Body Condition and Nutrition of Snow Geese Wintering in Southeastern Texas

Abstract

The body condition and nutrition of wintering lesser snow geese (Chen caerulescens caerulescens) were studied in a rice-producing area of southeastern Texas during two winters (Oct-Mar), 1978-80. The diet of geese changed completely from rice (Oct-Nov) to sprouting green vegetation (Jan). The nutritional values of these diets were different and were accompanied by changes in gizzard weight and fat reserves. The quality and quantity of wintering-ground food resources apparently were not limiting factors that adversely affected the body condition of snow geese. Adult males (N = 195) and females (N = 192) maintained their energy reserves during the wintering period (except in Dec), and left in March in essentially the same body condition they were in when they arrived. Immature males (N = 174) and females (N = 142) increased (P < 0.05) their energy reserves during the wintering period. The rice-prairie wintering grounds provided all of the resources required by snow geese to meet their winter metabolic demands for body maintenance (adults) and growth (immatures). Adult snow geese leave the wintering grounds in March prior to making large increases in their overall energy reserves. J. WILDL. MANAGE. 49(4):1028-1037 The physiological condition of geese upon arrival on the breeding grounds plays an important role in determining annual productivity and reproductive success (Harvey 1971, Ankney 1974, Raveling 1979a). Adult females in poor condition (low fat and protein reserves) are predisposed to nest desertion (Harvey 1971), starvation during incubation (Ankney 1974:111), and increased nest predation due to increased feeding time away from the nest (Ankney 1977a, Ankney and MacInnes 1978:468). Harvey (1971) suggested that females in poor condition may have been unable to obtain sufficient food on the wintering grounds. Furthermore, Ryder (1970) hypothesized that clutch size in Arctic nesting geese evolved in relation to the amount of energy reserves accumulated by females before arriving on the breeding grounds. Studies by Ankney and MacI nes (1978) supported this theory. The depend nce of clutch size on stored reserves indicates that spring weight accumulation is of critical importance to geese (Raveling 1979a). Consequently, variations in food resources on the wintering grounds and spring migratory stopping points may be a proximal cause of annual variations in clutch size in geese (MacInnes et al. 1974, Ankney and MacInnes 1978, Cooper 1978:57, Raveling 1979a). The body condition of snow geese on one of their major wintering grounds, the rice-producing areas of Texas, is poorly documented. The objectives of this study were to measure changes in the body condition of snow geese wintering in a rice-producing area of southeastern Texas and relate changes in body condition to habitat and food resources. I Present address: P.O. Box 572, Columbus, TX 78934. This content downloaded from 157.55.39.158 on Fri, 18 Nov 2016 04:12:40 UTC All use subject to http://about.jstor.org/terms J. Wildl. Manage. 49(4):1985 WINTERING SNOW GEESE & Hobaugh 1029 Financial support for this research was provided by the Caesar Kleberg Res. Program in Wildl. Ecol. I wish to thank J. G. Teer, W. H. Kiel, Jr., and N. J. Silvy for their interest, assistance, and advice throughout this project. I also thank O. C. Jenkins for statistical advice. Special appreciation is extended to W. N. Lehrer for allowing me access to his property and to all the landowners who allowed me to collect geese. I thank H. D. and R. L. (deceased) Lobpries for their help and for the use of their facilities to examine geese. I am also grateful to the other commercial bird processors for their cooperation. I thank J. G. Teer, W. H. Kiel, Jr., N. J. Silvy, and C. D. Stutzenbaker for reviewing a draft of this manuscript. This is Texas Agric. Exp. Stn. Publ. 20582.