2 - The Ecology and Evolution of Spatial Memory in Corvids of the Southwestern USA: The Perplexing Pinyon Jay

Abstract

This chapter discusses the exploitation of pine seeds by species of the family corvidae. The seed of the pinyon pineiis contains up to 18% protein and 60% fat. This is a powerful fuel to sustain these birds through the long, cold, and unproductive winter. The behavior of nutcrackers and Pinyon Jays is immediately altered at the sight of these cones or seeds as they abruptly stop all other behaviors and begin harvesting. These birds spend a vast amount of time and energy in harvesting, transporting, and caching these seeds. This dramatic change in behavior is a clue that these pine seeds are of special biological significance, at least to some of these corvids. Eurasian Nutcrackers that had dispersed thousands of kilometers into Germany, owing to lack of pine seeds in Siberia, immediately began harvesting, eating, and caching seeds when presented with them. The pine tree also has an interesting role in this ecological play. In one out of every five to six years, the pinyon pines make it easy for the jays and nutcrackers to harvest their seeds. The seeds are extracted easily as the pine cones have no sharp spines on their relatively short cone scales to deter extraction.