Off-highway vehicle trail impacts on breeding songbirds in northeastern California

Rapid growth in off-highway vehicle (OHV) use in North America leads to concerns about potential impacts on wildlife populations. We studied the relationship between distance to active OHV trail and songbird nesting success and abundance in northeastern California, USA, from 2002 to 2004. We found evidence of greater nest desertion and abandonment and reduced predation on shrub nests < 100 to from OHV trails than at nests > 100 in from OHV trails. Two of 18 species studied were less abundant at sites on trails than at sites 250 in from trails, and no species were more abundant on trails. Management of OHV trail development should consider possible negative impacts on nesting success and abundance of breeding birds.