As Joan Wickersham’s husband records, with alarm, the effects of climate change on birds, the natural world is shifting in other ways (“Birdwatching with 20-20 hindsight,” Opinion, May 29). In the 1850s, Henry David Thoreau kept meticulous notes on the dates when common trees and plants in Concord flowered, leafed out, developed seeds, and then shed fruit and leaves. Biologist Richard Primack has compared Thoreau’s records with the behavior of trees and flowers in the present time. Teams of volunteers (including me) at the Arnold Arboretum and Mount Auburn Cemetery now keep track of the same species that Thoreau studied. Leaf-out times, for instance, are 10 to 14 days earlier than in Thoreau’s time.
While some insects emerge earlier, migrating birds are not responding as quickly to our warming climate, especially those that travel long distances. This means that the insects on which birds rely — for sustenance and food for their fledglings — may already be gone when birds arrive.
Why should we care about these changes? Because we depend on the delicate web of birds, plants, and insects that pollinate the plants that feed us. And because, like Wickersham, we fear for the world our grandchildren will inherit if we don’t act now to reverse the earth’s warming.
Joan Wickersham poignantly captures our powerful connection to the natural world, especially to birdlife, and the reality that climate change is affecting bird populations (“Birdwatching with 20-20 hindsight”). Mass Audubon’s work over the past 50 years confirms that many Southern bird species are now widespread in Massachusetts.
But a warmer habitat that is hospitable for Carolina wrens and red-bellied woodpeckers is conversely a threat to other native species that have long called Massachusetts home.
Thirty percent of our breeding birds are already declining, and climate change increases stress on theseand other species. Our projections estimate that 43 percent of the common breeding birds we evaluated are highly vulnerable to climate change over the next 30 years, and that scale of change will result in losses that are both unpredictable and unimaginable.
But we can make a difference. By reducing carbon emissions, we can combat climate change’s impacts. By conserving open space and diverse wildlife habitats, we can help all people and wildlife fight and adapt to changes we are already experiencing.
As the thrilling recovery of bald eagles demonstrates, community action works. With focus and effort, we can protect the nature of Massachusetts for wildlife and for people.