The black-backed woodpecker (Picoides arcticus) is a fascinating bird found in forests across North America. As their name suggests, these woodpeckers have black plumage on their backs and wings, with white plumage on their undersides. They use their strong, chisel-like beaks to drill into trees and feed on the insects inside the trunks and branches. But what exactly do these specialized birds eat? Let’s take a closer look at the diet and feeding habits of the black-backed woodpecker.
Main Food Sources
The black-backed woodpecker feeds primarily on wood-boring beetle larvae that are found under the bark of dead and dying trees. This includes species such as:
- Long-horned beetles
- Metallic wood-boring beetles
- Flatheaded wood borers
- Emerald ash borers
These wood-boring insect larvae provide an abundant, nutritious food source for black-backed woodpeckers. The birds use their chisel-like beaks to hammer away at the outer bark of trees to access the larvae inside. Their specially adapted tongues can then easily extract the larvae from their burrows.
In addition to wood-boring beetle larvae, black-backed woodpeckers will also feed on:
- Adult beetles
- Ants
- Caterpillars
- Spiders
- Other insect larvae
They glean these other insects from under the bark and among the cracks and crevices of dead and dying trees. These supplementary insects provide extra nutrition and variety to the woodpecker’s diet.
Preferred Tree Species
Black-backed woodpeckers do not feed on just any dead or dying tree. They prefer trees recently killed by things like forest fires, floods, insect outbreaks, and disease. Some of their favorite tree species to feed on include:
- Lodgepole pine
- Ponderosa pine
- Western larch
- Engelmann spruce
- Aspen
- Birch
These tree species tend to host larger numbers of wood-boring beetle larvae after disruptive events that stress or kill them. The black-backed woodpecker is specialized at exploiting these newly available food resources.
Feeding Behavior
Black-backed woodpeckers exhibit some fascinating feeding behaviors and adaptations:
- They are one of only a few woodpecker species known to engage in “bark stripping” – Using their sharp beaks to peel away outer bark layers to access insects underneath.
- They use their long, barbed tongues to extract beetle larvae deep within their burrows.
- They can consume 85% of their body weight in beetle larvae per day.
- They flick their tongues up to 13 times per second when feeding.
- They store extra food in special cavities they excavate in trees.
This specialized feeding behavior allows them to take advantage of seasonal pulses in wood-boring beetle numbers. It also gives them an important ecological role in recycling nutrients back into the forest ecosystem.
Adaptations for Feeding
Over the course of their evolution, black-backed woodpeckers have developed specialized physical features and adaptations to help them access and feed on wood-boring beetle larvae:
- Extra-long, barbed tongue to extract larvae from deep burrows.
- Specialized hyoid bones in tongue give it extra protrusibility.
- Reinforced skull to withstand repeated hammering on wood.
- Higher density of sensory pits in bill help locate prey.
- Feet have two toes facing forward and two facing back for excellent grip and balance.
- Stiff tail feathers provide support against tree trunks while feeding.
Their unique feeding ecology has shaped the evolution of the black-backed woodpecker into the highly specialized insect-eating bird it is today.
Role in the Ecosystem
As insect-eating birds specialized in consuming wood-boring beetle larvae, black-backed woodpeckers play an important role in the forest ecosystems they inhabit:
- They help control forest insect pest populations like bark beetles.
- They accelerate the decomposition of dead and dying trees.
- Their excavated cavities provide nesting sites for other bird and mammal species.
- They recycle nutrients from dead trees back into the ecosystem.
By feeding extensively on beetle larvae in stressed, declining, or burned forests, black-backed woodpeckers help keep insect pest populations in check and speed up the transition to new forest growth. Other species benefit from the nesting and shelter sites they excavate.
Diet Changes by Season
While wood-boring beetle larvae make up their main food source year round, the diet of black-backed woodpeckers does change a bit depending on season:
- Spring – More beetles and ants are eaten as a protein boost for breeding season.
- Summer – They focus extensively on feeding nestlings with beetle larvae and caterpillars.
- Fall – Bark beetle larvae remain the main food before migration or overwintering.
- Winter – They eat beetle larvae from under the bark of recently dead trees.
The seasonal shifts in prey availability drive some minor seasonal changes in the black-backed woodpecker’s diet. But they specialize on wood-boring beetle larvae for the majority of the year.
Differences Between Males and Females
There are no major differences between male and female black-backed woodpeckers when it comes to their main diet and feeding habits. Both sexes primarily consume wood-boring beetle larvae obtained by drilling into the bark of dead and dying trees.
However, there are some subtle differences in how the sexes feed:
- Males tend to focus on excavating nesting and roosting cavities in softer wood.
- Females do more extensive foraging for food on tree trunks and branches.
- Males regurgitate food for incubating females and feed nestlings.
So while their diets are fundamentally the same, males and females divide up duties when it comes to obtaining food and caring for young. This allows them to most efficiently exploit their specialized wood-boring beetle food source.
Common Questions
Here are answers to some other common questions about the diet and feeding behavior of black-backed woodpeckers:
Do black-backed woodpeckers eat seeds or nuts?
No, black-backed woodpeckers consume almost exclusively insects, especially beetle larvae extracted from under tree bark. They do not eat vegetable matter such as seeds or nuts.
How do they get beetle larvae out of trees?
Black-backed woodpeckers use their chisel-like beaks to hammer away and peel back the outer tree bark. Their specialized tongues can then easily hook and extract beetle larvae deep from their burrows.
How much do they eat per day?
Black-backed woodpeckers can consume up to 85% of their body weight in beetle larvae per day – an impressive amount for a bird! All that hammering and feeding keeps them busy.
Do black-backed woodpeckers store food?
Yes, they will excavate special chambers and cavities in trees where they wedge in uneaten beetle larvae and other insects to feed on later. This allows them to take advantage of temporary abundances.
What time of day do they feed?
Black-backed woodpeckers are most active in the early morning and again in the late afternoon and evening. Those are peak times for them to feed extensively on beetle larvae under the bark.
Conclusion
In conclusion, the unique woodpecker species known as the black-backed woodpecker is highly specialized to feed on wood-boring beetle larvae found under the bark of recently dead and dying trees. They use their specialized beaks, tongues, and other adaptations to access this abundant food source. While wood-boring beetle larvae make up the majority of their diet, they also supplement with other insects like ants and caterpillars. Black-backed woodpeckers play an important ecological role by regulating forest insect pests, accelerating nutrient cycling, and providing nesting habitat for other species. Their specialized insect-eating behavior is a key part of forest ecosystems across North America.