Forest Architects: Pileated Woodpecker & Scarlet Tanager Behavior

A Pileated Woodpecker works the base of a dying sugar maple in a Pennsylvania woodlot, excavating a rectangular cavity the size of a paperback book. Forty feet above, a Scarlet Tanager moves through the canopy in near silence, gleaning caterpillars from the underside of leaves the woodpecker will never reach. Same forest. Same morning. Completely different behavioral worlds — and together, a portrait of what large, intact temperate woodland actually does.

This isn't just about two charismatic species. Old-growth and mature second-growth forests across North America are under sustained pressure — from fragmentation, selective logging, climate-driven pest outbreaks, and development. Recent Audubon reporting on Alaska's Western Arctic frames a version of this challenge at continental scale: protecting the habitat structures that specific bird behaviors depend on. For Pileated Woodpeckers and Scarlet Tanagers, the behavioral stakes are local, legible, and worth understanding in detail.

What the Pileated Is Actually Doing

The Pileated Woodpecker (Dryocopus pileatus) is the largest woodpecker in North America at roughly 16–19 inches, and its foraging behavior is genuinely structural. This isn't incidental pecking. According to Cornell Lab of Ornithology's All About Birds, the species excavates deep, oblong cavities primarily to reach carpenter ant colonies (Camponotus spp.) and wood-boring beetle larvae inside dead or dying wood. A single foraging bout can produce a cavity large enough to destabilize a standing snag.

The behavioral sequence is worth slowing down to observe. A Pileated typically begins with a series of diagnostic taps — lighter, exploratory — before committing to full excavation. This isn't random. The bird is likely responding to acoustic feedback, sensing the hollow resonance of ant-riddled wood beneath the bark. Research on woodpecker foraging cognition, including work summarized by the Cornell Lab's Handbook of Bird Biology, suggests woodpeckers use multiple sensory cues to locate prey, including sound and possibly vibration detection through the bill.

Once committed, the excavation is forceful and directional — the bird follows the ant gallery inward, often exposing a vertical tunnel six inches or deeper. The chips that fall are diagnostic in the field: large, pale, rectangular. Fresh Pileated sign looks almost mechanical, like someone took a chisel to the wood.

Territory size is substantial. eBird range and abundance data shows Pileated Woodpeckers require large blocks of mature forest — pairs typically hold territories of 150–200 acres or more, though this varies by region and forest quality. Territorial behavior involves loud, rolling calls (wuk-wuk-wuk-wuk) and drumming on resonant dead wood, both of which carry considerable distance through closed canopy. When two territorial birds meet at a boundary, the interaction can escalate to slow, deliberate wing-spreading displays and bill-pointing — confrontational posturing that rarely becomes physical contact.

The Cavity Legacy

One behavioral consequence of Pileated foraging deserves particular attention: the cavities themselves become habitat. The American Bird Conservancy describes the Pileated as a keystone species precisely because its abandoned nest and roost cavities are subsequently used by Wood Ducks, Great Horned Owls, Eastern Bluebirds, and numerous small mammals. No other North American bird creates cavities of comparable size in standing dead wood.

Nesting behavior begins in late winter. Males initiate cavity excavation — a new cavity each year, typically in a large dead or partially dead tree — and drumming intensifies through February and March as pair bonds are reinforced. Both sexes excavate the nest cavity, and both incubate. According to Audubon's species guide, clutch size is typically three to five eggs, with an incubation period of roughly 18 days. Young Pileateds remain in the cavity for about a month before fledging, and the family group may stay loosely associated through summer.

The Tanager's Invisible Life

The Scarlet Tanager presents a behavioral contrast that is almost philosophical. Where the Pileated announces itself — loud, large, architecturally disruptive — the Scarlet Tanager is a canopy bird that most people hear far more often than they see.

The male's plumage is extraordinary: flame-red body, jet-black wings. But the species spends most of its time 40–80 feet up in the canopy of mature deciduous and mixed forest, moving methodically through the outer foliage. Cornell Lab's All About Birds describes its foraging as primarily gleaning — picking insects from leaf surfaces and stems — with occasional sallying to catch flying prey. During caterpillar outbreaks, particularly gypsy moth (Lymantria dispar) and forest tent caterpillar (Malacosoma disstria) events, Scarlet Tanagers have been documented foraging in concentrated bursts, working infested oaks and maples with unusual intensity.

The song — a burry, robin-like phrase often rendered as querit-queer-querit-queer — is the primary detection cue. It carries well through closed canopy and is given persistently by males through the breeding season. A useful field distinction: the call note, a sharp chip-burr, is distinctive and worth learning. Many experienced birders locate Scarlet Tanagers by call note before ever seeing the bird.

Forest interior dependency is a defining feature of this species. BirdLife International's assessment notes that Scarlet Tanagers are area-sensitive — they require large, unfragmented forest blocks for successful breeding. Edge effects, which increase nest predation and cowbird parasitism rates, push the species out of small woodlots even when habitat appears structurally suitable. A 10-acre woodlot simply doesn't function the same way as 500 connected acres, regardless of tree species composition.

Courtship and the Display Gap

Scarlet Tanager courtship behavior is understudied relative to the species' visual drama. Males arrive on breeding grounds before females and establish territories through song. When a female arrives, the male performs a display that involves spreading his wings to expose the black flight feathers against the red body — essentially maximizing the contrast of his plumage. Research on avian sexual selection suggests the brightness and saturation of the male's red carotenoid-based plumage may signal condition and foraging quality to prospective mates.

Female Scarlet Tanagers are olive-yellow — cryptic and easily overlooked — and handle most of the nest construction and incubation. The nest is a shallow cup, typically placed well out on a horizontal branch high in the canopy, making it genuinely difficult to locate. Both parents feed nestlings, and the male's continued presence near the nest is often the best behavioral cue that breeding is occurring in a given area.

Pileated courtship is comparably dramatic but differently structured. The mutual drumming and calling that intensifies in late winter functions as both pair-bonding and territorial advertisement simultaneously. Pairs that have held a territory across multiple seasons show high site fidelity — eBird multi-year data from established territories in the Appalachians and Great Lakes region reflects this consistency — returning to the same patches of old-growth and mature second-growth year after year.

What Behavioral Observation Reveals About Forest Health

These two species, read together, function as behavioral indicators of forest condition. A woodlot with active Pileated foraging has sufficient dead wood volume and large-diameter trees to support the species' energetic needs. A forest block with breeding Scarlet Tanagers has enough interior area and canopy continuity to buffer against the edge effects that suppress nesting success.

eBird's abundance maps show Scarlet Tanager populations concentrated in the Appalachians, the Ozarks, and the upper Midwest — wherever large, connected forest blocks persist. Breeding Bird Survey trend data compiled by the USGS indicates the species has experienced long-term population declines correlated with forest fragmentation on both breeding and wintering grounds.

For observers in the field, the practical insight is this: slow down at the boundary between alive and dead wood. Watch how a Pileated moves between foraging trees — it tends to work a patch systematically before moving on, and its flight path often reveals the distribution of suitable dead wood in a stand. Then look up. The same mature forest that supports Pileated foraging almost certainly has Scarlet Tanagers in the canopy, invisible unless you're listening for the burry song or the sharp chip-burr call note drifting down through the leaves.

The behaviors of both species are expressions of what old forest does. Understanding them — not just identifying the birds — is what transforms a walk through the woods into something closer to reading the landscape.