Hair Collection

High-quality hair samples allow us to identify both the species (e.g., black bear) and individual (e.g., black bear “A” versus black bear “B”) of origin. Once individuals have been identified via hair samples, the DNA of each individual can be further analyzed to provide detailed information about relatedness between individuals—a critical component of our landscape genetic study.

Map showing the Highway 20 study area, 2500 ha sample units, and a call-out of a single sample unit with hypothetical locations of bear corrals and marten hair-collection cubbies.

Our survey design is based on hexagonal sample units projected across the entire North Cascades Ecosystem. Each hexagon represents 2500 ha, an area slightly smaller than the average size of a female black bear home range in this region.

Components and layout of a standard barbed-wire bear hair corral, showing (a) the debris pile treated with scent lure, and (d) the coil of excess barbed wire (items b and c are not used in our protocol). Wire is deployed at a height of 45–50 cm in our study. Note that barbs are numbered sequentially beginning at one of the trees. Credit: Stephen Harrison, from Noninvasive Survey Methods for Carnivores (2008).

For bears, we optimally deploy two barbed-wire corrals within each sample unit surveyed, and space them as far apart as possible (e.g., ≥3 km) while maintaining a distance of ~1 km or more from the edge of the unit. Corrals comprise a single strand of barbed-wire stretched around four or more trees at a height of 45–50 cm, with woody debris piled in the center and treated with one liter of liquid scent lure (i.e., cattle blood and fish).

A black bear visits a barbed-wire corral.

Researcher Robert Long treats woody debris pile with scent lure. Credit: Paula MacKay

Corrals are revisited at ~14 days and (a) removed if a sufficient sample is present or (b) re-baited and left for another 14 days if no sample is present.

In the field, hair samples are immediately placed in small coin envelopes and stored in plastic containers with desiccant.

Bear hairs are removed from barbed-wire and placed in a coin envelope. Credit: Paula MacKay

Bear hairs are removed from barbed-wire and placed in a coin envelope. Credit: Paula MacKay

For martens, we deploy 3–5 tree-mounted hair snares within each sample unit surveyed, spacing devices at approximately 500 m and targeting suitable marten habitat (i.e., mature forest) whenever possible. Hair-snagging devices (i.e., gun-cleaning brushes) are attached to the tree-mounted enclosure, which is baited with chicken and scent lure.

Researcher James Begley deploys a tree-mounted marten cubby. Credit: Ann Winters

A marten visits a hair-sampling station.

A marten interacts with gun-cleaning brushes on a tree-mounted cubby.

Marten hairs on a gun-cleaning brush. Credit: Paula MacKay