SCHIESS: Dirty birds invade backyards

The fighting over the nyger seed sack in my backyard was intense. House finch, Pine siskins and American goldfinch were battling over the food as the snow was falling.

The goldfinches were not in their striking bright yellow and black summer coat, but they appeared a dirty white or pale yellow edged in black. Many beginning birders don’t recognize them like this.

The American Goldfinch molts twice a year which is different than most finches, which only change their feathers once. During the fall goldfinch gradually shed all of their coats with the male’s brilliant yellow replaced by a light olive or a “dirty white.”

As they molt patches of yellow can be seen in the newly grown drab feathers. These drab feathers help the small songbirds camouflage during the winter months as they hide from marauding Sharp-shinned hawks and merlins as they troll the feeding stations.

In the spring, both sexes lose all of their fall growth except for the tail and wing feathers that are molted only once. These are black in the males and a dark olive in the females and are only lost in the fall.

The brilliant yellow of the male is necessary to attract a mate. The brighter the yellow the more attractive it is to females. Aerial displays by males can be interesting to watch as they attempt to attract a mate.

Abundant winter and spring food is critical for goldfinch. Thus they will battle all other birds coming to their favorite feeding spot, as their color comes from carotenoid pigments contained in the food consumed during the winter and early spring. The beak also changes from a pink to a brilliant orange in both genders as their color intensifies.

Goldfinches usually only migrate when forced because of extremely cold weather or lack of food. Then they migrate only a short distance where shelter and food can be found. Once a feeding program is started in your backyard, it is critical to continue during the winter so these birds will have a consistent source of food.

Nyger, black oil sunflower seeds and white millet are the favorite food for these birds. Birders putting out food in the Upper Snake River Valley will see them visit in a very short time. Once a feeder is found somehow they communicate to others and many will show up along with other songbirds wintering nearby.

Natural food for these birds are weed and thistle seeds and the clearing of large areas of forests has helped the American Goldfinch to increase in numbers. With the clearing of conifers, seed producing plants abound allowing these beautiful bird populations to grow.

Usually not an aggressive bird, goldfinches are very social and will stay in large loose groups. Only during breeding, nesting and near feeders will they become aggressive with each other or other species. Males will show aggressiveness only to other males and females to females.

Their voice is almost a soft whistle that fits their social demeanor and physical beauty and softness. But you will know when they show up at a feeder as their chatter is unmistakable.

Want some fun birds around your yard? Put out a few bird feeders with thistle and sunflower seeds and they will come quickly. Watching them battle over a feed sack is fun on the cold winter days.