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. While they favor feeding in open forest canopies where cone seeds are abundant, they'll forage in habitats as diverse as deciduous forests and thickets, meadows, grasslands, weedy fields, roadsides, chaparral, and backyard gardens and lawns. They flock to backyard feeders offering small seeds. Mineral deposits can lure them to otherwise unattractive habitats like winter road beds that are salted to melt snow and ice. Back to top
As their name suggests, Pine Siskins have a fondness for the seeds of pines and other conifers like cedars, larch, hemlock, and spruce. They also feed on deciduous seeds like alder, birch, sweetgum, and maples. They eat the young buds of willows, elms, and maples, and the soft stems and leaves of weeds and even young garden vegetables. They'll glean the seeds of grasses, dandelions, chickweed, sunflowers, and ragweed. They forage for insects, spiders, and grubs from leaves and branch tips, and occasionally take insects from the air. Pine Siskins feed readily at backyard feeders, preferring smaller seeds without tough shells like thistle and oil sunflower, but they will scavenge fragments of larger seeds left by heavier-billed birds, and will occasionally eat suet. They also feed on mineral deposits, including ashes, road salt, and fresh cement. They have been seen drinking from sapwells drilled by sapsuckers.Back to top
The female loosely attaches the nest toward the end of a horizontal branch, by preference in the middle heights of a conifer. The spot is usually well concealed by foliage, often by another branch directly above it. Pine Siskins often nest in loose colonies where neighboring nests can be just a few trees away.
Over the course of 5 or 6 days, the female builds a shallow saucer of twigs, grasses, leaves, weed stems, rootlets, bark strips, and lichens, 2.5–6 inches across. The male, who stays close, may contribute nest material as well. The female lines the 1 to 2.5-inch inner cup (up to 2 inches deep) with fur, feathers, grass, moss, or thistle down. She may complete the nest several days before egg-laying. Nests are only loosely attached to branches and can be vulnerable to gusty winds.
|Clutch Size:||3-5 eggs|
|Number of Broods:||1-2 broods|
|Egg Length:||0.6-0.8 in (1.5-1.9 cm)|
|Egg Width:||0.4-0.6 in (1.1-1.4 cm)|
|Incubation Period:||13 days|
|Nestling Period:||13-17 days|
|Egg Description:||Pale greenish-blue with brown or reddish-brown spotting.|
|Condition at Hatching:||Helpless, weighing just over a gram, eyes closed, with dark gray down on head and back.|
Pine Siskins flit about in the topmost canopy of seed-bearing trees. They'll often cling upside down to branch tips to empty hanging cones of their seeds. Abundant seeds or tender shoots lure them to the ground to feed. Gregarious flocks are constantly atwitter with wheezy contact calls while feeding or during their undulating flight. Unusually convivial and unterritorial, they sometimes nest in loose colonies, continuing to forage in flocks away from the nests. Males sing from high perches and during circular courtship flights. Pairs may visit other pairs' nests before and after brooding. During brooding, the female stays on the nest and the male feeds her. Winter flocks and individuals can be aggressive around food sources, challenging competitors by lowering their heads, spreading their wings and tail, and making faint threatening call notes. Aggressive lunges are the next step and may result in fights that can carry competing siskins several meters into the air. Opportunistic Pine Siskins may forage close to heavier-beaked birds, gleaning fragments of larger seeds they can't crack themselves. And they'll hop on the downy seed heads of dandelions, trapping them on the ground for easy picking. Pine Siskins sometimes migrate in flocks of several thousand.Back to top
Pine Siskins are fairly common, but their numbers can be difficult to estimate due to the large and hard-to-predict movements they make each year. Partners in Flight estimates a total breeding population of 46 million, but numbers have declined over 2% per year for a cumulative decline of about 69% between 1966 and 2019. The Pine Siskin rates a 10 out of 20 on the Continental Concern Score and is considered a Common Bird in Steep Decline. Domestic cats, red squirrels, hawks, jays, and crows prey on adult birds or on their eggs or young. Dense flocks of Pine Siskins seem particularly vulnerable to outbreaks of salmonella transmitted at feeders (more on feeder maintenance). Studies have shown local impacts on their populations from DDT and related pesticides as well as from cyanide used in gold mining. Pine Siskins' fondness for mineral deposits can lure them onto dangerously busy roadways that have been salted to melt ice and snow. Loss of habitat from forest-clearing may be balanced by new, commercially planted coniferous forests, and by the Pine Siskin’s willingness to nest in shrubs and ornamental trees.Back to top
Dawson, William R. (2014). Pine Siskin (Spinus pinus), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.
Lutmerding, J. A. and A. S. Love. (2020). Longevity records of North American birds. Version 2020. Patuxent Wildlife Research Center, Bird Banding Laboratory 2020.
Partners in Flight. (2020). Avian Conservation Assessment Database, version 2020.
Sauer, J. R., D. K. Niven, J. E. Hines, D. J. Ziolkowski Jr., K. L. Pardieck, J. E. Fallon, and W. A. Link (2019). The North American Breeding Bird Survey, Results and Analysis 1966–2019. Version 2.07.2019. USGS Patuxent Wildlife Research Center, Laurel, MD, USA.
Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, NY, USA.