Pre-breeding food habits and condition of ruffed grouse and effects on reproduction in the central and southern Appalachians

Previous researchers have hypothesized that low ruffed grouse densities in the central and southern Appalachians may be related to nutritional constraints. Working as part of the Appalachian Cooperative Grouse Research Project (ACGRP), I investigated the pre-breeding food habits and body condition of 432 ruffed grouse from 9 states and explored relations between nutrition of breeding females and productivity in the central and southern Appalachians. The pre-breeding diet of ruffed grouse in the Appalachians differed substantially from grouse in more northern regions and was highly variable among and within sites and years. Grouse feeding on hard mast contained 71--79% greater fat reserves during the pre-breeding period than grouse feeding on alternate forages. I found evidence to suggest that pre-breeding females in poor condition may decrease reproductive output at the site-level via delayed nesting, smaller clutch size, and reduced chick survival. Chick survival to 5-weeks post-hatch on sites containing females with low fat reserves was 50% to 65% lower than on sites containing females with moderate or high fat levels. My findings support the hypothesis that nutrition and condition of breeding females influences the population dynamics of ruffed grouse in the central and southern Appalachians. Because substantial variation in nutritional ecology was evident among regions, land managers should formulate habitat management prescriptions that will fulfill the local nutritional needs of ruffed grouse