For the Birds Radio Program: Global Warming
Our climate is changing, and the changes are already affecting birds.
This was written after the United Nations Intergovernmental Panel on Climate Change released a report, in the summer of 2001. Date of this is uncertain, but it came out a week after the report was released.
This has been the first ” normal” winter we’ve had in north country in four years, with an abundance of snow and several spells of below zero temperatures. Weather didn’t stand in the way of the John Beargrease, and if anything, there was too much snow for the Birkebeiner. I’ve talked to a few people who got spoiled by the uncharacteristically mild winters of the previous few years and hated this year’s weather, but most of the people I’ve talked to lately seem relieved that we’re finally getting a real winter again–yesterday I took a picture of my neighbor by the snow bank in front of her house so she could send it to her friends. What good is it to live in the northland unless we can at least occasionally boast to our friends about wintry weather?
But even in the face of this normal winter, I’m worried about global warming. Of course there will always be birds-but more and more of them are gulls and crows, fewer and fewer of them Scarlet Tanagers and meadowlarks. The problem for birds isn’t that they can’t survive warmer temperatures-most birds adjust the number of down feathers they produce in response to temperature and thus can easily adapt to different weather conditions. The problems they face from gradual warming are more subtle. For one thing, milder conditions allow many southern plant species to extend their range northward, crowding out hardier but less aggressive natural northern species. The animals that require those northern plants have to follow them north.
Birch trees throughout the northern hemisphere have been succumbing to various diseases, quite possibly because acid rain makes them more vulnerable and milder winters allow the disease organisms to flourish. This decline in birches has led to a decline in Redpolls. This winter they were few and far between until the last few weeks, and even now all the flocks seem to be concentrated in the country. Many places simply have none. As any species declines, the remaining individuals naturally fill up all the best habitats first, and a lot of my favorite northern birds are virtually never spending time in Duluth anymore except as they migrate through. I haven’t had a Pine Grosbeak at my backyard feeder in a decade now, though the first ten years that we lived in Duluth they were sparse but regular here in winter.
The changing weather patterns have led to genuine changes in how creatures respond to the seasons. Continent-wide, tree swallows lay their eggs nine days earlier than they did in the 50s. The United Nations Intergovernmental Panel on Climate Change issued a report last week stating that more than 80% of the 500 species studied, including birds, mammals, reptiles, amphibians, mollusks, insects, other invertebrates, and plants, are changing in response to rising temperatures. Some birds migrate up to three weeks earlier now, and some migrate well outside of their natural range, edging closer to the poles and living at higher altitudes. Satellite images and lake ice-outs indicate that spring begins 11 days earlier than it did in the fifties. This warming is affecting the timing of a huge array of natural events, including when cherry blossoms bloom, birds migrate and lay their eggs, aphid eggs hatch, and toads breed. Species timing their spring events by daylength are being crowded out by those that start earlier now in response to temperature.
We’re at a crossroads. We urgently need to confront environmental issues that haven’t been seriously considered by our government since the 1970s. We must address energy conservation and put serious checks on various pollutants soon. We’re robbing from our children’s futures and damaging the earth we were entrusted to use, not abuse. Attention must be paid.