These birds are very gregarious and often seen in mixed flocks with Lawrence's Goldfinches.
The Lesser Goldfinch does not mind nesting in deciduous trees. They also nest in shrubs. They like to build their nests at the end of branches.
Like most finches the Lesser Goldfinch does not feed entirely on seeds. They also eat an occasional arthropods.
The Lesser Goldfinch can be attracted to your garden by a birdbath. They also like seeds. See diet.
The Lesser Goldfinch feeds mainly on seeds but they can also be found feeding on fruits, buds and insects. They do not use trees as much as the Lawrence's and American goldfinches. However, they will eat buds, flowers, and acorns from Oak trees. They also eat the fruits from Willow, Salix spp., Alder, Alnus spp, and Birch, Betula spp. The Lesser Goldfinch can often be seen in the chaparral eating Chamise and Woolly Blue-curls seeds. They also like to feed on Asteraceae. Some other plants used are Miner's lettuce, Red Maids, Fiddle neck, Amsinckia spp. and Dove weed, Eremocarpus setigerus, Night Shades, Solanum spp, Sage Salvia spp, Catch-fly, Silene spp. Tar weed Hemizonia spp.,
A large portion of the diet consists of weeds including Bromus spp., Centuria spp., and Erodium spp. The Insects eaten include aphids and caterpillars. These are eaten in the summer.