Every fall researchers gather data throughout North America to assess the availability of winter food supplies for bird species. This data mainly focuses on finch species and can help predict bird movements throughout the winter months. For example, an abundance of spruce crops such as pine cones can provide an ample winter food supply for the resident finches in that area so they are not likely to wander very far in search of food. The opposite is also true. In areas of widespread poor or patchy food supplies the birds might wander into other regions when existing foods are depleted. This research can help predict what are called “winter finch irruptions”. If North America’s western northern forests have not produced an ample supply of winter foods some species may wander into areas of New Mexico where they are not normally seen in search of seeds, nuts and fruits.

The Pine Siskin is a finch species that lives in the northern forests and upper elevations in the western states including New Mexico. When I lived in the upper mid-west it was uncommon to see Pine Siskins, but one winter a large flock of these unfamiliar birds swarmed my bird feeders and gorged on sunflower chips and nyjer seed. They were there for two days and left as suddenly as they appeared. This was an irruption. In New Mexico this species is seen mainly in the mountains, but if food supplies dwindle it is not uncommon to see them in lower elevations in the winter months.

Evening Grosbeaks are a fairly large, striking bird at 8” long with a yellow body, white wing patch, yellow eyebrow and an extremely thick, stubby bill. The females are less colorful with a pale greenish body. This beautiful finch species is found in the northern forests and upper elevations in the western US. Evening Grosbeaks are more commonly seen in northern New Mexico in winter months, but if there is unusually heavy snow pack causing a disruption of food availability they can wander as far south as Albuquerque. A number of years ago there was such an irruption and I was lucky enough to have dozens of Evening Grosbeaks at my Albuquerque bird feeder eating black-oil sunflower seed for about 3 weeks.

These are just two examples of winter finch irruptive species. Be sure to keep an eye out for other exciting birds that may visit your area this winter.

Mary Schmauss is the owner of Wild Birds Unlimited in Albuquerque. A lifelong birder and author of For the Birds: A Month-by-Month Guide to Attracting Birds to your Backyard.