Like their name, crossbills have a crossed bill, almost like a pair of twisted scissors. “Crossbills are finches whose beaks, as their name suggests, cross at the tip. This seeming malformation is actually a wonderful adaptation that allows the birds to access seeds hidden between the scales of conifer cones, seeds that are inaccessible to other species of birds,” said Craig Benkman at the annual American Ornithologists’ Union meeting. “The curved bills, coupled with crossbills’ ability to shift their lower mandibles sideways, allow the birds to pry open conifer cones and extract the seeds with their tongues.”
There are ten different types of crossbills and each bill accommodates a different type of conifer cone, as preferred by each species. “The sizes of the crossbills’ beaks,” Craig added, “closely match the cones they feed on and can efficiently pry apart the cone scales to get at the seed inside.” The top of the bill is straight and the bottom curves to the left or right. The “crossed bill” shape provides these birds with a competitive advantage.
Ron Pittaway released his annual finch forecast for 2017 – 2018. The Finch Forecast is anticipated by many people in the birding community. With Ron’s extensive knowledge and resources, birders can discover what types of uncommon birds they may see in their backyards this winter. Ron mentioned the movement of two crossbills, in particular. “There will be a good showing of Red Crossbills in Ontario and the Northeast this winter. Red Crossbills probably will be breeding this winter into next spring. Expect to hear them singing and to see streaked juveniles.” See photo on the right to see the female Red Crossbill, with yellow and greenish coloring, feeding on the seeds inside the pinecone.
Ron also noted White-winged Crossbills have already arrived and “flooded into the Northeast over the summer, drawn here by the bumper cone crops. They will probably be breeding this fall and winter. Watch and listen for their loud trilling songs from tree tops and during circular slow-flapping display flights. Expect to see streaked juveniles in the flocks.”
The Cornell Lab further observed the scissor-like bill, “This physical adaptation grants the White-winged Crossbill access to seeds from pine cones that other species with ordinary bills simply can’t get to. The crossed bill acts as a barrier to species competing for food within the same habitat.”
Look for crossbills this winter throughout the northeast. If the bird’s bill looks a little twisted or “wrong,” then you may be looking at a crossbill! Enjoy watching the video below to see the crossbill feeding on a conifer cone. About 50 seconds into the video, the crossbill extracts the seed from the cone, using their scissor-like bill.
View the most recent Winter Finch Forecast by expert Ron Pittaway. Happy Birding!
Written by Dawn Coutu
SOURCES AND INTERESTING LINKS:
“Coming for Winter 2017–18: A Crush of Crossbills,” Devokaitis, Marc. All About Birds, The Cornell Lab of Ornithology. 14 Dec. 2017. 27 Dec. 2017. <https://www.allaboutbirds.org/a-crush-of-crossbills/>.
“Crossbills of North America: Species and Red Crossbill Call Types,” eBird, The Cornell Lab of Ornithology.
“From here to where? Understanding crossbill movements,” Witynski, Max. Project FeederWatch, The Cornell Lab. 26 Jan. 2016. 27 Dec. 2017. <https://feederwatch.org/blog/from-here-to-where-understanding-crossbill-movements/>.
“Inside The Massive Winter Irruptions Known As Superflights,” Powell, Hugh. All About Birds, The Cornell Lab of Ornithology. 15 Jan. 2013. 27 Dec. 2017. <https://www.allaboutbirds.org/inside-the-massive-winter-irruptions-known-as-superflights/>.
“North American Red Crossbill Types: Status and Flight Call Identification,” eBird, The Cornell Lab of Ornithology.
“Red Crossbill,” All About Birds, The Cornell Lab of Ornithology. 2015. 28 Dec. 2017. <https://www.allaboutbirds.org/guide/Red_Crossbill/id>.
“Science At Work: How Many Kinds Of Red Crossbills Are There, Anyway?” Hochachka, Wesley. All About Birds, The Cornell Lab of Ornithology. 2 Aug. 2011. 27 Dec. 2017. <https://www.allaboutbirds.org/science-at-work-how-many-kinds-of-red-crossbills-are-there-anyway/>.
“White-winged Crossbill,” All About Birds, The Cornell Lab of Ornithology. 2015. 28 Dec. 2017. <https://www.allaboutbirds.org/guide/White-winged_Crossbill/id>.
“White-winged Crossbill Foraging Adaptation,” Bird Academy, The Cornell Lab of Ornithology. 2017. 28 Dec. 2017. <https://academy.allaboutbirds.org/white-winged-crossbill-foraging-adaptation/>.
“White-Winged Crossbills: Ecology And Conservation During An Irruption Year,” McCarthy, Clara. All About Birds, The Cornell Lab of Ornithology. 15 Apr. 2009. 27 Dec. 2017. <https://www.allaboutbirds.org/white-winged-crossbills-ecology-and-conservation-during-an-irruption-year/>.
“Winter Finch Forecast 2017 – 2018,” Pittaway, Ron. 21 Sep. 2017. <http://www.jeaniron.ca/2017/wff17.htm>.