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Come back to this page each day to read another entry from Cathie Katz's beautifully illustrated journal, "Nature a Day at a Time."
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Rock doves (Columba livia), our domestic pigeons, are grain eaters, built to pick up and digest the seeds and grains that fall on tree-lined sidewalks, people-filled parks, fields, backyards, and empty lots. Like the mourning dove, pigeons have a crop to store food at the end of the esophagus, so they can accumulate a lot of seeds at once without having to wait for digestion. When the stomach is ready, the crop releases the stored grain. Birds have two stomachs, one of which is the gizzard. Gizzards in birds do the grinding that teeth did in prehistoric birds. Why the change? To lighten the load for the air-borne animals, birds needed to eliminate the weight in their heads. Teeth were heavy, but without them, the problem of breaking up food remained. Hence the gizzard. The weight was redistributed to a more aerodynamically suitable position. And what about all those droppings? The laxative effect of plants allows the birds to discharge the seeds inside fruits rapidly. But why would the bird want to drop its load with such haste? It's not the bird, but the seed's tactic to get out before it loses its viability. Five or ten minutes can make the difference between survival and rotting away for a seed. The chemicals in the plants regulate the bird's movements- different time lapses for different birds.
We all consist of the same spirit of creation, although the terms of expression have changed; we now say we contain the same atomic matter as the rest of life, the same DNA as all life-forms."First People" by Linda Hogan in Intimate Nature |
Cathie Katz, the author of several books on natural history, also co-founded The Drifting Seed, an international newsletter about rain forest drift seeds. In her engaging Nature a Day at a Time, published by Sierra Club Books and Random House, Katz interweaves fascinating facts about familiar creatures, pen-and-ink drawings and quotations.
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