spotted such prey during an overflight, recruit additional ravens from a communal night-time roost to dine on the prey the next day.

They succeed by significantly outnumbering the territorial pair and ultimately they all feed side by side, peacefully.

On a larger scale, some avian farsightedness - whether conscious or simply embedded in their genetic programming -- is reflected in life strategies.

In spring, males of many species, such as rufus hummingbirds, race ahead of the females to find and stake out the best breeding territories. Pressure on the male hummers to make wise choices is particularly high as they do not play any role in nesting and chick raising.

Capitalizing on the fact that birds, unlike mammals, don't nurse their young, a few species optimize the female role as egg layer.

Male and female phalaropes do an almost total reversal of gender roles compared to hummingbirds. Once a female phalarope has laid eggs, she leaves everything else to her mate, from incubating the eggs to raising the chicks.

Meanwhile she seeks a new mate to repeat the process. That's why female phalaropes, not the males, have the gaudy plumage - a rare phenomenon among birds.

Our resident song spar-rows have an unusual technique for getting along with each other in cramped quarters.

Song sparrows are numerous locally (as often elsewhere), and consequently males have small breeding territories. As related by Donald Kroudsma in "The Singing Life of Birds," male song sparrows - that typically develop unique songs - also learn the songs of their neighbors. And they learn which song belongs to which neighbor.

As a male patrols the perimeter of his territory, he will pause occasionally to sing the song of his immediately adjacent neighbor, seemingly an avian form of male bonding.

Think where mankind could be if nations adopted a similar strategy for dealing with neighboring countries.

My next Introduction to Birds and Birding class starts Tuesday evening, Sept. 22.



Author Dave Jackson is series coordinator and Web master. Send comments to him at editor@olybird.org or 683-1355. Archived articles and details of classes and trips are available at www.olybird.org.









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