The first two weeks of June is quite possibly my favorite time to bird in New Jersey. Migration is fun and all, but I love searching for breeding birds. Its like a well studied treasure hunt; you bone up on habitat requirements and ID tips then hit the field hard. You get excellent opportunities for close behavioral observation, and of course, you can always dream of that tantalizing rare find. So when an associate called yesterday to say she had found a Sedge Wren in Somerset County, my coworker Thom and I dropped everything and were out of the door as soon as possible.
The Sedge Wren, a shy denizen of dense, grassy, and (usually) wet meadows, was once much more common in New Jersey than it is now. This species is part of a group of grassland obligate songbirds whose survival in the northeast has long been dependent on agricultural lands. An explosion of pasture farming in central New Jersey in the 19th and 20th centuries allowed these birds to flourish, but recently they have seen severe declines. Once widespread species such as bobolink, grasshopper sparrow, and eastern meadowlark have become only locally common. Other birds; sedge wren, upland sandpiper, henslow's sparrow, and dickcissel to name a few, have become exceedingly rare. The sedge wren itself has less than five known breeding records in the state in the last twenty years.
While it is true that these species existed in the northeast prior to widespread agricultural development, inhabiting natural grasslands in coastal locales like Long Island, by the 20th century their fate had been pinned to regional cattle farming. When local farmers began to dissappear in the 20th century, their tenant birds went with them. New innovations in agro-chemicals and labor saving machines were causing the practice of farming to rapidly industrialize. By the 1970s, 'agriculture' had largely given away to 'agribusiness', and the vast midwest became the undisputed center of our food production, funneling (primarily) corn into a long supply chain that ended in then relatively new supermarkets and fast food chains. Grassland birds were hit from both sides. The midwestern prairie, the stronghold of these and many other obligate species, was giving way to barren cornfields. Gluts of cheap food and fuel were driving rapid expansion out of major population centers, and the farmlands that once separated New York City from Philadelphia gave way to housing developments.
Somerset County lies at the crossroads of New Jersey's former farmland. At the turn of the 20th century, it was a vast expanse of pasture and hayfields, spanning from East Amwell practically to New Brunswick. One can only imagine the birds. Even eighty years later, large blocks of remaining grasslands were incredibly productive. Anyone familiar with the first edition of Bill Boyle's A Guide to Bird Finding in New Jersey surely recalls the entry on Beekman Lane, the Hillsborough road that bordered the eastern edge of the Orchard Road Grasslands Natural Heritage Priority Site. This was a place with an active colony of upland sandpipers, where such rare breeders as Dickcissel and Vesper Sparrow bred annually. Take a drive down Beekman now and all you'll find is Hillsborough Chase, an upscale Toll Brothers development.
Despite the loss of habitat, grasslands in Somerset & Hunterdon Counties continue to host impressive birds, such as this Sedge Wren. The continuing importance of this region for grassland bird conservation has been highlighted by the Raritan Piedmont Wildlife Habitat Partnership, a working group comprised of special interest organizations and local government dedicated to land preservation and stewardship. Some important reserves fall within the RPWHP area, including the highly successful restorations at the Negri Nepote Reserve, Duke Farms, and a large tract of preserved farmland in East Amwell. The goal now is to connect these key areas, largely through grassland restorations on public lands and aiding private landowners with the enrollment process for various federal and state wildlife habitat incentive programs. The property this bird was found on is in the RPWHP area.
From a birder's perspective, it is interesting to note the habitat- dry, upland hayfield. Definitely not what one usually pictures when they think 'Sedge Wren'. My guess is the dense, tall vegetative structure is the real key, and it just so happens this kind of habitat is usually associated with wet meadows. The bird was clearly on territory, though we were unable to confirm breeding. Definitely a great surprise on a balmy early June day! Photo by Thom Almendinger.
