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Hemlock Woolly Adelgid's Impact on Winter Bird Communities (Stone Valley Forest)

Infested Eastern Hemlock Branch (Photo courtesy of Dan Hinnebusch)

Infested Eastern Hemlock Branch (Photo courtesy of Dan Hinnebusch)

Hemlock woolly adelgids (Adelges tsugae) are invasive, aphid-like parasites that feed selectively on the ray parenchyma of eastern hemlock (Tsuga canadensis) twigs. Hemlock is an ecologically important tree that grows throughout the eastern United States and southeastern Canada. This insect has been spreading across the range of the eastern hemlock, causing widespread destruction of many stands that were once composed predominantly of hemlock. Infestation has recently been detected in Stone Valley Forest, of which 7.3% of the area is covered in hemlock or hemlock-mixed hardwood stands.

Eastern hemlock is an important tree for many bird species found in the Stone Valley Forest, both during the breeding season and through winter months. Little research has focused on the effects of hemlock loss on winter bird communities. Birds of particular interest in this study include red-breasted nuthatch (Sitta canadensis), white-breasted nuthatch (Sitta carolinensis), brown creeper (Certhia americana), and golden-crowned kinglet (Regulus satrapa).

Because of the early stage of infestation, Stone Valley Forest presents an excellent opportunity to monitor changes in the winter bird community from initial infestation by hemlock woolly adelgid to the expected loss of eastern hemlock as a dominant tree in the forest.

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