Species Spotlight - White-winged Crossbill

By Julie Hart October 20, 2021
White-winged Crossbill Loxia leucoptera

Like their counterpart the Red Crossbill, White-winged Crossbills are nomadic, following the available cone crop and settling down to breed where they find a large food supply. Their bill is slightly smaller than a Red Crossbill, but they use it the same way. They shove the tip of their bill in between the cone scales, brace themselves with their feet, then use the strong leverage of their crossed bills to pry open the scale and pull the seed out with its tongue. Their smaller bill means they are specialized at extracting seeds from the smaller, softer cones of spruce, tamarack (or larch), and fir.

This adaptation has allowed them to take advantage of this untapped resource, but it also makes them highly dependent on conifer trees, so much so that they have adopted a nomadic lifestyle flying long distances to track large cone crops. This adds to their appeal for us birders, because we don’t know when or where we may run into them. But we can increase our chances by following large-scale movements of crossbills (called irruptions) and learning a bit about their biology.

How to Find Them

Crossbills are dependent on conifers for food. In irruption years, look for stands of conifers with a lot of cones (i.e., a large cone crop). The preferred conifers of White-winged Crossbills in our region are spruce, tamarack, and fir. The most reliable areas of the state are the Adirondacks and central NY, but they have also bred in the Tug Hill, Champlain Valley, Rensselaer Hills, Catskills, and Allegany county.

Listen for their distinctive “chut chut chut” flight calls (similar to that of redpolls) to cue you in to their presence. Crossbills tend to be pretty noisy when they are around since they are usually in small groups and frequently give this call. White-winged Crossbills also give a rising whee call that is similar to some redpoll, siskin, or goldfinch flight calls. This rising call is never given by Red Crossbills. They can occur in mixed flocks with Red Crossbills, but tend to separate out during breeding since they specialize on different conifer species.

Crossbills, like a number of other boreal specialists, are fairly tame. They spend most of their time up in the canopy eating seeds, so they often don’t change their movements when people are nearby. They are more skittish when they are gritting, that is, eating small stones and salt from roadways.

Read more tips on how to search for crossbills on the Finch Network.

Identification

There are two species of crossbills in NY, Red Crossbill and White-winged Crossbill. You can tell Red and White-winged Crossbills apart by the wing patch. White-winged Crossbills have a bright white wing patch while Red Crossbills don’t.

Males are pink to red, females are yellow-green, with both adults showing faint streaking on the breast. Juveniles are streaked brown and less pronounced wing bars. Young males may appear orange as they mature. All ages have a noticeably smaller bill and longer tail than Red Crossbills.

 

Breeding Calendar

White-winged Crossbills are nomadic and track cone crops across the boreal forest of Canada and sometimes irrupting further south in the Appalachians, Rockies, and Sierras. They often travel large distances between breeding attempts. However, they always time their breeding to match the cone cycle. In the Northeast, they exhibit two distinct breeding periods, once in the winter (Jan-April) and again in the summer (Jul-Sep).In previous Atlases, they have been confirmed breeding in NY in all months except November and December.

Since we don’t have many breeding records for crossbills in the Atlas (yet!), we can’t provide a detailed phenology chart. Instead, here is some information on the different nesting stages to help you gauge the timing of different behaviors (next section), whether you find them in winter or summer.

Incubation. The female incubates her three eggs for 14 days. Females are fed by the males during winter nesting so that the eggs are not left exposed to the cold temperatures.

Nestlings. The female stays on the nest almost constantly for 5 days after the young hatch. After that she takes longer forays away from the nest to forage; the young nestlings may enter a state of torpor during colder weather while she is away. Both parents feed the young. Fecal sacs are consumed for the first few days, after that they are deposited on the rim of the nest.  

Fledgling. Young likely fledge around 20 days at which time they follow the parents around closely. Parents feed young for a month or more after fledging, until the bill of the young is fully crossed and they are able to forage efficiently on their own.

 

Behaviors to Look For

Crossbills spend a lot of time high up in the tops of trees, so they can be hard to confirm breeding. Here are the most common behaviors you will encounter and how to code them.

Singing. Birds sing (S, S7, M7) in flight or perched from the top of a tree. Songs consist of a series of trills interspersed with chirps and warbles (example 1, example 2). Both sexes sing, but males are louder and sing more frequently. When song is given in flight, they often fly in circles with slow wingbeats.

Threat displays. Crossbills make an array of excitement and alarm calls. Often called toop calls, they are more emphatic and harsher than normal contact notes (excitement calls). They are given in response to some stressor. They should not be coded unless used when a predator is nearby, in which case, use A (agitated). Crossbills nest in small groups and forage as a group, so they aren’t territorial in the traditional sense (defending a territory from other crossbills) and should not be coded with T. However, they do compete over food and perches, so you may see them getting aggressive towards other birds, sometimes even ending in chases and physical fights.

Courtship. Males court (C) females with chasing, courtship feeding, and billing (touching or grabbing the bills of potential mates). Their courtship flight display (C) consists of birds singing in circular flight with slow wingbeats.

Nest building. Both sexes supply twigs, grasses, lichens, and other materials for the nest (CN), but the female does most of the building (NB). Their cup nests are well concealed in conifer trees (usually spruce) 1-20 m off the ground.

Feeding young. Parents feed young (FY) by regurgitating whole seed kernels and fluids from their crop. You are unlikely to observe feeding of young at the nest, but you may see this behavior with fledglings.

Fledgling calls. Juveniles have a distinctive chit call up until they are independent, about 60 days after hatching, and can be coded as FL for recently fledged.

 

Annual Finch Forecast

Each year a finch forecast is compiled that predicts the movements of finches across North America based on cone crops in the boreal forest. The 2022 Finch Forecast is posted on the Finch Research Network website, and it says we should be looking for more breeding crossbills in the Adirondacks this winter!

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