Silent sky

Several lines of evidence suggest that we are living in the middle of one of earth's periodic mass extinction events. It's the 6th one if you are keeping count of such things. The most recent previous mass extinction was about 66 million years ago when (most likely) an asteroid took out 3/4 of the plant and animal species on the planet, including most of the dinosaurs. Some of the dinosaurs did manage to escape; their decedents diversified into the myriad types of birds.

The jury is out on whether birds will manage to escape the current mass extinction---- a mass extinction that is being driven entirely by our actions. The extinction of a species is the last step on a sequence of events that begins with the loss of individuals and populations. This recently published study reports that there are 29% fewer birds in North America (in terms of abundance) than there were in 1970 (the year I was born). 
https://science.sciencemag.org/content/early/2019/09/18/science.aaw1313

That's 3 billion less birds hopping and flying around us than when my mom and dad brought me home from the hospital. This shocking realization has gotten a lot of press. Here is one of the many stories reporting on the study from the Washington Post:

https://www.washingtonpost.com/science/2019/09/19/north-america-has-lost-billion-birds-years/

As that article points out, other studies in other regions have reported similiar declines, and not just for birds (check out the links in the Washington Post story).

Partly because we are living through the changes in real time, and partly because the cause of the mass extinction are actions that largely make our lives happier and easier, we are not as alarmed about things as perhaps we should be. But in biological terms, we have self inflicted our own world altering asteroid strike.