The Red Crossbill is one of the most unpredictable and mysterious birds in North Carolina. These birds breed in the mountains, but their distribution elsewhere in the state is dependent on food supply. Crossbills are conifer cone specialists. Their plier-like bills are uniquely adapted to pry open cones and crack open the seeds, which make up most of their diet. They are often found peppering the tops of conifer trees in flocks, filling the forest with insistent chatter. Crossbills are a Species of Greatest Conservation Need in the North Carolina Wildlife Action Plan.
Atlas Status:
After the first full breeding season, Red Crossbills were observed within 3 priority blocks. However, they were coded 30 times in non-priority blocks and confirmed via recently fledged young (FL) twice.
Visit the effort map to see where they have been found so far.
North American Red Crossbills can be found as far north as Alaska, and as far south as Nicaragua. Because of their diverse body size, bill shape and habitat requirements, ornithologists now classify crossbills as 9 separate species, each distinguished by vocalization and preferred cone-bearing tree species.
Crossbills forage nomadically, seeking out conifer cones in woodlands across the continent. Their movements and breeding sites are bound by cone availability, which fluctuate greatly in North America. Every couple of winters when the cone crop is low on their normal breeding grounds, these birds spill into more southern territories in search of food. These fluctuations or ‘irruptions’ affect crossbills’ range and abundance in North Carolina. In summer, Crossbills are consistent breeders in the high mountains, breeding in areas where there is ample food. In winter, they visit most of western North Carolina, with moderate influxes of birds to the rest of the state every few years.
Identification
Red Crossbills are medium-sized, stocky finches with distinctive curved mandibles that are crossed at the tip. Adult males are brick-red to reddish yellow with uniformly brown flight feathers and a short, notched tail. Adult females are olive to grayish with a buffy green rump and a gray-white throat. This coloration camouflages them amongst the conifer cones.
Immatures of both sexes are brownish overall with buffy edging on wing coverts and heavy dark brown streaking on their underparts. Birds encountered during this period will almost always be with their parents or in a feeding flock.Juveniles’ bills start uncrossed, resembling other finch species, then overlap as they continue to grow, typically within the first 30 days [more about that here].
Crossbills are highly social year-round and spend most of the day in small feeding flocks. However, finding birds perched and feeding may require some patience, as their movements are erratic and frequent. They are perhaps most often observed flying overhead, identified by their flight call notes ‘jip-jip’.
Habitat and Breeding Biology
Crossbills breed at higher elevations in the mountains of North Carolina, though the bulk of their breeding populations occur in the coniferous forests of southern Canada and the northwestern United States. Crossbills here tend to occupy pine stands in winter, while preferring spruce-fir stands in summer. They are one of very few species in the state that can breed year-round opportunistically. Entirely dependent on the crop of conifer cones, they may breed two or more times in a single year, yet not at all another year. In North Carolina, they typically begin breeding anywhere from late summer to late winter.
They place their bulky nests 10-40 feet above ground in the tops of conifers. The female lays three to five eggs and does all the incubating, which lasts 12-16 days. The male brings food for the female on the nest and helps care for the young once hatched. Once they can fly well, juveniles follow their parents closely. If the female lays a second clutch, the male feeds the first clutch alone.
Crossbills are most easily found in their obligate habitat: conifer stands. However, they can also be observed taking grit from gravel roads, streambanks, and uprooted trees. They consume grit as it contains nutrients such as sodium that are lacking in the rest of their diet.
Where to Look for Red Crossbills:
Crossbills are most easily found in their obligate habitat—high elevation conifer forests—which can be found in these priority blocks:
Finding and Coding
Most years Crossbills do not leave the mountains, so visiting high elevation areas with extensive conifers gives you the best chance of encountering these elusive birds. In winter they have been known to occasionally visit feeders and bird baths. One proven strategy is driving along mountain roads such as the Blue Ridge Parkway and stopping at the frequent overlooks. Listen for their calls and use binoculars to check the tops of nearby conifer trees. These overlooks are also good places to find species such as Canada Warblers, Blackburnian Warblers, Least Flycatchers, and other species that breed in the mountains. If you observe a juvenile crossbill, the FL (recently fledged young) behavior code can only be used if the bird is too young to have flown in from another priority block. Guidance for the use of these codes can be found in the volunteer handbook or at our Understanding Breeding Codes page.
Crossbills are great birds to chase into August or even September when breeding slows elsewhere, since they inhabit cooler high elevations where many species are still exhibiting breeding behavior. Birding the mountains in the summer means escaping the heat and seeing some unique bird species at the southerly tip of their breeding range, not to mention the beautiful landscape!
— Clayton Gibb is a skilled NC Bird Atlas technician working in western North Carolina.
Sources:
Benkman, C. W. and M. A. Young (2020). Red Crossbill (Loxia curvirostra), version 1.0. In Birds of the World (S. M. Billerman, B. K. Keeney, P. G. Rodewald, and T. S. Schulenberg, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.redcro.01
Cornell Lab of Ornithology. 2019. All About Birds. Cornell Lab of Ornithology, Ithaca, New York. https://www.allaboutbirds.org/guide/Red_Crossbill/
LeGrand, H., J. Haire, N. Swick, and T. Howard. 2022. Birds of North Carolina: their Distribution and Abundance [Internet]. Raleigh (NC): North Carolina Biodiversity Project and North Carolina State Parks. Available from http://ncbirds.carolinabirdclub.org.