根据短文内容，从短文后的七个选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。
For serious birders who regularly observe birds in the wild, ignoring climate change isn't possible. We have been seeing and documenting the effects of a warming climate since at least the 1950s.
Glossy black great-tailed grackles (美洲黑羽椋鸟), for example, previously found primarily in the tropics (热带), first reached southeastern California in 1964. They are now found throughout most of the state.
New research from the National Audubon Society highlights the dangers of the trend. For its new report, "Survival by Degrees," Audubon scientists analyzed the current geographic ranges of 604 North American bird species, and modeled how those ranges would change at different levels of warming. At a global temperature rise of three degrees Celsius, they found that 389 of those species—or nearly two-thirds of those studied—would become endangered, losing much of their current habitat.
Why does this matter to anyone who's not a bird watcher? For one thing, birds play a crucial role in the ecology, keeping down insect populations and serving as food themselves for larger predators (食肉动物). Their shifting ranges warn of increasing droughts, floods, fires, rising seas and unlivable cities.
Audubon scientists modeled what would happen at lesser levels of warming, and the results are striking. Limiting warming to 1.5 degrees would reduce the danger for three-quarters of those threatened birds. Audubon's report "Survival by Degrees" is not a depressing forecast but rather a call to action. It stresses the need for action at every level, by individuals and governments alike, to reduce greenhouse gas emissions.
As a lifelong birder, I'm proud of the role my tribe has played in documenting the effects of climate change. When local conditions change, particular types of frogs or wildflowers may decrease and disappear, few will notice. I hope people can pay close attention to the urgent message in this new report and work together for solutions. Birds tell us we don't have time to wait.
A. We still have time to do something about it, however.
B. But they also serve as a visible symbol of broader environmental shifts.
C. This would greatly benefit humans, reducing the potential suffering for people.
D. But when a bird species disappears, we dedicated birders document the change.
E. In recent decades, that has meant a consistent northward shift in where species are found.
F. The changes will make birding exciting, with birders finding new species in unexpected places.
G. Even if some could shift their range northward, they would soon start to run out of room on the map.
