Naming a species a “least” this-or-that or a “lesser” such-and-such smacks a bit of disparagement. The bird exists only in relationship to a larger/greater/“better” bird. The Lesser Goldfinch’s comparator is its Spinus congener, the American Goldfinch. In this context, the Lesser Goldfinch comes up short in several ways. It measures ½” (10%) shorter and weighs 40% less. Its limited range covers western Texas, coastal California, and the Four Corners states; the American Goldfinch’s distribution stretches pretty much over the entire U.S. Even the Lesser’s plumage offers a toned-down version of the American Goldfinch: The male of the more western subspecies—the one common in our area—displays a black crown, a mostly olive-green back, and dull yellow underparts, in contrast to the flashy, gleaming yellow and jaunty black cap of the male American Goldfinch. So the thinking is clear: The Lesser does appear to be less than the American Goldfinch, in just about every way.
The Lesser Goldfinch is one of San Diego County’s most widespread birds. As a year-round resident and a habitat generalist, it takes advantage of any weedy area for foraging. Nesting birds need shrubs or trees for nest sites and water for drinking within an easy distance from the foraging habitat. Lessers maintain a rather strict vegetarian diet, even during breeding season: More than 98% of their diet consists of seeds, flowers, buds, and a few small fruits. (The remainder is made up of a few insects unfortunate enough to be on those seeds, flowers, buds, and fruits.) Lessers especially favor the seeds of the vast daisy (composite) family, such as thistle and wild sunflower. If you provide a feeder stocked with black nyger (a.k.a. thistle seed), you’ll likely become a favorite stopping spot of these little olive and black gems. And you’ll risk going broke stocking it with this ridiculously expensive seed. Most birds get ample moisture from their diets (e.g., from insects or fruit); however the dry nature of the Lesser’s seed-dominant diet makes it a frequent visitor to any water feature you might offer too.
Pairs begin to form in February, the first sign of the initiation of breeding season. Lesser Goldfinches defend small territories, and pairs often breed in loosely organized colonies. The female typically lays between three and five eggs. Incubation ranges from 12 to 15 days, and young remain in the nest for 11–15 days after hatching. Regardless of what the adults typically eat, most songbirds stuff their kids full of insects because the growing kids need lots of protein. But Lessers simply regurgitate a slurry of whatever they have been eating into the nestlings’ beaks. Luckily, because thistle seeds have a very high protein content (compared to many other seeds), nutrition doesn’t suffer. Upon fledging, the juveniles remain dependent on the adults for a week or so and then may forage as a jabbering, twittering cloud of olive, black, and yellow.
The Lesser Goldfinch’s scientific name—Spinus psaltria—finds its roots in Greek. Spinus derives from the Greek word for a linnet (a small European finch that depends on flax seed, from which linen is made). The species name psaltria refers to a female harp or lute player, in reference to a Lesser’s descending call note. Its common name has much more pedestrian origins: “gold,” referring to its yellow color; “finch,” from the Anglo-Saxon finc, that language’s name for finches in general; and “lesser,” since it’s the smallest of all North American goldfinches.
So there’s that “lesser” issue again. But in at least one way, the Lesser Goldfinch confirms the paradox of “less is more.” This tiny finch holds the record as the smallest avian mimic in North America. Interspersed with its downward “TEE-yeer” call note, you can identify a number of phrases picked up from other birds. In one study, more than 50% of an average Lesser Goldfinch’s song consisted of mimicked phrases. In our area, the song snippets most often incorporated included Western Bluebird, House Finch, Western Wood-pewee, and American Goldfinch. With an estimated average repertoire size of at least 70 borrowed phrases, the Lesser Goldfinch shows us that “less is more” rings true.