Forestry Practices and the Risk of Bird Nest Predation in a Boreal Coniferous Forest

Abstract

Reconciling tree harvesting with the maintenance of forest bird populations is a major concern of integrated management. Because bird nest predation causes >50% of the nest losses in passerines and is known to vary according to habitat characteristics, we explored some aspects of avian nest predation in relation to forestry practices in a boreal coniferous landscape managed primarily for timber production in Québec. Using artificial tree and ground nests with Common Quail (Coturnix coturnix) and plasticine eggs, we compared the risk of nest predation (1) in experimental riparian forest strips of different widths (20-m, 40-m, and 60-m unthinned strips; >300-m control strips; and 20-m thinned strips) and (2) in clearcuts experimentally subjected to different regeneration practices (plantations with chemical and mechanical weeding, and naturally regenerated clearcuts) between 1992 and 1995. The risk of ground nest predation was lower in naturally regenerated clearcuts (5% daily probability of predation) than in control forest strips (27%). We found no evidence that chemical and mechanical weeding affected the risk of nest predation in clearcuts. In forest strips, the predation risk was higher in forest strips 40–60 m wide than in 20-m and control strips. Birds accounted for 13% of predation signs, whereas red squirrels (Tamiasciurus hudsonicus) were the dominant mammalian predators, accounting for 36% of the total predation (n = 201 nests preyed upon). In our region, the low predation rates (30% for 24 real nests) and the absence of generalist foragers such as crows, raccoons, and skunks could be attributed to the near absence of human occupation in comparison to forest-dominated landscapes in Europe and northeastern United States.