The Pine Siskin is a small finch widespread in North America. In winter it moves widely in response to seed crops.
It has brown streaks, yellow markings on the wings and tail, and a slender bill.
Pine Siskins are nomadic North American finches whose movements vary among years. Researchers housed wintering birds indoors and compared a group exposed to naturally lengthening spring days with a group kept on the short day length around the winter solstice. In Los Angeles, they measured changes in body condition and activity associated with migratory preparation.
Birds experiencing spring-like day lengths increased fat deposits and nocturnal migratory restlessness; birds kept on short days did not show the same pattern. Body condition, flight-muscle size, and night activity changed around late March in the experiment year. The results show that day length can help initiate seasonal migratory preparation in this nomadic species.
An extinction-risk assessment has not been added yet.
In the indoor experiment, fat deposits and nocturnal activity increased under lengthening spring days but not under the short-day schedule.