Are Moose Creating Bird Habitat?

ALRF staff and a group of UNBC students were visiting a   teaching site in a shelterwood harvest  treatment in late August when someone noticed a bird nest located in a short but very branchy birch tree. The site has been actively browsed by moose ever since the 18 ha block was harvested in winter 1994/95. The browse in this area was so extensive that the moose  were basically controlling the brush, making room for the planted spruce to  grow in the understory.

We know from a recent pilot study at  ALRF  that when moose browse the new  shoots  off  birch saplings,  the tree responds by sprouting more shoots, which encourages more browsing, which promotes more shoot growth, and so on, resulting in a very unusual  tree morphology or shape.

Apparently some types of nesting birds also find this moose/birch browsing and growing cycle very beneficial as well! According to Plants of Northern British Columbia (MacKinnon, Pojar & Coupe), the lichen species  used to construct this nest indicate either warbler  or vireo bird species.

 

Located about 1m off the ground, a bird's nest was tucked in between the multple stems of this birch sapling. The tree had been impacted by several seasons of moose browse.
The nest was roughly 10 cm in diameter and was assembled with small sticks and horsehair lichen (Bryoria species) and common witch's hair lichen (Alectoria species).