This gallery contains 2 photos.
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
This gallery contains 2 photos.
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
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 … Continue reading
This gallery contains 3 photos.
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
This gallery contains 4 photos.
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
This gallery contains 3 photos.
Dark-eyed juncos (Junco hyemalis) feed mostly on seeds and insects. In winter the junco’s diet consists mostly of weed and grass seeds, while in the summer insects are added. Juncos forage mostly while hopping and running on the ground. … Continue reading
This gallery contains 3 photos.
The Oriental turtle dove (Streptopelia orientalis) are found throughout Eurasia east to Japan. There are at least six subspecies. They inhabit the middle to low latitudes year round. Birds breeding in higher latitudes migrate south for the winter. Oriental turtle … Continue reading
