For birds and those of us who regard them as environmental indicators, the news isn’t good. This summer we heard from the National Audubon Society that out of 600 species of common birds in North America, about one-third lost population in the last 40 years. Some species declined by 50 percent or more. The declines appear to be the result of habitat loss for the most part; some may be attributable to climate change and other factors. Whatever the reasons, there’s cause for concern; what happens to birds is also happening to the fish (if you doubt that, check groundfish landings in the Gulf of Maine or statistics on whale or tuna populations worldwide) and what happens to them will inevitably happen to the rest of us. A sobering thought, to say the least.