The Red Crossbill (Loxia curvirostra) is a small finch found across North America and Eurasia. They are named for their unique crossed mandibles, which they use to extract seeds from conifer cones. There are 10 recognized “types” of Red Crossbill in North America, distinguished by differences in bill size and shape as well as vocalizations. Here we will focus on Type 7, one of the more recently recognized types.
What are the different types of Red Crossbill?
Ornithologists recognize 10 different “types” of Red Crossbill in North America based on differences in body size, bill size and shape, flight call vocalizations, and habitat preferences:
| Type | Bill Size | Range |
|---|---|---|
| Type 1 | Small | Widespread in western North America |
| Type 2 | Medium | Widespread in eastern North America |
| Type 3 | Large | Southwestern Canada, Pacific Northwest, Appalachian Mountains |
| Type 4 | Medium-large | Pacific Northwest |
| Type 5 | Medium-small | Widespread in coniferous forests |
| Type 6 | Small | Localized in Cyprus populations |
| Type 7 | Small | Alaska, western Canada |
| Type 8 | Small | Localized in Newfoundland |
| Type 9 | Medium | Localized in Newfoundland |
| Type 10 | Small | Localized in Alaska |
These types likely represent distinct populations that have evolved specialized bill shapes to feed on different conifer cones. Their ranges may overlap but they seem to remain reproductively isolated.
When was the Type 7 Red Crossbill recognized?
The Type 7 Red Crossbill was first recognized as a distinct type in the late 1990s based on differences in vocalizations compared to other types. It took some time for ornithologists to collect enough recordings and data to confirm Type 7 as a distinct form. The first technical published description characterizing Type 7 was in a 2013 paper by ornithologist Dr. Craig Benkman and colleagues.
Where is the Type 7 Red Crossbill found?
The breeding range of the Type 7 Red Crossbill is centered in Alaska and northwestern Canada. They breed primarily in black spruce forests in these northern regions.
During winter, Type 7 crossbills may wander further south into Canada and the northern United States in search of food. They have been recorded as far south as Oregon and Wyoming during winter months.
What does the Type 7 Red Crossbill look like?
The Type 7 Red Crossbill is a small, finch-like songbird with a wingspan of about 8-10 inches. As with all Red Crossbills, they are named for their crossed mandibles.
Plumage is dull red overall, with dark wing and tail feathers. Males tend to be redder, while females are more yellowish. Like the other types, males and females look very similar.
Their petite size and small bill distinguish Type 7 from most other Red Crossbill types. Only Type 10 is smaller-billed. Type 7 has a more tapered, pointed bill compared to other small-billed types like Type 1.
What sound does the Type 7 Red Crossbill make?
The vocalizations of the Type 7 Red Crossbill are higher-pitched and faster-paced compared to most other types. Their flight calls are a quick series of rising “jip” notes.
During courtship at the nest, males sing a rambling warble, often ending with a buzzy trill. The songs are chattery and complex compared to other types.
Researchers monitor distinct flight calls and songs to identify Type 7 crossbills in the field. Vocal analysis allows ornithologists to distinguish the different types.
Behavior and Ecology
The Type 7 Red Crossbill has many interesting behaviors and adaptations to its northern, coniferous forest habitat. Here we cover topics like their feeding, breeding, and social behavior.
How does the Type 7 Red Crossbill feed?
Like all crossbills, the Type 7 is specially adapted for extracting seeds from conifer cones. Their crossed mandibles allow them to pry open cones and remove the seeds with their tongue.
Type 7 crossbills primarily feed on black spruce seeds within cones. Their small size and pointed bill are ideal for opening the soft scales of black spruce cones to access the small seeds inside.
They use their feet to hold cones steady against a branch while they pry them open. You may see pieces of cone falling to the ground as they work. Groups will often feed in the same tree, calling back and forth.
When does breeding occur?
Timing of breeding in Type 7 Red Crossbills depends on an abundance of mature black spruce cones. This is linked to weather patterns and seasonal changes in the forests.
Breeding can occur at any time of year when food is plentiful. Nesting records peak between May and July but have been documented in all months. They breed opportunistically based on resources.
How do Type 7 Red Crossbills build their nests?
The nest of a Type 7 Red Crossbill is an open cup built 3-13 feet off the ground, typically in a horizontal branch or fork of a conifer tree.
Both male and female crossbills build the nest. They construct it from twigs, conifer needles, bark strips, lichens, and other plant material. Moss, feathers, or animal hair may line the inner cup.
Nests are typically placed near an abundance of conifer cones for feeding while incubating eggs and raising nestlings.
How many eggs do they lay?
A typical Type 7 Red Crossbill clutch contains 3-4 eggs. The eggs are pale bluish-white with reddish-brown spotting.
Only the female crossbill develops a brood patch and incubates the eggs. The male will continue to feed the female while she incubates. Incubation lasts 12-16 days before hatching.
How do the parents care for nestlings?
Both parents feed the nestlings with regurgitated seeds and insects. The chicks fledge from the nest around 2-3 weeks after hatching.
Young crossbills remain with their parents for 1-2 months after leaving the nest. The family will stay together and travel in a small flock while the juveniles learn to feed independently.
What’s their social structure like?
Red Crossbills live in small nomadic flocks outside of breeding season. A flock may contain a mated pair along with their recent fledglings, plus other unrelated juveniles and adults.
They roam widely in search of areas with abundant cones. Flocks communicate with constant contact calls while feeding and flying. If food is scarce, larger flocks may congregate in productive areas.
How do they deal with predators?
Crossbills are vulnerable to predators like sharp-shinned hawks, squirrels, and jays when feeding. They are also at risk from predators like weasels and owls when nesting.
Flocks keep watch for predators and signal warnings with alarm calls. Their nomadic movements may also reduce predation by not staying too long in one area. Nesting in dense conifers offers some protection as well.
What is their conservation status?
Overall, Red Crossbills are common and widespread across their habitat range. However, the Type 7 subspecies has a more restricted distribution focused in northern Alaska and Canada.
Their specialized habitat preferences also make them vulnerable to climate change affecting boreal forests. Continued monitoring is needed to watch for potential declines. Currently the Type 7 Red Crossbill is considered a species of Least Concern by the IUCN Red List.
Interaction with Humans
The Type 7 Red Crossbill primarily resides in remote boreal forest regions with little direct interaction with humans. But here are some ways these birds overlap with people.
How were they named?
The Red Crossbill’s English name refers to the crossed appearance of their mandibles. Their scientific genus Loxia comes from the Greek word loxos meaning “crosswise.”
The different types were originally classified by their bill size – Types 1 to 3 for small, medium, and large. Additional types were later named in order of their discovery, up to Type 10 which was found most recently.
Where can I see a Type 7 Red Crossbill?
Your best chance to find a Type 7 Red Crossbill is by searching within their core range in Alaska and Canada. Look for flocks feeding in black spruce forests, listening for their chattering flight calls.
They are irregular winter visitors south into the northern U.S. states and at higher elevations further south in the Appalachian Mountains. Use eBird range maps to find recent sightings.
How can we support Red Crossbill conservation?
Some ways to help support Red Crossbill populations include:
– Protecting intact boreal forest habitats from excessive logging and development.
– Allowing wildfires to play their natural role in regenerating forest stands.
– Providing nest boxes where natural nest sites may be scarce.
– Reporting crossbill sightings to eBird to help track populations.
– Supporting forestry practices that maintain a mix of young and mature conifer stands.
– Minimizing use of pesticides that may accumulate in food sources.
– Educating others about crossbill ecology and conservation needs.
Conclusion
In summary, the Type 7 Red Crossbill is a unique finch specially adapted to feed on black spruce cones within the boreal forests of Alaska and Canada. Their crossed bills, small size, and vocalizations distinguish them from other Red Crossbill types sharing parts of their range.
While Type 7 crossbills remain common, continued monitoring is important for this specialist species dependent on a fragile northern ecosystem. Protecting habitats and conifer resources will contribute to the future conservation of these amazing birds.
I hope this detailed overview helps explain what defines the Type 7 Red Crossbill and highlights some interesting aspects of its ecology and behavior. Let me know if you need any clarification or have additional questions!
