Birds on our porch

So for the past week, we've been watching a pair or sparrows or finches (I don't really know what they are, but they're smallish) build a nest in one of our hanging plants on the front porch. The plants require watering every two or three days, or they become kind of wilted, so I've been trying to be careful. Yesterday, I noticed that I hadn't seen the pair, and so when I watered the plant, I pulled it down from the hook to see if there was anything inside. There is a tiny nest that could fit in the palm of your hand, and inside the nest is a small, speckled egg. I carefully rehung the basket, noting on which side the nest was, so I didn't cover it in water.

Then I noticed the concrete below the plant. There were the remains of a different, light blue, non-speckled egg, shattered around its dried yolk. Some other bird threw out the original pair's egg and stole the nest from them. I haven't seen the original pair again, and I also haven't seen the nest-stealing culprit. The egg remains.

There is an overwhelming part of me that tells me this is awful and wrong. But that's me applying my human morality to nature. The original pair worked hard for days to build that nest. They gathered weed stems and tender twigs. They plucked their own down feathers to line the inside. They gently placed the product of their love (see, there's some more anthropomorphism) inside that nest. And some other species that has learned to survive by conserving it's own energy and taking advantage of others destroyed that potential offspring and stole their spring home. Are these birds seething in rage? Are they plotting revenge? Should I lie in wait to find the intruder to enact justice? Or have they simply moved on?

The original birds are without our attachments, and they will trudge on. If there is time in the season, they probably have already started a new nest and new egg somewhere else. And the intruder will trudge on as well. They do what they do. I still feel sadness at the way in which the world sometimes works, but there is a lesson that little bird family can teach me.