The Red Crossbill Loxia curvirostra) is listed as an irregularly uncommon resident of New Brunswick. It is a member of the Fringillidae family. Small flocks wander around the province at any time seeking their favourite food, seeds from the cones of coniferous trees. They move sporadically from one food source to another. They are quite tame, often feeding contentedly ignoring any human interference around them. They can be seen along the shoulders of roads in winter where they gather to feed on road salt.
This species is considered nomadic and irruptive. Its movements and occurrence are tied closely to the availability of conifer seeds. Although they breed normally in late summer (June to September) when seed production is high, they are known to nest at any time of year if they find a suitable cone crop. Given that coniferous trees do not produce cones every year and some years produce a heavier crop than others, erratic movements of the species are expected.
The range of this species is extensive. It is a permanent resident of most of southern Canada from Newfoundland across southern Canada to the west where its range covers all of Alberta and British Columbia and into Yukon. The range extends southward to include most of the western US and into Mexico. Most of that area provides permanent residency but the species appears as a winter resident only in much of the mid-western US. This species is paleoarctic, occurring also in northern and central Europe, and into north Africa. In Europe it shares its habitat with three other crossbill species, the Two-barred Crossbill (White-winged Crossbill), the Scottish Crossbill and the Parrot Crossbill.
The Red Crossbill is a sexually dimorphic species. Males look quite different from females. It is a chunky medium-sized finch, 16 cm long and slightly larger than a close cousin also occurring here, the White-winged Crossbill. It has a large head and a notched tail. Its main feature is its stout crossed bill, the curved top beak crossed over the curved bottom beak. The male is entirely brick red with dark wings and tail. The wings have no wing bars, a distinguishing feature. The back has some dark scaling and the under tail coverts are white with black chevrons. See top photo. The female is light to dark yellow overall with dark wings and tail. The throat is light gray. The juvenile is brown streaked overall but paler underneath. It may have pale narrow wing bars. The female pictured above shows a very pale yellow colouring.
The binomial name for the Red Crossbill, Loxia curvirostra, is derived from the ancient Greek work loxos meaning 'crosswise' and the 'curvirostra' is Latin for 'curved bill'. The species was given this name by Carl Linnaeus in 1758. This species was well known long before that. It has been mentioned in the literature since 1254 from which a sketch by Matthew Paris survives of a crossbill holding fruit in its beak. The species was mentioned many times since then in early literature, drawings and sculptures. A quotation from Roger Twysden from 1593 describing a flock of crossbills in an orchard states, "in the apple season of 1593, an immense multitude of unknown birds came into England ... swallowing nothing but the pippins, and for the purpose of dividing the apple, their beaks were admirably adapted by nature, for they turn back, and strike one point upon the other, so as to show .. the transverse sickles, one turned past the other."
Red Crossbills show a great variation in bill shape, voice and size and their species may be comprised of many species. Some are now designated as subspecies. Because some are genetically distinct some will likely eventually be put into separate species. Sorting them out is a difficult task. Nine (or ten) types are now listed for North and Central America. European species add even more complexity to the puzzle. The different forms are called 'calls' or 'types'.
Red Crossbills normally nest in mid-to-late summer. The nest is built near the end of a large conifer branch and is a shallow saucer made of bark strips, grass and roots and lined with moss and plant down. The female lays 3 to 4 light green or blue eggs spotted with brown or lavender and she incubates them 12 to 18 days. This species eats a variety of foods; insects, seeds, buds, fruits and, of course, the seeds of coniferous trees. Large-billed individuals prefer pine cones and smaller-billed individuals like spruce cones. A tree that has been heavily fed upon by crossbills shows cones that have only their central stem remaining and many, many cone scales on the ground under the tree. When birders are looking for crossbills, they check to see how the cone crop is in the area and then start watching the tops of conifers for a group feeding there. They also listen for the double-noted call, a kip kip sound. The Red Crossbill song is several double-noted sounds followed by a warbling trill. It is a harsher sound than that of the White-winged Crossbill.
Red Crossbills are interesting birds. I am always delighted when I see them. I am in no hurry to have the researchers sort out the variation in this species. I can't imagine how difficult it would be to sort out up to 10 different species of Red Crossbills. That would make birding very difficult!
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