Tips for finding these unique finches
By Joan Collins
There are six “crossbill” species—finches with mandibles (lower part of their bill) that cross either to the left or right. Two, white-winged crossbill and red crossbill, breed in the Adirondacks.
With an excellent red spruce cone crop in the Adirondacks, red crossbills nested during late summer of 2024. Watch for late winter nesting in 2025.
Crossbills are social and nomadic, wandering, sometimes across continents, searching for conifer seeds that unpredictably produce cones. It is a mystery how they know where to find these good feeding areas. They nest any time if they can find sufficient cone seed crops to feed their young.
The Adirondack Explorer thanks its advertising partners. Become one of them.
Red crossbills are absent from the Adirondacks when all conifer species simultaneously cycle with poor cone crops. Their habitat is in lowland to submontane mature coniferous forest in the northern hemisphere.
Identifying the red crossbill
In North America, the 11 known “types” of red crossbills are differentiated by their calls. Although they breed mostly within their own call type, there are complicating factors in splitting them into separate species since they often overlap in breeding ranges. In the Adirondacks we have a red crossbill with a call type recently named type 12, but types one, two and 10 can occur, and in some years types three and four can show up.
Red crossbill, a medium-sized finch, has black eyes, legs, toes and claws. Males are deep brick red to reddish yellow. They have dark brown flight feathers and a short, deeply notched dark brown tail. Females are olive to grayish with greenish or greenish-yellow breast and rump. Juveniles are heavily streaked dark brown.
The mandibles cross at the tip of the bill with 50% crossing to the right and 50% to the left. (For white-winged crossbill, 75% of mandibles cross to the right and 25% to the left.) It takes a month for fledglings’ bills to cross. The biological mechanism is yet another mystery.
The Adirondack Explorer thanks its advertising partners. Become one of them.
In the Adirondacks, red crossbills feed on seeds of red, white and black spruces, balsam fir, eastern hemlock, tamarack, and red and white pines. Availability of water is important as they drink 22% of their body mass per day, even in winter.
Their uniquely adapted bill is used to separate the cone scales so their tongue can grab the seed. The bill is held slightly open and the mandible point is placed under a scale, then the crossbill bites down, thereby separating the scales.
They use the foot opposite the side to which the mandible crosses to hold the cone. The woody seed coat is removed before the kernel is eaten. Red crossbills rapidly consume huge numbers of kernels as they acrobatically forage. They use grit to help digest their diet.
Red crossbill songs are varied, but sound like, “pit, pit, tor-r-ree, tor-r-ree” and calls are heavy “whit whit whit” or “jit jit jit.” Males sing from the tops of conifers, making them easy to spot.
The Adirondack Explorer thanks its advertising partners. Become one of them.
Where in the Adirondack Park you can find them
Nesting typically occurs in the Adirondacks twice a year when cone crops are plentiful, in mid/late summer and again in late winter/early spring.
Red crossbills can mate by several months old. Mates are selected from within their flock and pairs are monogamous. Males feed their mates during courtship—an interesting behavior to observe with their crossed bills.
In the Adirondacks, they mainly nest in white pines. Breeding is usually colonial with many pairs nesting near one another. Females build the nests and incubate the eggs. The female is fed by the male while she is on the nest.
Nestlings are fed regurgitated seed kernels. Adults continue to feed fledged young until they can extract and shell seeds on their own at about 45 days old.
The U.S. and Canada population of red crossbills declined 12% between 1970-2014 according to Breeding Bird Survey data.
The Adirondack Explorer thanks its advertising partners. Become one of them.
Threats include predation by sharp-shinned hawks, Canada jays, northern shrikes and American kestrels. They die from car strikes when gritting and when red squirrels compete for cones.
Red crossbills need mature coniferous forests. Conifers need to reach 30 years to produce cones, or longer for maximum cone production. Shortened logging rotations limit cone production.
Climate change is resulting in vast numbers of trees dying as a result of insects and increasing wildfires. The warmer temperatures in winter and spring are causing earlier and more complete shedding of seeds from cones increasing the window of scarcity between shed seeds and new seed crops.
Top photo: Red Crossbill (Loxia curvirostra) likely type 10 – adult male feeding in Pitch Pine (Pinus rigida). Photo by Larry Master
Don’t miss out
This article first appeared in a recent issue of Adirondack Explorer magazine.
Subscribe today to get 7 issues a year delivered to your mailbox and/or inbox!
Leave a Reply