Appendix F Detailed Cover Type Tables - USDA Rural Development

Bemidji – Grand Rapids
Biological Assessment and Evaluation
plumage with a pale‐gray wash, a completely pink bill, and yellow legs and feet. Leucistic
cygnets have only been reported in Red Rock Lakes National Wildlife Refuge, Montana,
at a 1.8% occurrence, and at Yellowstone National Park, Wyoming, at a 13% occurrence
(Mitchell 1994). The cygnets undergo a complete prejuvenal molt that begins around 6
weeks of age and is completed around 10 weeks of age. Between 12 and 16 months of
age, the bill will turn to the black adult coloration. The second year swans are mostly
white with a few pale‐gray or brown feathers on the head, neck, and body, and have
yellowish‐greenish gray to black feet and tarsi. As juveniles and adults, leucistics will
maintain yellow legs and feet and may have pale yellow or olive lores on the bill
(Mitchell 1994).
The trumpeter swan call is described as deep, resonant, loud, and trumpet‐like. Its call
has many social functions, such as alarm, excitement, territorial display, and defense. It
may call with its bill open or shut to produce slightly different sounds. In addition to the
characteristic calls, it will also hiss, peep, and gurgle. The cygnets will softly ‘pip’ with a
high‐pitched tone that will deepen into the adult tone at 6‐8 months of age. How vocal a
swan will be depends upon its social context, with incubating or brooding swans
remaining relatively quiet while non‐breeding swans or wintering flocks tend to be more
vocal (Mitchell 1994).
Species Habitat
During the breeding season, trumpeter swans select small ponds, lakes, or bays within larger lakes with
extensive beds of cattails, bulrush, sedges, and/or horsetail (Coffin and Pfanmuller, 1987). Coffin and
Pfanmuller also state that “muskrat houses and beaver lodges are frequently used for nesting
platforms.” They are known to protect large territories during the nesting period and are intolerant of
crowding by other species. They have been known to kill perceived competitors such as pelicans while
protecting breeding territories. Trumpeter swan nesting territories range from 6 to 150 acres in size.
They utilize large, shallow wetlands one to three feet deep with a diverse mix of emergent vegetation
and open water offer ideal habitat. Such locations support a rich variety of submerging (underwater)
plants used for food, such as sago pondweed and water milfoil (Wisconsin DNR website).
Species Distribution and Occurrences within the Study Area
Three populations of trumpeter swans are distributed across North America. The Pacific population,
which migrates between Alaska and Oregon, the Rocky Mountain population, which ranges between the
Yellowstone area and the northern Rockies, and the interior population, which is located in the upper
Midwest and northern Great Plains. The interior population, consisting of Minnesota, South Dakota,
Iowa, Wisconsin, Michigan, Ohio, and Ontario has largely been reintroduced since 1987 (Southwell,
2002b).
Minnesota’s flock now consists of 2,400 birds (DNR, 2009). CNF historic and recent records show 17
records on Forest Service lands and one within the Study Area.
Risk Factors
Risk factors include human disturbance, accidental shooting, powerline collision, and alteration of
hydrology to wetlands habitats (DNR, 2009).
4.2.1.10 Black‐Throated Blue Warbler (Dendroica caerulescens)
The black‐throated blue warbler is listed as a CNF RFSS and as DRM Sensitive.
July 2010 Species and Associated Habitat Page 4‐14