Grizzly bear and gray wolf are listed as species of greatest concern in the HCP. Both are extremely rare in Washington and neither has been documented in the watershed. There is a good chance, however, that grizzlies may pass through city ownership because a few live in the north Cascades and they have occasionally been sighted to the south of the watershed. If populations increase in the future, the watershed may provide undisturbed habitat required by these wide-ranging large carnivores.

Although marten have not been documented in the watershed, they are very likely present.

Four species of smaller forest carnivores are considered species of concern in the HCP: fisher, marten, wolverine, and lynx. None of these species have been documented in the watershed since the 1960s, but it is likely that marten are living in the watershed because they have been found just four miles to the east. A forest carnivore study using remote camera traps is currently underway to determine if either fisher or marten are present. Wolverine may also be captured by these cameras because their tracks were found just six miles east of the watershed in 2006. All of these small forest carnivores favor undisturbed areas of mature and old-growth forest. View more information on the forest carnivore study on Seattle Public Utilities Biodiversity website.

There are 11 species of forest bats that are also considered species of concern in the HCP. Forest bats roost in hollow trees, snags, foliage, or under bark of large old trees. Old-growth forest provides optimal habitat for these small mammals because of the large number of big snags and the thick bark with many crevices found on giant old trees. During the night, bats forage in gaps within the forest, as well as over wetlands and open water, eating huge numbers of insects. A single bat can eat up to 2,000 insects each night. Monitoring and protecting existing old-growth forest, as well as enhancing forest habitat in younger forest by creating snags for roosting and canopy gaps for foraging should ensure these bats continue to live and breed in the watershed.