Red crossbill
The Red Crossbill is a distinctive bird known for its striking red plumage and unique crossed bills, which are specially adapted for extracting seeds from pine cones. These birds belong to the finch family and are typically found in coniferous forests across North America, Europe, and Asia. Adult males display a bright crimson color, while females have yellow-green plumage, both with dark brown wings and tails. Red Crossbills are social creatures that live in small flocks and primarily feed on the seeds of conifers, although they may also consume fruits and insects.
Their breeding season tends to vary according to food availability, with nests built in tree forks where the female lays three to four speckled eggs. The parents work together to feed their young, providing up to 85,000 seeds before the chicks fledge at around three weeks old. However, competition for food can be fierce, leading to challenges for younger birds. In the wild, Red Crossbills can live up to four years, but they may reach eight years in captivity, all while facing threats from various predators.
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Red crossbill
Red crossbills receive their name from their red plumage and their crossed bills. The tips of their upper bills cross over and curve below the upward-curving bottom bills. These bills act like tweezers, removing seeds from the pine cones of the birds' coniferous, or cone-bearing, forest habitats. They are also called common crossbills.
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Passeriformes
Family: Fringillidae
Genus: Loxia
Species: Curvirosta
Red crossbills belong to the subfamily Carduelinae, one of three divisions in the finch family. They are 5 1/2 to 7 3/4 inches (14 to 20 centimeters) long and weigh 1 to 1 1/2 ounces (31 to 42 grams). Their wingspan is nearly twice their body length, measuring 9 3/4 to 11 3/4 inches (25 to 30 centimeters) from tip to tip. Males have crimson plumage, or feathering, with a yellowish tint over most of their bodies. Their tail and wing feathers are brown. Females also have dark brown wings and tail feathers but have yellow-green plumage.
Both males and females have the characteristic crossed bills which give the species its name. The bill’s upper part, called the upper mandible, crosses over the lower mandible and hooks downward. The lower mandible curves upward alongside the upper mandible. They may cross left over right or right over left. These bills are specially designed for prying seeds out of pine cones, the birds' favorite foods. When a crossbill finds a pine cone, the bird twists it off at its stem and grasps it in its stronger claw, while the other claw holds onto the branch. It can then pull out the seeds with its strong bill and crush them with its powerful jaws. They may also eat the seeds of other fruits, such as apples, and other berries. The birds are also able to catch insects.
Red crossbills are social birds living in small flocks in the coniferous woodlands of North America, Europe, and Asia. Coniferous trees bear pine cones, such as pines, spruces, and firs. Because the birds' diet is so particular, they remain in their forest homes unless food is scarce.
The breeding season for red crossbills varies based on when food is available, but the birds usually breed from January to July. After mating, the male and female build a nest in the fork of a tree. The female lays three to four blue-green eggs with brown and light purple spots in the nest made of twigs and grass and lined with hair, feathers, and rabbit fur. She incubates the eggs for 12 to 16 days, keeping them warm so that they will develop and then hatch. After the young hatch, the mother broods them, covering them with her warm body to protect them from the cold and predators. The male and female feed the young up to 85,000 seeds. The young chicks may die in the nest if food is scarce. The chicks fledge, or fly for the first time, at three weeks old, but they stay with their parents for up to two months. Their bills become crossed by this time, and they can feed themselves. Competition for food may be great, and some young birds starve because they are not strong enough to compete for the seeds.
Birds of prey and small mammals prey on red crossbills, including steller's jays (Cyanocitta stelleri), red and Douglas squirrels (Tamiasciurus), sharp-shinned hawks (Accipiter striatus), and northern pygmy owls (Glaucidium gnoma). When food is available and if predators do not attack them, red crossbills may live for 4 years. In captivity, they may live up to 8 years.
Bibliography
"Common Crossbill." The Woodland Trust, www.woodlandtrust.org.uk/trees-woods-and-wildlife/animals/birds/common-crossbill. Accessed 15 Apr. 2024.
Dewey, Tanya. "Loxia Curvirostra." Animal Diversity Web, animaldiversity.org/accounts/Loxia‗curvirostra. Accessed 15 Apr. 2024.