Wintering ecology of geese in the rice prairie area of southeast Texas

Abstract

The wintering ecology of 3 species of geese was studied in the rice prairie area of southeast Texas between October and April, 1978-79 and 1979-80. Data were gathered on numbers of geese, flock size, food availability, habitat use, nutrition, body condition, and cestode parasitism. A total of over 2.3 million geese was observed during 22 aerial counts made of the study area. Lesser snow geese (Anser caerulescens caerulescens) were the most numerous species during both wintering seasons (65-69%), followed by white-fronted geese (Anser albifrons) (19-21%) and Canada geese (Branta canadensis) (9-13%). Habitat use information was obtained from observations of 1.6 million snow geese, 483,000 white-fronted geese, and 260,000 Canada geese. Rice stubble was the most important habitat type to wintering snow and white-fronted geese. Nearly 60% of the snow geese and 54% of the white-fronted geese were seen in rice-stubble fields (14% of the study area). Canada geese preferred soybean fields. Foraging geese followed seasonal habitat-use patterns. Snow and white-fronted geese were found almost exclusively in rice fields as long as rice was readily available (Oct-Nov). By January, geese had shifted their diet to sprouting green vegetation which they obtained primarily from rice-stubble and plowed-ground fields. Occasionally, geese were seen in other habitat types as they spread out to take advantage of all food resources available to them. Adult snow and white-fronted geese were able to maintain their overall energy reserves during the wintering period (except in Dec). Neither adult males or females showed any significant (P < 0.05) differences between their arrival (Oct) and departure (Mar) mean body weights, fat reserves, or condition-index values. Adult geese left the wintering grounds prior to making large increases in their overall energy reserves. Immature snow geese significantly (P < 0.05) increased their overall energy reserves during the wintering period. This research concludes that geese wintering in the rice prairies of southeast Texas rely very little on their endogenous energy reserves to meet their daily energy needs. The number of snow geese that were parasitized by cestodes increased suddenly in March. Management implications are discussed.