Phenology is an old-fashioned discipline, dependent as it is upon an observer staying in one place for several years. Who does that any more? I did for quite a few years, but for the time being I’m unmoored.
You could think of phenology as a blend of chronology, accounting, and natural history. It boils down to keeping records of when certain natural events happen each year in a certain place. The observer, of course, must be able to differentiate species of plant and animals; otherwise the records would be completely subjective and difficult to share with other record-keepers. Linnaeus’s wonderful idea lives on!
In the pre-computer era (most of human history) phenological observations were kept in notebooks. Aldo Leopold and his family wrote their observations in the day-squares of a large calendar, another common approach. A year-end task was transcribing those notes to a notebook so that the calendar could be disposed of.
I must confess that any phenological observations I make are a byproduct of photography. How fortunate that digital photographs, like all computer files, are intimately associated with their date of creation!
Here’s my slender contribution to Southeast Arizona phenology.
The desert spring is quite unlike those of northern climates. Many of the trees (including many oaks) are evergreen here, so there isn’t the dramatic budding, unfolding, and awakening I grew up with. Many of the plants here wait for the late-summer monsoon rains to make their growth. Still, there are a few spring ephemeral plants. One of them is the Golden Corydalis (Corydalis aurea), a beautiful and dainty plant closely related to the Dutchman’s Breeches and Bleeding Hearts common in Eastern woodlands and gardens.
I first saw and photographed this Corydalis last spring, and I had a vague idea or hunch that the flower bloomed earlier last year. Sometime in early March, I was certain, but only the existence of the photos I shot last year provided me with evidence of the flowering date. Here’s a close-up I shot last year on March 6th:
This year the plants waited two weeks longer to bloom; I shot these photos a couple of days ago, on March 19th:
Naturally I wonder about the possible reasons for the delay. We did have an unusually chill and snowy winter. Many spring ephemeral plants bloom when the soil has warmed sufficiently. Now I wish I had records for previous years!