I agree with Solitary, I think overpopulation is a huge problem for other species. Not only is climate change making it more difficult for birds to adapt but also habitat destruction is displacing them. If the habitat is destroyed then the food sources may decline, leading to a lot of displaced animals. Unfortunately many of those species may not be able to adapt to the environments in which they will be forced to live. Many people forget that it's not simply the space for our population to live, but also only a certain percentage of the land on earth is suitable for farming. As the population increases, the amount of land necessary to sustain food sources is going to increase. Therefore, you have more demand for farming land and more demand for space to house the population. I think it is tragic that many people, particularly some of the pro-lifers, don't see overpopulation as an issue.