Tuesday, October 24, 2006

Bye Bye Birdies: scary trends

This evening I was looking at e-Bird data, particularly checking for regions where there is enough "old" data (pre-1990) to maybe get some sense of decade-to-decade trends. In most regions there really isn't much older information to speak of; but one of the places there is, is the Piedmont. This is the plateau between the Appalachians and the Coastal Plain from Alabama to Maryland; pretty much the I-85 corridor and much of metro DC. This is where I grew up (Atlanta), and some of that pre-1990 data is actually mine. So I looked at the abundance bar graphs for before 1990 and after 2000 and compared species by species. It was frightening.

As a preface, note that the Piedmont has underone MASSIVE and RAPID land use change and population growth in this time. The earlier landscape of farms and oak-pine woodlots separating discrete cities has been replaced wholesale with suburb upon suburb. Over vast areas the suburbs have run together; what we used to call BosWash (the northeastern urban corridor from Boston-Washington) is now more like Bostingham, having grown all the way to Alabama. This is in fact one of the major reasons Peggy and I do not live there anymore. And what has happened to the common birds here, in my quick and dirty estimate?

Well, for four species, the change has been good: Canada Goose, Ring-billed Gull, Fish Crow, and House Wren have all increased. But for the others, it is a catastrophe. About 90 common (at least formerly common) species seem to have declined notably region-wide; nearly 50 of these have declined quite substantially, many to the point that a species that was common in my youth is now rather scarce. This includes residents, breeders, winterers, and transients; it cuts across the habitat preferences, migratory patterns, and taxonomic groupings. We can't blame this on far-away lands; this is a home-grown distaster. Folks, 90 species is right about half of all the species that used to be common here.

A sampling of the once widespread species that appear to have dropped off sharply include: Northern Bobwhite, Green Heron, Great Crested Flycatcher, White-eyed Vireo, Northern Rough-winged Swallow, Blue-gray Gnatcatcher, Swainson's Thrush, Brown Thrasher, Tennessee Warbler, Chestnut-sided Warbler, Common Yellowthroat, Field Sparrow, Savannah Sparrow, Blue Grosbeak, Indigo Bunting, Eastern Meadowlark, Rusty Blackbird, and Orchard Oriole. The main thing all these birds have in common is that they don't like neat, tidy, Dixie-style suburban landscaping. They like brushpiles, weedy edges, farm ponds with brambly shores, mixed species woodlots, underbrush, field and pastures... all the landscape elements that vanish with residential development. When I was a kid in Atlanta, all these things still existed even around the older neighborhoods in the city. But thanks to "infill" development they are a thing of the past. The Piedmont is one of the worst case examples, perhaps; but the pattern is happening everywhere.

Land use, folks. Right here at home. This is the biggest threat to our birds and all the rest of the entities that comprise our ecosystems. We can fight all the global warming and tropical deforestation we want, but if all we have left back home is shade trees, manicured lawns, strip malls, and soccer fields it hardly matters. Weeds and woods and willows and brambles and "trash trees" can be incorporated into our landscapes from downtown to the outermost edges of the suburbs. Sad, that it is landscaping fashion and the inexpensive gasoline-powered lawnmower that are eradicating our birds.


At 8:27 AM, Anonymous Anonymous said...


This is a sad but interesting tale of our abuse of the natural landscape and apparent inability to do anything about it. I cross over the Blue Ridge and through the Piedmont daily to a job in northern Virginia, and have witnessed the very type of rampant development that you describe. In my commute, I experience the displeasure of driving through several of the 100 fastest-growing counties in the U.S. It especially pains me to see residential development creeping up the slopes of the Blue Ridge Mountains along the border of Virginia and West Virginia. It was in this and surrounding areas in the mid-1970s that Chan Robins et al. developed their concept of minimum patch-size and the effects of deforestation on forest-nesting birds. The county in West Virginia in which I live has been experiencing a tremendous influx of people from the Baltimore-Washington corridor. Until now, incredibly, our elected county commissioners have been opposed to zoning. I'm hoping that will change with the upcoming election.

At 8:58 AM, Blogger Bill Pulliam said...

Northern Virginia and north Georgia are twin nightmares in this regard. The Colorado Front Range (from which we just moved) is another pup in the same litter. It's not just a function of population growth; it's especially being driven by the expansion of the size of each individual homestead. I'm afraid little short of $10/gallon gasoline will put the brakes on it. Local planners are almost universally controlled by real estate and development interests nationwide. Amusingly, the thing that has finally gotten our county planners here to think about zoning is the threat of adult entertainment establishments! After all, bare boobies are truly the biggest threat to the quality of life and environment here.

I have not seen that environmentalists and conservationists are necessarily all that clean in this regard as it relates to their own lifestyle choices. They still have a tendency to want to buy and build their own little getaways out in "the country." So they by 20 or 90 or 200 acres of "undeveloped land" just beyond the outer suburbs and put a house on it. But rather than escaping suburbia, they are really just helping to draw the suburban frontier forward. Their very presence results in things like power lines and phone lines and roads being extended to their little hideaway. Now, with the infrastructure in place, development inevitably follows. This was a major factor in our buying a place on existing infrastructure with an existing house. Sure, we have neighbors and cars (one or two an hour) going by, but we ourselves have not added to the sprawl.

At 8:17 PM, Blogger sparsegreyhackle said...

Sorry about my late comment but I am a new visitor.

This trend is scary, and appears irreverible. Somehow, and Zoning is the likely mechanism, we are going to need to find a way to create patch sized buffers inside these sterile developed areas. There has been some success along this line in the Lower Rio Grande Valley. Developers and the powers that be have recognized the economic advantage to doing this. The money birding tourism brings to the Valley is a very strong incentive. Local kids are encouraged to appreciate the unique flora and fauna of their area and most adults take some pride in this as well. The area is still a disaster but there is a concerted effort at all levels to create pockets of good habitat.That formula probably won't work everywhere, but I think that educating the public on the need for wildlife oasis will go a long way towards educating the politicians and their close friends the developers. Of course this is much, much easier said than done. Bottom line is that the general public has no idea what is being lost. They see an abundance of house sparrows and starlings and complain about "too many Canda Geese" so they think all is well. Somehow they need to be informed as to the problem and encouraged as to the solution. A daunting task, indeed.

At 6:20 PM, Anonymous Anonymous said...

Bill; This stuff deserves to be published. I remember in my youth in northern Virginia you could find various "weedy field" species not seen anymore, e.g. Henslow's sparrow; and many of the species you mention are difficult to find. I now live in Montana, and a parallel problem has occurred: all the riparian shrub/tree breeders (a super rich habitat occupying only 1-2% of the semi-arid landscape--like the front-range of COLO)have been shown to be unsuccessful breeders with 1/4 mile of human habitations....probably a combination of cowbird density and predators. So even if they haven't disappeared in these suburbanizing areas, those habitats become population sinks.


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