Friday, April 27, 2007

Be a bird brain

Express Staff Writer

Is spring early or late this year? Due to the lack of snow, at first it seemed to be on the early side, but a year ago everything in and around my garden was much hardier due to the big snow year and the soggy ground. Lack of snowmelt means that mud season is barely discernible. Sure, trees are budding, and tulips and daffodils are up in some places but perhaps we should look to the sky for the real answers.

Birds are a fairly good way to gauge the successions of the seasons. Are the birds on their way or have they already arrived? The study of these passages—be they plants or birds—from year to year is called phenology. This refers to the indications, year after year of the coming of a season by dating the of emergence of leaves and flowers, the first flight of butterflies and the first appearance of migratory birds among other phenom-ena.

So, despite the unusually lousy snowfall in South Central Idaho this winter, the birds are "right on schedule," said local birder Brain Sturges.

"These birds are coming from Mexico and South America. They don't know what the weather is like here. Nothing has been spotted earlier than any other year. The red-wing blackbirds come each year the sec-ond week of February, and they were here on the sec-ond week of February."

Sturges explained that bird migrations flow in "leaps and bounds. They leap up here and if the weather is good, they'll move on. If it's lousy, they'll stick around."

Sturges added that no tanagers or hummingbirds have been spotted yet at this altitude but should be ar-riving by next week.

"The nesting success will be dependent on water and food supply. That will be more critical, but we won't know that until June, July and August. If there's not enough food, they may only nest once versus two or three times," he said.

The food supply the birds are dependent upon is itself dependent on the snow runoff, which will be lim-ited this year. Emerging plants provide food sources for many animals, which in turn are food sources for certain predators. Warmer temperatures, which urge these plants to grow, bring on pesky insects that are themselves the essential diet for numerous bird spe-cies.

As a gardening exercise it can be helpful to plot your own landscape's pheonology from year to year. A general rule of thumb is that spring advances about one week for every 100 miles of latitude. If you go 100 miles north, plants should be about one week behind in flowering. Similar patterns of "new life" occur with increases in elevation of mountainous terrain. So, the spring wildflowers soon to be blooming in the Wood River Valley, won't appear in the Sawtooth Valley un-til early summer.

So look at the ground for insects and look to the sky for migrating birds to know how successful the coming season will ultimately be. The knowledge you gain can make a difference in terms of your upcoming landscap-ing and gardening plans.

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