Bergmann’s Rule

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Bergmann’s Rule (the third ecographic rule) was formulated in 1847 by Karl (also seen as Carl) Bergmann (1814 – 1865), a German biologist. It states that the same or closely related species tend to be larger in colder climates. It … Continue reading

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Allen’s Rule

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There are three principal Ecographic Rules for terrestrial environments: Allen’s Rule, Gloger’s Rule and Bergmann’s Rule. Ecographic Rules are concerned with variations in traits (mainly morphological) of organisms over goegraphical gradients. Allen’s Rule was discussed previously. (see “Gloger’s Rule” 10-10-16) … Continue reading

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Finally!

Sandhill Cranes

With the arrival of February Leonard and I begin to listen and watch for the sandhill cranes (Grus canadensis). Usually we hear the far-carrying, loud, guttural bugling of the cranes before we see them.

So far this year February has been bitterly cold with snow covering the ground. Although the sandhill cranes usually arrive between the 13th and 18th of February, with February 6th the earliest return I recorded, as of yesterday they still were not here. We joked that no sane sandhill crane would migrate back to such unwelcoming weather.

This morning Leonard and I went across our road to the Ash Creek Wildlife Area (Modoc County CA). Much to our surprise we saw ten sandhill cranes probing in the fields. We saw them before we heard them this year. The sandhill cranes probably arrived overnight. As we hiked around their calls began to fill the air, we saw more sandhill cranes and several flocks of cranes flew overhead.

Sandhill cranes are diurnal while migrating, often flying high in V formations or in well-spaced lines. They migrate in flocks, pausing at traditional stop-over points. Young cranes learn the migration routes from their elders. Their migration routes are not instinctual. Although many of our spring visitors move further north for the breeding season, a large number of sandhill cranes remain throughout the summer and breed here in Big Valley.

Even though our landscape remains covered in white, the return of sandhill cranes signals spring.

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Roundtooth Ookow

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Roundtooth ookow (Dichelostemma multiflorum) is a member of the Asparagus Family. The etymology of ookow is obscure, but is likely Native American in origin. Other common names for D multiflorum are wild hyacinth, roundtooth snakelily and manyflower brodiaea. A native … Continue reading

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Pacific Treefrog

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Pacific treefrogs (Pseudacris regilla) are amphibians. Derived from the Greek “amphi”  and “bios” meaning “both” and “life” respectively, amphibians inhabit water early in their lives and then change to a form that can live on land. Pacific treefrogs are small, … Continue reading

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Wondering?

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For nearly 30 years Leonard and I have observed the red-tailed hawks (Buteo jamaicensis) in Big Valley (Modoc County CA). Not long ago as we were counting red tails along the road, I commented that the number of melanistic red-tailed … Continue reading

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Melanins

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Social Signaling A book I received for Christmas got me interested in melanins in bird feathers. Melanins are pigments found in most organisms. Their chemistry is complex and their functions in many organisms are not understood. In birds they are … Continue reading

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