Year of the Crossbill

By Julie Hart February 22, 2022
Red Crossbill Loxia curvirostra

2022 may well be the year of the crossbills. Crossbills are not an annual breeders in numbers in New York, but conditions have collided in the Adirondacks to make this a great year for these conifer-loving birds. In fact, it’s the best crossbill year in a generation.  

What makes it a good year for crossbills? 

This year is a good year for crossbills because there are a lot of cones here but not in other parts of the boreal forest. Crossbills use their crossed bill to pry apart the scales on coniferous cones to get at their seeds. They are so specialized on conifers that they’ve adopted a nomadic lifestyle and fly long distances to track large cone crops. They settle down to breed where they find a large food supply.

According to the 2021-2022 Winter Finch Forecast, “extreme weather this summer has played a significant part in this winter’s forecast. With over 2000 forest fires stretching from Northwestern Ontario to British Columbia, record-setting high temperatures across much of western Canada (up to 49.6℃/121℉ in Lytton, British Columbia), and severe droughts in wide areas westward from Lake Superior, food sources have been significantly impacted.”

While Red Crossbill numbers have been on the increase in New York the last decade or more, in October, thousands of White-winged Crossbills were observed moving south at a migration hotspot to our north in Tadoussac, Quebec. Many birdwatchers hoped this was an omen indicating lots of crossbills would spend the winter in the Northeast.

Amazingly, this forecast actually turned out to be true!

This year is likely to be the BEST year for getting out and documenting crossbills for the Atlas. So if you are adventurous and want to spend some time in the northern part of the state this winter, we’ve got tips to help you find these wanderers, what behaviors are easiest to document, and when to go looking.

How to find crossbills

  1. Look for stands of conifers with a lot of cones (i.e., a large cone crop). Crossbills are dependent on conifers for food.
    • White-winged Crossbills in our region prefer 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.
    • Red Crossbills in our region prefer pines, spruces, and hemlock. The most reliable areas of the state are the Adirondacks and central NY, but they are probably under-surveyed in the Taconics and Allegany region.
  2. Listen for White-winged’s distinctive “chut chut chut” flight calls (similar to that of redpolls) or Red’s “kip kip kip” calls to cue you into their presence. Crossbills tend to be pretty noisy when they are around since they are usually in small groups and frequently give this call to communicate with one another.
    • Red and White-winged Crossbills can occur in mixed flocks, but they tend to separate out during breeding since they specialize on different conifer species.
    • It can also be difficult to tell a roaming group from a breeding group because they sing even when they are not actively breeding. In general, breeding groups are small, in an area with a large cone crop, and the males sing a repetitious song from a consistent song perch.
  3. Watch for them on roads. Crossbills, like some other birds and mammals, need to consume sand and salt, which they get from “gritting” along roads.

What 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. Both sexes sing, but males are louder and sing more frequently.

      • White-winged Crossbill. Songs consist of a series of trills interspersed with chirps and warbles (example 1, example 2). 
      • Red Crossbill. Songs, described as pit-pit, tor-r-ree, tor-r-ree, are variable and often contain a mix of call notes, trills, and whistles (example 1, example 2). 

Pairs. A male and a female crossbill flying together doesn’t always indicate a mated pair since they move around in small groups year-round. Breeding pairs (P) can be recognized by a male and female flying together from a nest site to a salt lick or communal drinking site.

Threat displays. Crossbills nest in small groups and forage as a group, so they aren’t territorial in the traditional sense. 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. 

      • There is still much to learn about breeding behavior, with territoriality around the nest one of the unknowns, so use extra caution with the T code and only use it in the rare cases where you see two breeding males fighting over a mate, song perch, or nest. 
      • Another aspect of crossbill behavior we are still learning about is the context for excitement calls. These calls, often called toop calls, are more emphatic and harsher than normal contact notes (White-winged, Red). It seems that crossbills give toop calls in a variety of situations when a perceived threat is nearby, and they appear to be given more commonly during times of nesting. Depending on if toop calls are given in response to another crossbill or a predator, use the T or A code, respectively.

Courtship. Males court (C) females with chasing, courtship feeding, and billing (touching or grabbing the bills of potential mates). Their courtship flight displays (C) are similar:

      • White-winged Crossbill. Birds sing in circular flight with slow wingbeats.
      • Red Crossbill. Birds sing in flight with slow, exaggerated wing beats.

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 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 call that they give until they are independent, about 60 days after hatching. If you hear this, it can be coded as FL for recently fledged.

      • White-winged Crossbill. Sound described as chit. 
      • Red Crossbill. Sound described as chitoo.

When to look for them

NOW!!! Many people have been reporting courtship flight songs of both species the past few weeks (example trip report and another), and even a few reports of carrying nest material have filtered in.

In a couple weeks we should start hearing young crossbills being fed in the nest and by mid- to late-March we should start seeing (and hearing) fledglings. Crossbills and siskins tend to breed synchronously in small groups, so if you figure out the stage of the breeding cycle, you can predict the best time to return and observe the young. Incubation lasts for 2 weeks and the young fledge 2-3 weeks after that. 

In addition to crossbills, Pine Siskins will also start exhibiting pairing and other breeding behaviors by mid-March, and atlasers should be documenting them over the coming months as well! 

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