Clark's Nutcracker: a forester at heart

When we visited Manning Park a few weeks back, we saw a number of Clark's Nutcrackers. This is a distinctive, fairly large, member of the crow family (Corvidae), and in spots like Manning Park it is often seen around the park lodge, foraging amongst the Columbian Ground Squirrels that inhabit the open lawns, or up near the lookout. What's interesting about Clark's Nutcrackers is that they are very tied to pine trees as a food source, especially to two higher alpine 'white pine' species: whitebark pine (Pinus albicaulis) and limber pine (Pinus flexilis). The birds store pine seeds for later use, and as a result are the major dispersal agent for these two species. According to Wikipedia, "Clark's Nutcrackers each cache about 30,000 to 100,000 [pine seeds] each year in small, widely scattered caches usually under 2 to 3 cm of soil or gravelly substrate. Nutcrackers retrieve these seed caches during times of food scarcity and to feed their young. Cache sites selected by nutcrackers are often favorable for germination of seeds and survival of seedlings. Those caches not retrieved by time snow melts contribute to forest regenetation. Consequently,Whitebark Pine often grows in clumps of several trees, originating from a single cache of 2-15 or more seeds." Apparently the birds can find their seed cache with ease even after many months, and under a thick blanket of snow.

Limber pine is restricted in BC to a small region in the eastern part of the province, while whitebark pine has a much broader distribution (which more or less matches the breeding distribution of Clark's Nutcracker). However, Pinus albicaulis is a species in decline, a result of infections by white pine blister rust, an introduced fungal disease that is taking its toll on the species. It is also attacked by Mountain Pine beetle, a species that is devastating forests in BC. Clark's Nutcrackers do eat seeds from other pine trees as well as insects and berries, and even suet from feeders. Let's hope that this variaton in their diet means they have enough adaptability to survive the decline of their major food sources.

Clark's Nutcrackers have large strong bills that are used to open pine cones.

View a Canadian distribution map for Clark's Nutcracker.
View the Breeding Bird Atlas of BC map for Clark's Nutcracker.
View photos of whitebark pine from the E-Flora BC photo gallery.
View photos of limber pine from the E-Flora BC photo gallery.
View photos of Clark's Nutcracker on E-Fauna BC.

Whitebark pine and limber pine are very similar in appearance. The E-Flora atlas pages for these species indicate how to separate them.