Dames & Moore, 1999 - USDA Forest Service

- Mink
Mink are carnivores which feed, in order of importance. on mammals, fish and amphibians. birds. reptiles
and invertebrates. Population density depends upon available cover and food, but typically ranges from
0.01 to 0.1 mink per ha Mink home range depends largely upon food abundance but ranges from 7.8 to
20.4 ha. in heavily vegetated and sparsely vegetated habitats, respectively (Mitchell, 1961). Home ranges
are usually aligned with waterways and, in Idaho, mink were never observed more than 100 m from water
(Melquist et al., 1981). Adult male mink weigh about 1 kg and consume about 0.069 kg food/kg body
weight per day, and ingest about 0.099 Lkg body weight per day (EPA, 1993). In Michigan. Sealander
(1943) reported that small mammals comprised about 64 percent of the diet.
Metals data in small mammals have not been collected for the Holden Mine site. Therefore, the algorithms
provided by, Sample ei al. (1998) were used to estimate the secondary exposure minks acquire through
consumption of small insectivorous, omnivorous, and hehivorous small mammals (Table 7.2.3-1 0).
These equations were then used to estimate small animal concentrations at the UCL of Holden Mine soils
(Table 7.2.3-6) and the doses to mink (Table 7.2.3-14).
Duskv Shrew
The dusky shrew (Sorex vagrans 0bscw-u) is a carnivore which feeds largely on earthworms, insects, slugs
and snails (EPA, 1993). They have forage ranges of about 0.03 to 2.2 ha, depending on population density.
Shrews have very high metabolic rates and Winter mortality may range up to 90 percent. Dusky shrews
weigh about 0.022 kg and consume about 0.56 kg foodkg body weight per day and drinks about 0.22 Ukg
body weight per day. Since there are no data or models to estimate metals concentrations in insects, slugs.
or snails, it was assumed that the shrew diet is composed 100 percent of earthworms. The equations in
Sample et al. (1998) were used to estimate the metals concentrations in earthworms (Table 7.2.3-6) and
doses to the shrew (Table 7.2.3- 15).
Red-tailed Hawk
The red-tailed hawk is a carnivore which feeds largely on terrestrial rodents (EPA, 1993). Adult male red-
tailed hawks weigh about 1.2 kg and consume about 0.049 kg foodkg body weight per day and ingest about
0.056 Ukg body weight per day of water. In Oregon, Janes (1 984) reported that small mammals comprised
about 76.1 percent of the diet, with the remaining percentage composed of birds and reptiles. Doses for red-
tailed hawk (Table 7.2.3-16) were estimated using the small mammal body burdens developed for the mink,
above.
American Robin
The Arnerican robin is a common omnivore which feeds largely on fruits, ground-dwelling invertebrates,
and foliage-dwelling insects (EOA, 1993). Preceding the breeding season, about 90 percent of the diet
consists of invertebrates. Robins weigh about 0.078 kg and consume about 0.129 kg foodkg body weight
per day and drink about 0.14 Lkg body weight per day. The equations in Sample et al. (1998) were used to
estimate the metals concentrations in earthworms and the doses to the robin (Table 7.2.3-1 7).
G : ~ ~ W ) 5 ~ \ h o ~ 2 \ n i 7 4 4 Q c 7-60
17693-005419Uuly 27,1999;s: 16 P MDM FINAL RI REPORT