On another walk around the frozen suburban lake, we came across the carcass of a ring-billed gull. Recognizable only by a wing and head, much of the victim was scattered along and near the snowy trail. Since there was no blood on the snow, I assumed that the gull had died before its dismemberment and that it had likely been brought to the trail from the site of its demise.
Predators of gulls include hawks, falcons, owls, coyotes and fox, among less common hunters. While no clues were evident on the trampled path (i.e. no wing marks or specific tracks in the snow), the vigorous destruction of the carcass suggested the work of a fox or coyote. Indeed, further down the trail, fox tracks led up from the frozen lake, indicating that the killer may have ambushed the gull as it slept on the ice (or merely nabbed its carcass post-mortem).
Winter is the culling season and predators enjoy a distinct advantage. Weakened by a lack of food and the stress of winter weather, prey animals are easier to catch or simply provide freeze-dried carrion for carnivores and scavengers. Of course, the young, old and sick are most susceptible to predation or winter kill, leaving a healthy, vigorous and hardy population to propagate the species when spring finally arrives.