Pause here, and observe all of the different organisms around-the trees, grasses, sedges, and birds. If you stand long enough, you will notice birds swooping in and out of the area, and eventually, you will distinguish the relationship between bird species with one another. You may see the smaller, bright-shouldered Red-winged Blackbird (Agelaius phoeniceus) chasing after the larger American Crow (Corvus brachyrhynchos). The male blackbird is defending his territory, and the noisy crow is infringing upon it, potentially endangering the female blackbird harem and their eggs. One red-winged blackbird has a group of females he mates with, who nest in his territory. The blackbird will watch over it, acting aggressively against anything that interferes. You may also witness a Great Blue Heron (Ardea herodias) scattering Mallards (Anas platyrhychos), perhaps in competition for a food source. Content that he will be able to get enough for himself, the heron goes on to hunt for dinner in the water. Still as ever, he is poised and snaps at the water, catching a small fish. Meanwhile, the crow and blackbird watch on from their respective trees.
Follow them there. Another interaction may be more difficult to see. The Pacific Willows (Salix lucida) to the left and right have small patches of a bright orange foliose lichen, the Xanthoria parietina. The lichen is a symbiosis of fungi and algae, and does not harm the tree. Lichens are a good indicator of air quality! Xanthoria parietina does well in areas with lots of nitrogen. (3) What do you think that says about this area?
Xanthoria parietina on a Pacific Willow
Speaking of nitrogen, look to the ground for our final ecological interaction. Bird droppings seem gross, but actually are beneficial to the ecology of the area. They contain high amounts of nitrogen and other natural fertilizers. As they decompose, the nitrogen is released into the soil and available for use by plants. If you look closely, you might even see one other beneficiary of this “waste”- a fly, order diptera. Flies feed and lay their eggs on these droppings. Everybody wins!
As you can see, there are a large diverse amount of interactions going on in just this one area!
No comments:
Post a Comment