American Goldfinch

Photo by Stan Tekiela

by Stan Tekiela
© NatureSmart

October 16, 2023

The vast majority of native bird nesting takes place in spring, right after the trees green up and the flowers start to bloom. The spring nesting season feels like a frantic rush to quickly build a nest, lay, and incubate eggs and feed the resulting chicks. Each species of bird approaches nesting slightly differently but ultimately with the same goal in the end, successfully passing on their genes within the fledging baby birds.

However, there are some species who don’t follow the early nesting playbook for reproduction. The American Goldfinch (Spinus tristis) is a great example of this alternate nesting behavior. Weeks after most young birds have left the nest and the adults are chasing after the young to feed them, the American Goldfinch is just starting to work on building a nest and laying eggs.

I was fortunate enough to recently find an American Goldfinch nest that was in a location to observe and capture a few images while not disturbing their natural nesting behavior safely and respectfully. Located along a driveway and down a small hill, the nest was slightly below eye-level when I parked my truck. This allowed me to stay inside my vehicle and use a very long lens to watch, learn and capture natural nesting behaviors.

It is not known why American Goldfinch nests so late in the season. It may be related to the ripening of thistle seed, which makes up a large portion of their diet. The extra food makes feeding themselves and their offspring much easier and perhaps leads to more babies leaving the nest. In addition to the abundant food, they also use the soft silky downy material attached to the thistle seed to line the inner cup of their nest. They also use silky material from Milkweed and Cattail. Again, an abundant nesting material makes it easier to construct the nest.

Male Goldfinch set up a territory and begin to make elaborate courtship flights while singing a loud clear song. His flight is often described as a roller coaster ride because his flight goes up and down in an undulating pattern. Closer to the ground he often flies in a zig-zag pattern from tree to tree to attract a female.

It is the female who constructs the nest often on the thin branches of a small tree or shrub. It takes her less than a week to fully construct the nest. Some males will bring construction material to the female, but she does all the work. She will lay four to six eggs over the next week before she sits down and starts to incubate.

Chicks hatch 12-14 days after incubation starts. The young are hatched naked, with their eyes still sealed shut and are completely helpless. The adult male collects food and brings it to the female who in turn feeds the newly hatched young. One of the things that makes these Goldfinch unusual is the fact they feed their young mostly seeds and very few insects. Most springtime baby birds are fed a high protein diet of insects.

There is very little nest parasitism by Brown-headed Cowbirds because it is believed the Goldfinch nests are too late in the year for the cowbirds and the survival rate of the cowbird offspring is very low in the Goldfinch nest because of the mostly seed diet.

The American Goldfinch is one of the strictest vegetarians in the bird world. Which is to say they don’t eat the number of insects like most smaller birds. They are considered granivorous birds, who only occasionally eat insects. They concentrate their food gathering efforts on a narrow variety of plants, and often these are considered weedy plants such as thistle, dandelion, ragweed, and other less desirable plants. They also consume fresh tree buds along with a wide variety of ripened fruit. Watching the American Goldfinch feeding at this time of year is fun. It often hangs upside down from seedheads while popping seed after seed out and consumes right on the spot.

Sitting in my truck with my lens poked out the driver window, I see the male flying to the nest where the female sits on the newly hatched young. He is singing his loud clear song as he approaches, and the female immediately starts to quiver her wings and open her mouth even before he arrives at the edge of the nest. When he does, the male feeds the female regurgitated slurry of seeds. He departs and in turn she feeds the young baby birds with the freshly delivered food. This is an amazing and very different strategy in bird reproduction. Until next time…

Stan Tekiela is an author / naturalist and wildlife photographer who travels the U.S. to study and capture images of wildlife. He can be followed at www.instagram.com, www.facebook.com. He can be contacted at his website www.naturesmart.com.