Red Crossbills (Loxia curvirostra) are medium sized passerines (family Fringillidae) that occur year-round in North America’s coniferous forests. They subsist exclusively on conifer seeds from spruce (Picea), larch (Larix) and pine (Pinus) trees, and use the tips of their crossed mandibles (i.e., bills or beaks) to pry out kernels from partially closed or closed cones. Their strong association with conifer trees has earned them the name “spruce mope” in Newfoundland. Red Crossbills’ dependence on seeds explains much about their behaviour and ecology. For example, native coniferous trees bear their cones erratically over time and space. A heavy cone crop one year may be followed by several years of no new cone production. As a result, crossbills may desert coneless areas en masse. Such abrupt, large scale movements of birds into new foraging and breeding territories are called irruptions. Red Crossbills often flock year-round, a behaviour that improves foraging efficiency and predator avoidance. The Sharp-shinned Hawk is a potential predator of adults and young birds, and red squirrels may depredate nests.
Red Crossbills and White-winged Crossbills are the only birds in North American with crossed bills. The latter species is distinguished from the Red Crossbill by the presence of bold white wing bars; male White-winged Crossbills are also rose-pink in plumage. Adult male Red Crossbills vary in colour, from poppy red, or reddish yellow, to even greenish yellow (off-coloured male are extremely difficult to identify). The wings and tail are dark brown or black. Females are olive-gray, with rump and underparts yellow. Juveniles are brownish overall, and are heavily streaked above and below. They may resemble a female Purple Finch, or a large Pine Siskin. Listen for the voice of Red Crossbills. They give, short, but distinct ‘kip-kip’ during solitary and group flight. These resonant calls probably act as advertisements, helping birds to locate mates, flocks, or appropriate habitat.Please Report Red Crossbill Sightings!Red Crossbills are subject to intense interest by bird lovers and scientists alike. Their varying behaviours and forms raise many questions regarding evolution and speciation. Ten unique ‘call types’ have been identified, and Newfoundland appears to have its own unique Red Crossbill population. However, Red Crossbills - once relatively abundant in Newfoundland - have now become scarce, leading governments to list the Newfoundland Red Crossbill as an endangered species. If you see a Red Crossbill, make note of the date and location, and post it on nlnature.com!
Fringillidae – the biological class of birds that includes the perching birds commonly referred to as ‘finches’. These include, among others, Newfoundland birds such as the Red and White-winged Crossbill, Purple Finch, Pine Grosbeak, and American Goldfinch.