24.

White-footed Vole

Arborimus albipes

French: Phénacomys a pieds blancs / German: WeiRfuR-Baumwihimaus / Spanish: Topillo de pies blancos

Taxonomy. Phenacomys albipes Merriam, 1901, “Redwoods, near Arcata, Humboldt Bay [Humboldt Co.], California,” USA .

This species is monotypic.

Distribution. NW USA, from Columbia River in N Oregon S along Oregon Coast Range to Humboldt County, California, and W slope of Cascade Range in Oregon; only three of more than 40 known sites acrossits distribution are in California and the rest in Oregon.

Descriptive notes. Head—body 103-110 mm, tail 62-71 mm, ear 11-13 mm, hindfoot 19-21 mm. No specific data are available for body weight. No geographical variation in morphology has been described in White-footed Voles—one of the smaller voles in North America. Dorsum has dark bluish gray-tipped hair, with dark brown or black that lightens on sides to gray or pinkish buff on venter. Tail is bicolored, dark on top and light below, and relatively long (more than 50% of head-body length). Feet are grayish. Reentrant angles are much deeper on lingualsides of lower molars than on labial sides. There are three loops of enamel on lingual sides of M”.

Habitat. Small, alder-lined streams in redwood forests, especially when small clearings that support herbaceous growth are present, from sea level to elevations of ¢.1100 m (most records coastal). White-footed Voles have been found in many age-classes and types of forests. Whether or not it is common within it distribution is unknown, but it sometimes is noted as the rarest North American vole.

Food and Feeding. White-footed Voles are thought to eat a wide range of herbaceous plants and in the last few decades, more has been learned aboutits natural history and food habits due to intensive study in the Cascade Range of southern Oregon. Their propensity to eat pollen of hazel ( Corylus cornuta, Betulaceae) in unopened catkins has been noted. Fungi are common foods, especially spores of the genus Rhizopogon. Other fungi consumed are from Hydnotrya, Hysterangium, and Melanogaster . Roots have also been reported in their diet. Common plants in the diet include shrubs such as Cascade Oregon grape ( Berberis nervosa, Berberidaceae) and thimbleberry ( Rubus parviflorus, Rosaceae) and forbs such as white clover ( Trifolium repens, Fabaceae) and wood groundsel ( Senecio sylvaticus, Asteraceae).

Breeding. White-footed Voles breed year-round, and litters most commonly have three young (range 2-4). Gestation is ¢.28 days, and weaning lasts up to 35 days.

Activity patterns. The White-footed Vole is nocturnal, reportedly terrestrial, and burrows, but a semi-arboreal existence has been suggested due to strong association with hazel and alder ( Alnus rubra, Betulaceae).

Movements, Home range and Social organization. No information.

Status and Conservation. Classified as Least Concern on The IUCN Red List.

Bibliography. Bellinger et al. (2005), Bradley, Ammerman et al. (2014), Cassola (2016f), Hayes (1996), Johnson & George (1991), Manning et al. (2003), Maseret al. (1981), Musser & Carleton (2005), Verts & Carraway (1988, 1995).