Important Bird Areas

Hamden Slough NWR IBA

Minnesota

Eastern forests dramatically give way to the western prairie at Hamden Slough National Wildlife Refuge. Hardwood forests stretching from the Atlantic seaboard, rapidly transition to the vast western prairie grasses at this picturesque refuge. This biological diversity of vegetation is highly attractive to wildlife, especially migratory birds. Over the past 100 years, intense agriculture and the associated draining of wetlands has had cataclysmic effect on this historic wildlife area. In the north central plains, an estimated 99% of the Tallgrass prairie has been plowed under, and over 90% of the prairie wetlands drained. Around Hamden Slough NWR, more than 55,000 wetlands have been drained. This loss and fragmentation of the prairie has resulted in a precipitous drop of prairie wildlife populations. Most notable during the last 30 years, has been the decline of migratory prairie bird populations. Hamden Slough NWR when fully restored will provide the largest contiguous block of wetland-prairie habitat in the region encompassing nearly 6,000 acres. Many species of waterfowl, including the Eastern Prairie Pothole population of Canada geese, shorebirds, marsh birds, neotropical migrants, and avian predators rely on the shallow-water and prairie habitats that have been restored on the refuge. The station?s objective is to restore/enhance 3,000 acres of wetlands and 2,250 acres of upland grass. During the last 5 years alone, refuge restoration work has resulted in an explosive growth of marsh and shorebird populations, including a sighting of the endangered piping plover. John James Audubon?s niece heard about the wildlife abundance of the Hamden Lake area and visited the site in 1871. With her were the Minnesota governor and 18 other respected colleagues. They were so impressed with the abundance and diversity of wildlife that Audubon?s niece asked the governor to name a township for her famous uncle. Today, the Hamden Slough National Wildlife Refuge headquarters office sits in Audubon Township, one mile from the city of Audubon.

Stories of Hamden Lake?s wildlife prominence have been related by the area?s older citizens, such as: 1) ?My father shot whooping cranes, swans and blue cranes.? 2) ?My uncle ? got 13 mallards with one shot.? 3) ?She used to catch Northerns (pike) that weighed 11 pounds!? and 4) ? ?would have a whole triple wagon box full of hides to sell.? And many early pioneer families survived by hunting and fishing, including children throwing sticks in the air to knock down ducks for dinner.

Ornithological Summary

Hamden Slough National Wildlife Refuge (HSNWR) is an important site for Minnesota?s birds based on species information collected during the past two years. Three research studies were conducted at HSNWR which included a shorebird survey, bird point count survey, and a marsh bird survey. The shorebird surveys were conducted during the spring and fall migrations in the years 2002 and 2003 over twelve survey plots. The prairie bird point count survey has been conducted over a period of five years beginning in 1994, 1995 and 1996. The point counts were reestablished in 2002 and 2003 with GPS (Global Position System) locations added for each point. The marsh bird survey is part of a standardized North American marsh bird monitoring effort for National Wildlife Refuges conducted at HSNWR in 2003. Minnesota Important Bird Area justifications and site criteria are based on the data obtained during these three research projects. HSNWR supports a minimum number of breeding pairs of Pied-billed Grebe based on results from three surveys during the breeding season 2003 using the marsh bird survey results. The marsh bird survey has 19 different points within HSNWR which were surveyed three times during the breeding season in 2003. The first survey on June 4 resulted in call-back data from 19 individuals. The second survey on June 18 resulted in call-back data from 20 individuals. The third survey on June 27 resulted in call-back data from 25 individuals. Other waterbird species recorded during the marsh bird call-back surveys included Black Terns (51 highest count), American Coot (24 highest count), Sora (14 highest count), Virginia Rail (15 highest count), American Bittern (7 highest count), Least Bittern and Great Blue Heron. Combined with the Pied-billed Grebe count this brings the mixed species category over the minimum of 100. HSNWR has conducted shorebird surveys following the procedures outlined by Manomet Center for Conservation Sciences, International Shorebird Survey protocol during spring and fall migrations in the years 2002 and 2003. Shorebird surveys were conducted every 7 to 10 days during the migrations with a shorebird species total of 23 species in 2002 and a total of 24 species in 2003. Threatened species ? Wilson?s Phalarope (shorebird surveys, and point count surveys).
In the category Of Special Concern: Greater Prairie Chicken (established lek on refuge), Common Moorhen, Marbled Godwit, and Nelson?s Sharp-tailed Sparrow have been recorded for the years 2002 and/or 2003 during shorebird surveys, prairie point count surveys and marsh bird surveys. Species found during point counts and/or shorebird surveys at HSNWR include:

Northern Harrier
Nelson?s Sharp-tailed Sparrow
Upland Sandpiper
Wilson?s Phalarope
Vesper Sparrow
Grasshopper Sparrow
Bobolink
Brewer?s Blackbird
Sedge Wren
Marbled Godwit
Dickcissel
Savannah Sparrow
Clay-colored sparrow
Le Conte?s Sparrow
Western Meadowlark

Conservation Issues

One hundred years of agricultural development has resulted in the loss of 100,000?s of acres of upland and 100% drainage of all Type I, III, and IV wetlands in western Becker County, Minnesota. As a result, the water in a wetland?s sub-watershed carries far higher sediment loads. A watershed?s Time of Consolidation for water has also changed from weeks or months, to hours. As an example, the refuge restored 70 acre Homstad Lake has a 2500 acre watershed from private cropland. Prior to drainage, the water received in Homstad Lake took weeks to pass through a series of wetlands, and contained little if any sediments, pollutants, or high water volume. With cropland drainage on private land, the Time of Consolidation for Homstad Lake has been reduced to 12 hours and sediment loads are high. Restored wetlands absorb these higher levels of nutrients, and also have rapid rises in water levels, which inundate nests and vegetation.

Invasive and native pest plants are in the area and on the refuge. A small stand of leafy spurge has been eliminated with Black beetles. Small stands of spotted knapweed and purple loosestrife are removed yearly, by hand. Thistles and other weeds are mowed on hundreds of acres, particularly for two to three years after a native seed planting. Hybrid cattail is tenacious and replaces more diverse aquatic vegetation. The refuge?s first cattail spraying will take place in 2004.

Roads can be a minor disturbance, but also provide the visiting public with good access. Avian predators near roads, take wing if vehicles slow or stop. The refuge?s first prairie chicken dancing ground was observed in 2003. Many visitors used the county road to observe the birds, without any known disturbance.