On the wild side—August, 2012
by Tina Mitchell
Any morning from early June through August in our area, a tinkling, twittering jumble of notes may slice through the air, interspersed with a bell-like descending “tee-yeer.” As other birds wind down their singing—everyone instead busy finding food to stuff into hungry baby mouths—the Lesser Goldfinch begins singing to kick his breeding activities into high gear. As the smallest member of the North American genus Spinus, this species features 2 distinct subspecies. The males of both subspecies have stunning black foreheads, crowns, and wings. But the members of the eastern subspecies have entirely black backs (photo, left) and brilliant yellow underparts while those of the more western subspecies has mostly green backs and slightly dull yellow underparts (photo above, right). (Far less showy, the females of both display olive green upperparts and light olive-yellow underparts.) Colorado stands at the intersection of the ranges of these 2 subspecies, so we can see both of them.
Lesser Goldfinches associate much more frequently with pinyon/juniper woodlands than with any other specific habitat. However, across a wide variety of deciduous riparian (river) forest habitats (e.g., narrow- and broad-leaved cottonwoods), Lesser Goldfinches abound as well. Lessers maintain a pretty strict vegetarian diet: More than 98% of their diet consists of seeds, flowers, buds, and a few small fruits. (The remaining 2% is probably 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 thistle feeder, you’ll likely become a favorite stopping spot of these yellow gems, once they discover it.) Most birds get a good amount of 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 features you might offer too.
From their wintering grounds in the southwest U.S, Mexico, and Central America, Lesser Goldfinches arrive in Colorado in mid-May and begin nesting activities in June. As a result, they are among the latest-nesting species in our area. By early July, the female lays 4 or 5 eggs that hatch after 12 days. Both parents help to feed the kids, primarily through regurgitating seeds that they have ingested. The young fledge 11 – 14 days after hatching, remaining dependent on their parents for several weeks after leaving nest.
The Lesser Goldfinch’s scientific name—Spinus psaltria—has 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 its clear descending call note. Its common name has much more pedestrian origins: “lesser,” since it’s the smallest of all American goldfinches; “gold,” referring to its yellow color; and “finch,” from the Anglo-Saxon finc—that language’s name for finches in general.
This tiny finch exhibits a unique talent—it is the smallest avian mimic in North America. Interspersed with its downward “tee-yeer” call note, you may notice 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 commonly incorporated are copied from House Finches, Pine Siskins, and American Robins. With an estimated average repertoire size of at least 70 borrowed phrases, ain’t nothin’ “Lesser” about that!
To hear a sample of a Lesser’s song and call notes and to find links to photos, click here.