Friday, May 28, 2010
Over the last three weeks, I've been rising early and heading out to one of my two study lakes to locate the nests of largemouth bass. At the same time I've been scanning the depths to identify nests, I've noticed something strikingly different between areas of the lakes that are developed and those that are either lightly developed or not developed at all. Most obvious to even the most casual observor is the change in vegetation. Developed shorelines, i.e. those with residential-like houses and yards, feature mowed yards and large mature trees. Undeveloped shoreline, or that which is relatively undeveloped, has a number of large mature trees, a large number of smaller trees, a layer of shrubs and a wide variety of ground covers, many of which flower in the spring. But that's all pretty obvious. What is less obvious but perhaps even more disconcerting is the differences in the avian communities that I saw, and heard, over the last three weeks. Consider these two lists, first a listing of birds from yards, or developed shorelines: Grackle, American Robin, Canada Goose, Northern Oriole, Red-winged Blackbird, Chipping Sparrow, American Crow, and Eastern Wood-Pewee. The second from shoreline that hasn't been developed, or lightly so: Yellow-headed Blackbird, Common Loon, Indigo Bunting, Northern Oriole, Bald Eagle, Golden Crowned Kinglet, Ovenbird, Rose-breasted Grosbeak, Scarlet Tanager, and Pileated Woodpecker. Most of the species seen in the developed areas where also seen at the less developed areas as well; meaning the diversity was substantially higher at the undeveloped areas. The point is birds that are normally what we consider "park species" or ones that anyone can see in their back yard are now common along our lakeshores. The dramatic habitat alterations that occur with development have altered the types of birds that frequent these areas. Yet this isn't new, more than 10 years ago biologists in Wisconsin were documenting these changes. You can read more about it here. The sad part is, the areas that I was seeing and hearing the greatest diversity of birds is currently being developed. By 7:30 a.m. each morning the sounds of grosbeaks, orioles, and yellow-headed blackbirds was replaced by the roar of bulldozers and chainsaws.