Posts Tagged ‘Phenology’

Early March is a wonderful time in the central valley of California. It is becoming warmer, although this year it never really got that cold. A few rain showers bring welcome and much needed moisture to a region entering its fourth year of drought. The calla lilies are blooming and the first jasmine blossoms give the air the faintest hint of their wonderful, soft fragrance, a fragrance that will become much stronger over the course of the month. A few days ago, I saw my first Swainson’s Hawk of the year. These birds are just returning to the area after flying from as far a way as Argentina, and will be setting up their territories soon. Another first of spring that occurred a few days ago was my first Valley Carpenter Bee. It was a beautiful black female flying from flower to flower. Soon there will be lots of these large friendly bees zooming around. As my two-year-old daughter and I play in our front yard, yesterday, we watch a pair of Bushtits searching through one of the oaks that line the edge of the lawn. A pair of Bushtits (the same birds?) have built their hanging pendulum of a nest and raised a clutch of babies in this same oak tree for the past two years. Will this be year number three? Laying on the lawn, we find the remains of last year’s nest which has only now fallen from where it hung. The long sock-like construction of moss and lichen and feathers all held together by spider silk is soft to the touch and impressively flexible and elastic! We also see American Crows starting work on their nest. The pair, and a few helpers, have chosen to nest near the top of one of the redwood tress in a neighbor’s yard. Some crows (again, maybe the same ones?) nested in this same tree two years. Last year they moved about 100 meters away and nested in a pine, but now they are back to their redwood tucking sticks together just a few feet from the top of the tree. While this breeding activity is ramping up, there are still many winter birds readying themselves for their vernal migration away from the central valley. Ruby-crowned Kinglets and Yellow-rumped Warblers call as they forage in the trees finding insects and building up energy reserves for the trip to the breeding grounds and the marathon that is a birds breeding season. Cedar Waxwings are also still around in fairly high numbers. Recently, there have been so many in the sycamore trees right outside our door that their high-pitched calling becomes a constant background noise behind any other activity. So much to watch and enjoy. I hope early March where you are is just as fascinating and enriching.

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I have now begun to officially keep a phenological record.  Phenology is simply the study of the timing of events in the annual cycles of plants and animals.  All the great natural historians (Aristotle, Darwin, van Humboldt, Carson, Thoreau, Huxley, Linnaeus, Wren, Audubon, Skutch) kept this kind of data.  They recorded when birds arrived or left on their migrations, when flowers bloomed, when the leaves fell, when ice formed and broke up.  Aldo Leopold, one of my personal heroes, was famous for keeping detailed records of all the comings and goings that took place at his farm in the Sand Counties of Wisconsin.  These records are now being continued by his daughter, and they form an incredibly detailed record of a wide variety of events.  Other groups also collect phenology data; for example, the National Oceanic and Atmospheric Administration (NOAA) has been compiling weather data for more than a century.  Collections of these types of data sets have been vital to the measurement of global climate change.  Only from having long standing and continuous records of when the first individuals of particular species of birds arrived in spring or when the first snows fell in the mountains can we observe and track the slowly changing variations that are occurring on a planet wide scale around us.

To add to this endeavor in some small way, I will be tracking the occurrence of events in Central California.  I am not even attempting to track every possible natural history event.  When weather, animals, plants and fungi are all considered, it is clear that this would be impossible.   Instead, my hope is to track some significant events from season to season and year to year, and to add more and more such events as time goes on.

My calendar can be found under one of the tabs on my blog’s homepage and also at:


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