The downy woodpecker is a small bird that can be found across most of North America. With their distinctive black and white plumage, downy woodpeckers are a familiar sight in backyards, parks, and forests. Though small, these energetic birds play an important role in many ecosystems as primary cavity nesters that provide nesting sites for other birds. But what sustains the downy woodpecker and allows it to fulfill this crucial ecological niche? The answer lies in understanding the downy woodpecker’s feeding habits and preferred food sources.
Insects as a Primary Food Source
The downy woodpecker is considered an omnivorous bird that eats a varied diet including seeds, nuts, berries, sap, and some plant material. However, the mainstay of the downy woodpecker’s diet consists of insects and other arthropods such as spiders. This concentration on insect prey provides the high-protein food that allows downy woodpeckers to breed, nest, and raise chicks successfully.
Several studies have shown that insects and other arthropods can make up 50-90% of the downy woodpecker’s annual diet. During the summer breeding season when protein requirements are highest, the percentage of insects in their diet can reach as high as 90%. Some key insect groups consumed include:
- Beetles
- Ants
- Caterpillars
- Flies
- Spiders
- Crickets
- Grasshoppers
Downy woodpeckers use their sharply chisel-like bill to hammer into trees and deadwood to access boring insects and larvae located underneath the bark or in shallow wood crevices. Their specialized tongue can then spear and extract the insects. This ability to excavate into wood gives downy woodpeckers an advantage over other bird species in accessing wood-bound insects.
Adaptations for Insect Foraging
Downy woodpeckers possess physical and behavioral adaptations that allow them to take advantage of insects as a prime food source:
- A strong, chisel-like bill to hammer into wood
- A long, barbed tongue to remove insects
- Sharp claws that can grip bark
- Stiff tail feathers that provide support against tree trunks
- Hunting behavior that involves methodically probing into bark and excavating shallow holes in search of concealed insects
These adaptations allow downy woodpeckers to access a food source – wood and bark-bound insects – that is not as readily available to other birds like warblers and flycatchers that feed on more exposed insects. The downy woodpecker’s specialization allows it to occupy its niche even in competition with other woodpecker species.
The Importance of Trees
Since insects that burrow into living and dead trees are such an important food source, the availability of woodland habitats with adequate trees is key to sustaining healthy downy woodpecker populations. These birds are particularly dependent on forested environments that provide:
- An abundance of insect prey – especially beetle larvae
- Dead trees and fallen logs that are prime locations for insects
- Live trees and snags that host carpenter ants and other colonial insects
A diversity of tree species, tree age, and conditions also supports insect variety that downy woodpeckers can take advantage of. Old growth forests with natural processes of decay and regeneration are especially valuable.
In more urban and suburban areas, downy woodpeckers can adapt to living in wooded parks, backyards, golf courses, and other locations with trees – especially if some standing dead trees or snags are left intact. Providing suet feeders with insect-based suet can also help supplement their diet.
Other Food Sources
While insects make up the bulk of their diet, downy woodpeckers will consume other food items depending on seasonal availability:
- Seeds and Nuts – Usually eaten in fall and winter and include acorns, beech nuts, hickory nuts, and seeds of weeds and grass.
- Fruit and Berries – Downy woodpeckers enjoy berries and fruits of dogwood, serviceberry, sumac, hackberry, and others.
- Tree Sap – These birds will drink sap from wells excavated in trees by sapsuckers.
- Suet – Downy woodpeckers will frequent suet feeders, especially in winter.
- Human Food – They may visit back yard feeders with bread, peanuts, corn, and sunflower seeds.
However, these supplementary foods do not provide the high protein and nourishment that insect prey offers. While visiting feeders is common behavior, a downy woodpecker’s survival still depends on adequate insect availability.
Importance of Insects to Nestlings
The protein derived from insects is especially crucial during spring and summer when downy woodpeckers are raising their young. According to Cornell Lab of Ornithology, adult pairs can feed nestlings hundreds of times per day once they hatch – almost exclusively on insect prey.
Some key facts about how insect availability affects nesting success:
- Abundant insects near the nest are key so parents can efficiently gather food.
- Nestlings may consume up to 500 insects per day for adequate nutrition.
- Main insects fed to young include caterpillars, beetles, ants, grasshoppers and crickets.
- In years of insect scarcity or bad spring weather, survival of nestlings drops.
Access to plentiful insects lan early spring is vital for downy woodpecker pairs to successfully raise a clutch of chicks.
Conclusion
While downy woodpeckers are considered omnivores and enjoy various seeds, nuts, and fruits, insects and other arthropods clearly make up the bulk of their diet year-round. The abundance of insect prey in forested habitats across North America allows the downy woodpecker to flourish as it excavates into trees to access borers, carpenter ants, beetle larvae, and other wood-bound insects. This specialization sets the downy woodpecker apart from other birds and is key to its breeding success and ability to proliferate. Efforts to support downy woodpecker populations in urban, suburban, and woodland habitats must focus on sustaining sufficient insect diversity and availability. By supporting robust insect populations, adequate dead wood, and snags, we enable this unique woodpecker to thrive and provide essential ecological services. The downy woodpecker illustrates the interconnectedness and interdependence characteristic of the natural world.