Extension Wildlife Research

facebook logoThe effects of exotic shrubs on caterpillar abundance and breeding success of declining songbirds 

New Extension Research

In spring 2012, researchers from UNH Cooperative Extension and UNH Department of Natural Resources and the Environment, led by Associate Extension Professor of Wildlife Matt Tarr, will begin research to examine how exotic shrubs influence habitat for shrubland-nesting birds.

Researchers will study the relationship between caterpillars, exotic/invasive shrubs, and the breeding success of birds that use shrubland habitats.  This study will be conducted on shrubby powerline rights-of-way in southeastern New Hampshire. Powerlines represent some of the largest and best remaining examples of shrubland habitat in this part of New England.

Why study exotic shrubs and caterpillars?
Caterpillars are an important food source for many shrubland birds. These birds rely on caterpillars to feed their nestlings during the breeding season.

Many caterpillars have evolved to eat the leaves from only certain native shrubs. Since exotic shrubs (such as glossy buckthorn and autumn olive) have only recently been introduced to the United States, they support fewer caterpillars than native shrubs (such as dogwoods and viburnums). UNH researchers predict that birds will have better breeding success (i.e. produce more young) in shrublands that have more native shrubs than exotic shrubs.

This study will focus on the common yellowthroat, a species of bird that breeds in shrubby thickets and uses caterpillars to feed its nestlings. This species is one of the most common birds in New England shrublands. However, populations of common yellowthroats have been declining in recent decades, along with those of many other Neotropical migrants that breed in shrublands.


NH Fish and GAme

PSNH logoThis project is made possible by grants from Public Service of New Hampshire, the New Hampshire Fish and Game Department, and theAmerican Wildlife Conservation Foundation.