Purple finches are medium-sized finches that measure 15.2 cm in length, weigh 25 g, and have a 25.4 cm wingspan. Their bills are conical, pointed, and well-adapted for cracking open seeds. Males have red on their heads, backs, throats, breast, flanks, and rumps. Wing and tail feathers are brown, but may also be tinted red. Bellies and undertail coverts are unmarked white. Females are overall brown, and have a bold brown and white pattern on their heads. Their crowns are brown and are bordered by thick, white eyebrow stripes. A brown patch extends from their eye down to cover their ears. Below this patch, there is a thick, white mustache stripe followed by a dark brown malar stripe. Throats are white, and the breast features short, brown streaks that extend into the belly and flanks. As in the males, females' bellies and undertail coverts are white. Their backs are streaked with two tones of brown. Like many finches, purple finches have deeply notched tails that are visible in flight.
Juveniles of both sexes are nearly identical to adult females, and males may not develop full adult red plumage until after their first year.
This species is often confused with house finches. Where purple finch males are red nearly all over their bodies, house finches have less extensive red coloration that is concentrated on the crown, throat, breast and rump. It is often said that purple finch males look as though they have been dunked in raspberry jam. Regardless, there is significant variation in coloration among individuals and this is not always a reliable identification characteristic. The most distinguishing features are the flanks: house finches have brown-streaked flanks, whereas purple finches have reddish flanks. Females are also difficult to distinguish, but there are slight differences in coloration. Female purple finches have relatively bold, brown and white head patterns while female house finches have plain, brown heads. The brown streaks on the breast and flanks are blurry and grayish on house finches versus clear, brown streaks against a white background for purple finches. For both sexes, the bill shape may also help to identify the species. For purple finches, the bills appear straight and pointed, whereas house finches have bills that are curved and thus appear more stocky and rounded. (Sibley, 2000; Wootton, 1996)
Purple finches are found in North America, including the United States, Canada and a small portion of Mexico. Purple finches are a migratory species, meaning they spend parts of the year in different regions. During the spring and summer months, this species breeds across the southern half of Canada and may be found in every province except Nunavut. In central portions of their range, purple finches both breed and over-winter. This year-round range includes Nova Scotia, Canada and the east coast and New England regions of the United States (US) from Maine to Pennsylvania, as well as portions of Michigan and Wisconsin. In early fall, purple finches migrate south to spend the winter across the eastern half of the US. Some finches that live on the east coast may migrate further inland or into Baja California, Mexico. (Sibley, 2000; Wootton, 1996)
Purple finches inhabit both forested and urban habitats. They prefer to breed within or at the edge of open coniferous or mixed coniferous-deciduous forests. Other breeding habitats include urban parks, orchards, hedgerows, deciduous forests, or pastures with several suitable trees or shrubs. Studies have shown that this species actually responds positively to forest patches with a large amount of edge. During the winter, purple finches are considered habitat generalists and will inhabit most any area with ample food resources.
Historically this species has adapted well to human development and was an abundant resident in urban parks, gardens, or streets lined with ornamental trees. In recent decades, introduced house finches have out-competed native purple finches in many habitats, but urban landscapes in particular, where their ranges overlap in the east. ("Bird-lore: a bi-monthly magazine devoted to the study and protection of birds and mammals", 1907; Ehrlich, et al., 1988; Wootton, 1987; Wootton, 1996)
Purple finches are monogamous, meaning that one male and one female pair together to breed and raise young each year. Male purple finches perform elaborate courtship displays to attract mates. Once a female is in his territory, a male will rapidly flutter his wings while hopping, thrusting out his breast, raising his crest feathers, cocking up his tail, and singing a soft warble. During this display he often holds nesting material in his bill. The male then flies directly upwards to about 30 cm high. Upon landing, he droops his wings and uses his tail to support him as he raises his head and tilts his body backwards as far as possible. Interested females may respond by drooping and fluttering their wings or beginning to search for a nesting site. (Ehrlich, et al., 1988; Wootton, 1996)
Purple finches breed once each year between the months of April and August. After pair formation, the two birds select a good nesting site, usually in the branches of a conifer. The female builds the nest over 3 to 8 days, with only occasional assistance from the male. She builds a cup-shaped nest out of twigs, roots, grasses, hair, or moss. One to five days after the nest is complete, the female lays 4 to 6 eggs which are greenish-blue in color and speckled with brown or black. The female also incubates the eggs and young with a featherless patch of skin on her belly, called a brood patch. The young hatch after about 13 days and the young can fly in another 13 to 16 days. Fledglings are fed by the parents for an unknown period of time. Juveniles can breed during the following breeding season when they are less than 1 year old. (Ehrlich, et al., 1988; Wootton, 1996)
Young purple finches hatch with no feathers and with their eyes closed. These helpless young birds require lots of care from their parents to survive. Both the male and female select a nesting location, however the female completes most or all of the nest construction. As only the female develops a brood patch, she also performs all of the incubation and brooding. While the female is busy incubating the male frequently provides her with food. Once the young hatch, both parents actively feed the young through regurgitation. The young are fed a diet that is almost entirely seeds. Both parents also remove the waste of their young from the nest to reduce predation or spread of disease. After the young have fledged (left the nest and are able to fly), both parents continue to provide food for an unknown period of time. (Ehrlich, et al., 1988; Wootton, 1996)
The maximum lifespan for purple finches is 14 years. This record is held by a male that was banded at approximately 2 years old, and was then recaptured 12 years later. Banding is often used to reveal lifespans for many species of birds. Nestlings or captured adults are given a small, metal band (like a bracelet) around one leg. This band has a unique identification number for each bird so each bird can be recognized if captured at a later date. Average wild lifespan is estimated at 2 years. Causes of adult mortality are largely unknown, but nestlings are often lost to bad weather, predation, or brood parasitism. Lifespan in captivity is unknown as this species only lives in the wild. (Wootton, 1996)
Purple finches are migratory birds that breed across southern Canada, New England, and west coast regions of the United States, then travel south to overwinter in the eastern United States. This species is one of many that has eruptions, meaning they expand their wintering range during certain years. Eruptions for most species result from population increases that result from abundant food resources, but studies have shown that eruptions in this species result from population increases unrelated to amount of seed available. Purple finches are social during the winter, and often form flocks of 2 to over 200 with others of the same or different species. Common mixed-groups include other finches such as pine siskins or American goldfinches. These groups often roost in conifers and are frequent feeder visitors throughout the winter months.
During the breeding season, however, purple finches become very territorial and mostly are found alone or in breeding pairs. Males sing constantly throughout the breeding season and use displays to deter intruders. Competition with introduced house finches has been detrimental to this species. They lose 90% of territorial interactions with house finches. As a result, purple finches have been excluded in many regions where their range overlaps with that of house finches. (Ehrlich, et al., 1988; Koenig and Knops, 2001; Shedd, 1990; Wootton, 1987; Wootton, 1996)
No specific information exists on territory size for purple finches. During the winter, individuals will tolerate being a minimum 5 cm away from each other. (Wootton, 1996)
Purple finches are known for their bright, musical warbling songs during late winter or early spring, while these birds are traveling in flocks. During the breeding season, males use a different song in defense of their territories. Females also give a short song that is described as finch-like, yet different from a male's song. Females sing while sitting on the nest, but the purpose is currently unknown. Both males and females give a sharp "tick" call when in flight, likely used to keep in contact with others. This species also uses body postures to communicate, mostly in aggressive situations. Three aggressive postures have been identified: low head forward, high head forward, and bill display. Like most birds, purple finches perceive their environments through the senses of sight, smell, taste, touch and hearing. ("Bird-lore: a bi-monthly magazine devoted to the study and protection of birds and mammals", 1907; Wootton, 1996)
Purple finches eat mostly seeds. Diet changes throughout the year to take advantage of foods like insects in the spring and fruits in the summer. They often prefer to eat the seeds of fruits rather than the fleshy portions and eat tree buds and blossoms in early spring. The young are fed almost exclusively seeds. Purple finches often eat the seeds and buds of elms, tuliptree, maples, sweet gum, sycamores, ash, redcedar, juniper, and mountain ash. Purple finches consume the seeds and berries of hackberries, dogwoods, sumacs, hop-hornbeam, beech, grapes, poison ivy, strawberries, and raspberries and blackberries, among others. This species tends to forage on the outer portions of a tree or bush and rarely feeds on the ground. Purple finches have been observed drinking from small pools of water or birdbaths. (Ehrlich, et al., 1988; Wootton, 1996)
Purple finches are mostly exposed to predators during the breeding season, when eggs and young are abundant and helpless prey for predators. Common nest predators include blue jays, scrub jays, Clark’s nutcrackers, common grackles, and red squirrels. To avoid nest predation, the female uses nesting materials from the surrounding environment to create a well-camouflaged nest. If their nest is attacked, a breeding pair will often remain close and make frequent calls or mob the predator. Adult purple finches also fall prey to mammals and other birds including blue jays, barn owls, merlins, sharp-shinned hawks, American kestrels, domestic cats, and domestic dogs. (Wootton, 1996)
As mainly seed eaters, purple finches may be important seed dispersers for plants on which they feed. Adults, young, and eggs serve as prey for a variety of avian and mammalian predators. This species is an occasional host to brown-headed cowbirds, and eastern populations are parasitized more often than western. Brown-headed cowbirds are brood parasites, meaning that the females lay their eggs in the nests of other birds. Cowbird parents do not care for their young, but instead let other species raise their chicks. Often, cowbird chicks will grow faster and out-compete the other nestlings until it is the sole survivor. Purple finches are presumed to be poor hosts, as their young are fed mostly seeds and young cowbirds are adapted to an insect-based diet. Nests of this species often host several types of fly larvae including those of bird blowflies and botflies. Adult finches are parasitized by trematodes, bird lice, ticks, and nasal mites. (Ehrlich, et al., 1988; Spicer, 1977; Wootton, 1996)
There are no known negative effects of purple finches on humans.
Purple finches provide little economic benefit to humans. They are frequent visitors to backyard bird feeders during the winter, much to the delight of bird watchers.
Purple finches are listed as "Least Concern" by the International Union for Conservation of Nature and Natural Resources' (IUCN) Red List. However, the population is currently in decline, which is likely due to habitat loss and competition with introduced house finches. House finches share similar habitats, breeding sites, and food resources. They are more aggressive than the native purple finches and often chase them out of their natural habitats. More research is needed to pinpoint causes of decline and develop specific conservation strategies, especially within the breeding range. ("A Blueprint for the Design and Delivery of Bird Conservation in the Atlantic Northern Forest", 2006; "New Hampshire Wildlife Action Plan. Species Profile: Purple Finch (Carpodacus purpureus)", 2007; BirdLife International, 2009; Ehrlich, et al., 1988; Wootton, 1996)
Rachelle Sterling (author), Special Projects, Tanya Dewey (editor), University of Michigan-Ann Arbor, George Hammond (editor), Animal Diversity Web Staff, Tricia Jones (editor), University of Michigan-Ann Arbor, ADW Zookeeper (editor), University of Michigan-Ann Arbor.
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U.S. Fish and Wildlife Service. A Blueprint for the Design and Delivery of Bird Conservation in the Atlantic Northern Forest. Version 1.0. Hadley, MA: Atlantic Coast Joint Venture. 2006.
University of New Hampshire Cooperative Extension. New Hampshire Wildlife Action Plan. Species Profile: Purple Finch (Carpodacus purpureus). New Hampshire: New Hampshire Fish and Game. 2007.
BirdLife International, 2009. "Carpodacus purpureus" (On-line). IUCN Red List of Threatened Species. Accessed July 19, 2011 at http://www.iucnredlist.org/apps/redlist/details/149563/0.
Ehrlich, P., D. Dobkin, D. Wheye. 1988. The Birder's Handbook: A Field Guide to the Natural History of North American Birds. New York, NY: Simon and Schuster Inc.
Koenig, W., J. Knops. 2001. Seed-crop size and eruptions of North American boreal seed-eating birds. Journal of Animal Ecology, 70: 609-620.
Shedd, D. 1990. Aggressive interactions in wintering House Finches and Purple Finches. The Wilson Bulletin, 102: 174-178.
Sibley, D. 2000. The Sibley Guide to Birds. New York: Alfred A. Knopf, Inc.
Spicer, G. 1977. Two nasal mites of the genus Ptilonyssus (Mesostigmata: Rhinonyssidae) from Texas. Acarologia, 18: 594-601.
Wootton, J. 1987. Interspecific competition between introduced house finch populations and two associated passerine species. Oecologia, 71/3: 325-331.
Wootton, T. 1996. "Purple Finch (Carpodacus purpureus)" (On-line). The Birds of North America Online. Accessed July 13, 2011 at http://bna.birds.cornell.edu/bna/species/208.