Now, I know what you're wondering, where's the picture of the dead bird? Yeah right. Like I said I slammed the door and ran and didn't return until the carcus was long gone. I did, however, take a picture of the killer cat.
In the case of the cat and blue bird, the cat played the role of the predator (the chaser) and the bird was the prey (the chased). Unlike most predator-prey relationships, the cat did not feed on its victim. Interestingly enough I know that blue bird nests are often overtaken by the Sparrow, another inhabitant of my backyard. When Sparrows overtake a nest or smash the eggs of blue birds the blue bird again becomes the prey. The Sparrow and Blue Bird compete for resources (food, shelter, etc) within their niche (the way a species lives within their ecosystem).
OK, I'm starting to feel bad for the poor Blue Bird... NOT.
As I watch two Sparrows fly from bush to bush, I am thankful that they are there to eat all the insects and bugs (another example of predator-prey relationships). But don't think the Sparrow always wins. Cats often eat Sparrows. I noticed a black cat and an all white cat laying under my patio furniture. Where did these feral cats come from and why are they here? Are they competing with each other to catch the Sparrows for food? Or are they stealing my cats food that is kept on the back porch? Also, I've heard that parasites kill Sparrows (an example of a parasitism, when one organism feeds on another)
Is it going to far to say that the interactions between the Cat, Sparrow, Blue Bird, and Parasites is an example of a food web?

I realized that I haven't spent a whole lot of time in my backyard this winter. Because as I was sitting there I noticed my bike. covered in vines and moss. I had stood my bike up against the chain link fence and forgot about it. The vines grew up and around the bike making it almost impossible to see. When a species uses another species to grow and thrive like this without having a negative effect on the original species it is known as commensalism. In this case my bike is an abiotic (non-living) species. Here is a picture of my poor bike. I really don't think I'll be able to save it, it looks pretty rusted under all that bush.

Like I said, I originally never anticipated being able to complete this assignment from the top step of my back porch. I guess this shows that "nature" doesn't have to be on a mountain top or a hiking trail or out on the beach. I encourage you to conduct your own nature observation in a simple place and see if you're surprised by the things you see.