Inventorying Birds in the Silvies floodplain

Written by Teresa Wicks/Photos by Teresa Wicks

The flood-irrigated ranchlands of the Silvies Floodplain support large numbers of migrating waterfowl and waterbirds through providing a place to stopover and rest while making their journey north. Up to 30% of the Snow and Ross’s Geese that navigate the Pacific Flyway, the westernmost “highway of the sky,” depend on the Harney Basin (and nearby Summer Lake) for a place to rest, feed, and store plenty of energy to make the trek to their breeding grounds. For Ross’s Geese, this is the arctic tundra of northern Canada, while Snow Geese prefer the coastal tundra of the arctic and subarctic zones of northern Alaska and northern Canada. These ‘white geese” are not the only migrants that depend on the flood-irrigated wet meadows of the Silvies Floodplain; Northern Pintail, shorebirds, Lesser Sandhill Crane, and some songbirds depend on the nutrient-dense grasses, insects, and rhizomes of the floodplain during their migratory travels. Additionally, breeding Greater Sandhill Cranes, Black-necked Stilt, Wilson’s Snipe, Long-billed Curlew, and songbirds like the Red-winged Blackbird, nest in these wet meadows.

In 2019, in an attempt to understand the diversity and relative abundance of birds using the Silvies Floodplain, the seasonal variation in bird communities, and how bird association changes with life cycle, Portland Audubon developed Project IBiS (Inventorying Birds in the Silvies Floodplain). In order to answer these questions Portland Audubon volunteers survey from the perimeter of each site, along public roads, stopping at points located approximately ½ mile apart. At each stop, all bird species are identified and counted, including flyovers.

In the first year of the survey, eight volunteers collected data from March-May. These volunteers detected 60 species, comprising 8379 detections, 5000 of which were Snow/Ross’s Geese! Northern Pintails were the next most abundant waterfowl species, followed closely by migratory Sandhill Cranes. Blackbird species were the dominant songbird species, with Red-winged Blackbirds having the highest relative abundance, followed by Yellow-headed Blackbirds.

In 2020, it is the intention of Portland Audubon for a subset of volunteers will be trained on a more rigorous survey, collecting additional data including distance bands (e.g. <50 m, 50-100 m, 100-200 m, and >200 m), breeding codes (see Appendix 2), type of identification (e.g. singing, visual, or flyover), and habitat variables (e.g. percent cover water). Portland Audubon is working with the Agricultural Research Station to develop a basic training guide for identifying dominant grass types, in an effort to create more synergy between this project and the vegetation surveys currently being conducted by Harney Basin Wetlands Initiative partners throughout the Harney Basin. Additionally, in an effort to gain a better picture of changes in wet meadow bird communities throughout the year, data will be collected from January-November of 2020.

If you would like to be a part of this Project, visit Project IBiS page of Portland Audubon’s website where you can learn more and read the survey protocol. Alternatively, contact Teresa Wicks, twicks@portlandaudubon.org