The siskin’s heavy streaking also makes it resemble a female house finch, but note the siskin’s smaller, finer bill. The pine siskin is 5 inches in length. As such, when it comes to nesting, the Pine Siskin prefers to build its nest on a horizontal branch of a coniferous tree, far from the trunk. The nest is shaped like a saucer and is made up of grass, rootlets, and twigs. Breeding birds flock together to forage. Pine Siskins can temporarily store seeds totaling as much as 10% of their body mass in a part of their esophagus called the crop. The nest is made of grasses, twigs, rootlets, bark strips, and lichens lined with feathers, fur, and rootlets. Pine Siskins are monogamous, and pairs form within winter flocks. They are often overlooked when mixed in with winter flocks of American goldfinches, which are drab yellow (but not streaky) in nonbreeding plumage. The Pine Siskin is gregarious even in the breeding season. The nest is defended against other Pine Siskins primarily during egg laying and incubation.
The nest is further insulated with fur, moss and other thick plants. After nesting in the conifer woods, Pine Siskins move out into semi-open country, where they roam in twittering flocks. They nest in loose colonies, and pairs may visit one another's nests. They may nest in loose colonies or in isolated pairs, and their breeding activity is more closely tied to the abundance of food than to season. The nest is highly insulated, and the female remains on the nest continuously, fed by the male throughout brooding. Pine Siskins generally nest in open coniferous or mixed forests, but also inhabit parks, cemeteries, and suburban woodlands, where they breed in ornamental conifers or deciduous trees. Nests are well hidden, on a horizontal branch well out from the trunk of a conifer tree. Feeders for Siskins and Finches To forage on a vast field, a group of pine siskins often builds up a temporary colony over the field. Pine Siskins protect their eggs from cold damage, too. The female makes a hidden cup-shaped nest with twigs, rootlets, leaves and bark strips within 5-6 days. They often descend on fields of thistles or wild sunflowers, where they cling to the dried flower heads, eating seeds.
Placed in a tree branch (usually a conifer) 3 to 50 feet above the ground. The female bird chooses the location of the nest as well as builds the nest herself.