Project Prairie Birds

A Citizen Science Project for Wintering Grassland Birds

Background


Long Prairie Grasses

Some of this country’s most imperiled species are grassland birds such as Nelson’s Sharp-tailed and Henslow’s sparrows. (See the Henslow's Report.) Each winter season, many species of grassland birds migrate to the southeastern United States including Texas. Over a dozen species of sparrows along with the Eastern Meadowlark and Sedge Wren winter in a mosaic of remnant native prairie, agricultural fields, grazing pastures, and hedgerows.

Photo Common yellowthroat Copyright Michael L. Gray

Common yellowthroat
Photo Copyright Michael L. Gray

One of the highest priority species of the group, Henslow’s Sparrow, was potentially resident in the tall-grass prairies of the Upper Texas Coast; however, with loss of over 90% of these tall-grass prairies, that population has not been observed breeding since 1982. Other populations of Henslow’s Sparrow do use the remnant prairie in winter, but in unknown densities and distribution. In addition, in recent years there has been concern in the scientific and birding communities about the population trend of the Henslow’s Sparrow. The North American Breeding Bird Survey (BBS) data clearly indicate a population decline. Christmas Bird Count (CBC) data also indicate declines on wintering grounds. However, because of the secretive nature of this species those data gathered by the BBS and CBC may not reflect true population trends. As such, we are proposing a relatively new technique for censusing winter populations of Henslow’s Sparrows and other grassland species of concern. The Henslow’s Sparrow is not the sole focus of this study, it is merely the poster child.

The Origin of PPB Methodology

One of the largest, best-maintained areas of the longleaf pine forest ecosystem is on Fort Polk in west-central Louisiana. Military training on the installation causes many small to very large wildfires that maintain the bluestem community that is a signature component of the longleaf forests in this region. The military actively supports research of potentially sensitive species, such as Henslow's Sparrow, that could be impacted by their training. In an effort to assess the abundance and distribution of the Henslow's Sparrow on the installation, staff from Fort Polk Enivronmental and Natural Resources Management Division developed a survey protocol to collect population data on the species. Normally, grassland bird species can be effectively counted using rope drags, where two individuals simply drag a rope of fixed-length across the herbaceous vegetation and count birds as they flush away from the rope. However, rope drags were impractical on the installation since trees were located on all the proposed transects, making a continuous, uninterrupted survey impossible. Staff then developed the pole technique that enabled them to create a zone of disturbance much like a rope drag does, but also allows surveys to continue uninterrupted through the trees.


For Additional Information write to:

Project Prairie Birds Program
Texas Parks and Wildlife Department
4200 Smith School Road
Austin, TX 78744
or send a message to: nature@tpwd.state.tx.us

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