Brown Creepers are small, well-camouflaged birds that live in woodlands and forests across North America. They have a very specialized diet consisting primarily of insects and spiders that they find hiding in the bark of trees.
Quick Answer
Brown Creepers eat insects, spiders, and other small invertebrates that they find under loose tree bark. Their main prey items include beetles, moths, flies, ants, aphids, and spiders. They use their long, curved bills to probe and pry off bark to expose hiding insects.
What does the Brown Creeper’s Diet Consist of?
The Brown Creeper has a very specialized diet that relies heavily on finding insects and other invertebrates hiding in tree bark. Here are some details on their main prey items:
- Beetles – Various species of beetles and their larvae account for around 50% of the creeper’s diet. Their favorite beetles include bark beetles, longhorn beetles, and weevils.
- Moths and Caterpillars – Brown Creepers eat a variety of moth and butterfly larvae that they find burrowing under bark. Adult moths are also occasionally eaten.
- Flies – Fly larvae living under bark are an important part of the creeper’s diet. They also sometimes eat adult flies like midges and barkflies.
- Spiders – Bark-dwelling spiders and their egg sacs provide a nutritious source of food for Brown Creepers.
- Ants – Carpenter ants and other wood-dwelling ants are frequently eaten by Brown Creepers.
- Aphids – These sap-sucking insects cling to the bark of trees in large colonies which provide an easy meal for creepers.
The Brown Creeper uses its slender, curved bill to probe, pry, and peel away bark in search of concealed insects and spiders. The unique shape of its bill helps it excavate and explore cracks and crevices that most other birds cannot access. It uses the tip of its bill like a pair of tweezers to pluck insects and spiders out of hiding.
Where Does the Brown Creeper Find its Food?
Brown Creepers forage for food on the trunks and branches of a variety of tree species including oaks, maples, hickories, hemlocks, pines, and many others. They move up the trunk in a spiral searching pattern, using their stiff tail feathers for support as they inch along. This allows them to scan and explore every bit of bark in their path, picking off any insects or spiders they uncover.
They tend to forage most actively on trees with lots of cracks, crevices, and loose, peeling bark that provides good hiding spots for insects. Some of their favorite bark types include:
- Rough, shaggy bark – Provides excellent crevice habitat like oak, hickory, ash trees
- Loose, peeling bark – Easy for Brown Creepers’ bills to pry up like sycamore, pine, cedar trees
- Furrowed bark – Deep grooves offer hiding spots, such as mature maples and elms
In addition to tree trunks, Brown Creepers will also forage along large branches, often venturing farther out from the main trunk than most other bark foragers. They occasionally glean insects and spiders from small twigs as well.
How does the Brown Creeper Hunt?
The Brown Creeper is uniquely adapted for seeking out and capturing insects and spiders hiding in bark crevices. Here is an overview of its specialized hunting strategy and techniques:
- Methodical, Spiral Foraging Pattern – Brown Creepers methodically scan tree trunks in an upward spiral searching pattern, using their stiff tails as a prop. This allows them to systematically examine and probe the bark from the bottom to the top of the tree.
- Stealthy, Camouflaged Approach – Their mottled brown and white plumage serves as excellent camouflage against tree bark. Creepers are very quiet and stealthy as they creep up tree trunks, allowing them to sneak up on prey.
- Prying with Curved Bill – They use their slender, decurved bill to carefully pry, flake, and peel back pieces of bark to expose hidden insects and spiders. The tip of the bill can be inserted into very narrow crevices.
- Gleaning and Probing Motions – Once bark is peeled back, they use quick gleaning motions and probing jabs with their bill to grab prey. Their bill tip functions like tweezers to pluck out bugs.
- Thorough Excavation – Brown Creepers are very persistent and will excavate holes in bark and use acrobatic contortions to access deep crevices where prey may be hiding.
Brown Creepers also have very sharp vision to help spot tiny prey under low light conditions. And their curved claws help them cling to bark surfaces as they scour tree trunks and branches upside-down.
What Adaptations Help the Brown Creeper Find Food?
Brown Creepers have several physical and behavioral adaptations that allow them to access food resources that most other birds cannot:
- Specialized Bill Shape – The slender, curved bill is perfectly shaped for prying under bark and probing into crevices.
- Stiff Tail Feathers – They use their stiff tail feathers like a prop or extra leg to brace themselves upright on vertical surfaces.
- Camouflage Plumage -Their streaked brown-and-white plumage helps them avoid detection by prey against tree bark.
- Sharp Claws – Curved claws allow them to cling to rough bark and avoid falling as they forage acrobatically along branches and trunks.
- Acute Vision -They have excellent vision that allows them to pinpoint tiny insects and spiders hidden in dark crevices.
- Spiral Foraging Method – Their unique upward spiral searching pattern lets them efficiently cover every inch of bark on tree trunks.
These physical and behavioral adaptations allow Brown Creepers to take advantage of an abundant but hard-to-access food source – insects and spiders hiding under tree bark. Other species cannot exploit this niche as effectively as the highly specialized Brown Creeper.
What Kinds of Habitats do Brown Creepers Forage In?
Brown Creepers occupy mature forests across much of North America. They forage for food in a variety of woodland and forest habitats including:
- Deciduous Forests – Forage among oak, maple, beech, hickory, ash, elm trees.
- Coniferous Forests – Feed on pine, spruce, fir, cedar, hemlock trees.
- Mixed Forests – Utilize both deciduous and coniferous tree species.
- Woodlots – Small stands of trees in rural areas surrounded by fields or developments.
- Parklands – Scour park trees in urban and suburban areas.
- Riparian Areas – Feed along stream courses and rivers lined with cottonwoods and other trees.
Mature forests with large, old trees that have deeply furrowed or loose peeling bark tend to be their most productive foraging areas. But they will use any habitat with a good supply of live and dead trees.
When are Brown Creepers Most Active?
Brown Creepers are active little birds that forage in a perpetual motion, pausing only briefly to pry up bark and grab prey. Here are some notes on their activity patterns:
- All Day Activity – Forage actively from dawn to dusk on most days.
- Cold Temperature Tolerance – Remain active down to very frigid temperatures below 0 °F (-18 °C).
- Year-Round Foraging – Maintain their cryptic foraging strategy through all seasons.
- Frequent Movement – Travel constantly in search of good foraging trees.
- Territorial in Winter – The males defend winter foraging territories.
- Non-Territorial in Summer – Range widely without distinct territories when breeding.
Brown Creepers are highly active foragers that keep on the move throughout the year, except at night when they roost. Their ability to withstand cold temperatures allows them to take advantage of plentiful winter food sources on trees when insects are scarce.
Do Brown Creepers Drink Water?
Brown Creepers get most of the water they need from their food sources – juicy insects and spiders. But they will also drink free water when it is available:
- Drinking from Dew – Lick water droplets from leaves and bark early in the morning.
- Drinking from Streams – Sip and bathe in shallow stream edges.
- Seasonal Drinking – More likely to drink open water in hot summer months when dehydrated.
- Drinking from Rain – Catch falling raindrops during showers.
Since they get pre-formed water from prey, they do not typically need to drink as frequently as seed-eating birds. But when accessible, drinking water likely provides added hydration benefits for Brown Creepers.
Do Brown Creepers Eat Anything Besides Insects and Spiders?
The Brown Creeper is a specialist when it comes to food. Insects and spiders make up over 99% of its diet. But on very rare occasions, they have been observed consuming other food items:
- Seeds – May eat small seeds like birch seeds if insect food is scarce.
- Sap – Occasionally drink maple sap or pine pitch for nutrients.
- Fruit – May sample the occasional berry such as poison ivy.
- Suet – Backyard suet feeders may attract winter creeps but are not a significant food source.
These alternative foods likely make up less than 1% of their total diet. So the Brown Creeper remains an extreme bark insect and spider specialist the vast majority of the time.
Do Brown Creepers Feed at Bird Feeders?
Brown Creepers very rarely visit backyard bird feeders because they are specialized to feed on tree bark, not seeds or suet. However, you might occasionally see one at feeders for the following reasons:
- Suet Feeders – They may very rarely nibble on suet as an alternative food in winter.
- Bird Baths – Can provide drinking and bathing water.
- Accidental Visits – Young creepers may briefly land on feeders out of curiosity.
- Nearby Foraging – May forage on trees close to feeders but ignore the feeders themselves.
While feeders do not provide their natural food sources, Brown Creepers appreciate nearby trees and any water sources. But overall, they are one of the least likely forest birds to visit backyard feeders specifically.
What Eats Brown Creepers?
The Brown Creeper faces predation risks from a variety of larger birds and mammals. Some of its most common natural predators include:
- Accipiter Hawks – Sharp-shinned Hawks and Cooper’s Hawks are agile woodland hunters of small songbirds like creepers.
- Falcons – American Kestrels sometimes grab creepers from tree trunks.
- Owls – Barred Owls and other woodland owls prey on creepers at night.
- Woodpeckers – Larger woodpecker species like Pileated occasionally prey on creepers.
- Jays – Blue Jays may raid creeper nests for eggs and nestlings.
- Squirrels – Red and gray squirrels take eggs and nestlings.
- Chipmunks – Primarily threaten eggs and young in the nest.
- Snakes – Some arboreal snakes like rat snakes climb trees to take creepers.
The camouflaged Brown Creeper attempts to avoid predators by staying hidden against tree bark as it climbs. But when forced to fly between trees it is vulnerable, especially crossing openings and clearings.
Do Brown Creepers Migrate?
Most populations of Brown Creepers in Northern parts of North America migrate short distances each year. Their migration patterns include:
- Northern Breeders – Canadian creepers and those from the northern U.S. migrate south each winter.
- Southern Residents – Populations in the southern U.S. and Mexico are mostly year-round residents.
- Short-Distance Migration – They generally migrate only far enough to find suitable wintering habitat.
- Earlier Fall Movement – They start moving south relatively early, from September to November.
- Later Spring Return – Head back north to breeding grounds between March and May.
Migrating Brown Creepers travel at night and use forested stopover sites to rest and feed during the daytime. They often arrive on their wintering grounds before other migratory songbirds.
Where do Brown Creepers Nest?
Brown Creepers nest in tree cavities and behind loose bark on trees. Favorite nest sites include:
- Rotten Knotholes – Hollowed out cavities in dead tree knots.
- Woodpecker Holes – Old cavities made by woodpeckers.
- Loose Bark – Nests built under curled bark that has peeled away from the trunk.
- Tree Hollows – Small hollow areas on the inside of a living or dead tree.
- Nest Boxes – Will sometimes use nest boxes designed for chickadees and other small birds.
The female builds the nest out of twigs, bark, moss, spider egg sacs, and other materials. Nest height can range from just a few feet above ground to over 50 feet high. Rotting dead trees (snags) provide ideal natural nest sites.
What is the Brown Creeper’s Breeding Season?
Brown Creepers mate and nest relatively early in the spring. The timing of breeding activities includes:
- April to July – Nesting season ranges from early spring through mid summer.
- Late March – Females begin building nests.
- April to May – Egg laying peaks.
- May to June – Most chicks hatch.
- June to July – Juveniles fledge from the nest.
They often raise just one brood per year. Males maintain and defend nesting territories early on but both parents help feed the chicks. The female alone incubates the 4-8 eggs for about 2 weeks.
How Many Eggs do Brown Creepers Lay?
Typical Brown Creeper clutch sizes include:
- 4 to 8 eggs per clutch
- 6 eggs – Average clutch size
- 1 brood per year – Usually raise just one clutch annually.
- 12 days – Average incubation until hatching
- 16-17 days – Nestling period until fledging
The female lays one egg per day. She has a brood patch for incubating the eggs. Both parents feed the hatchlings. The chicks are able to leave the nest at around 3 weeks old.
What do Brown Creeper Chicks Eat?
Brown Creeper chicks hatch helpless with eyes closed. At first, the parents feed them regurgitated insects and spiders. As they grow, the diet of the nestlings includes:
- Regurgitated Insects – Adult creepers bring beakfuls of softened insects to the young.
- Small Caterpillars – A prime food source for growing chicks.
- Spiders – Parents bring back small, soft-bodied spiders.
- Insect Larvae – Beetle and moth larvae are fed to nestlings.
- Flying Insects – Able to capture flies once coordination develops.
The chicks grow quickly and are ready to leave the nest at 16-18 days old. Just before fledging, the parents may bring whole insects for the chicks to practice handling.
Do Both Parents Feed the Young?
Yes, both male and female Brown Creepers share duties feeding nestlings:
- Equal Workload – Males and females deliver food equally.
- Constant Foraging – Adults make frequent trips to find food for the chicks.
- Up to 96 Feedings a Day – Nestlings may be fed over 90 times daily.
- Frequent Feedings – Parents deliver small meals almost continuously from dawn to dusk.
The male also continues to provision the female while she incubates eggs. Both parents are critical for successfully raising their demanding brood.
What is the Brown Creeper’s Song?
The Brown Creeper’s song is a very high-pitched, thinning, warbled trill. It has been described as sounding like a squeaky wheelbarrow wheel. The song features:
- Fading Trill – A short series of notes that starts abrupt but rapidly descends and fades out.
- Very High Pitch – The trilled song reaches up to 10 kHz in frequency.
- Soft Volume – Song can be difficult for humans to hear.
- Squeaky Quality – Vocalization has a squeaky, whining quality.
- Territorial Function – Males sing to proclaim nesting territories.
The Brown Creeper’s nasal, wheezy song is mostly heard during their breeding season when males are defending territories. It carries only short distances.
What are some Interesting Facts about Brown Creepers?
Here are a few fascinating facts about the unique Brown Creeper:
- They are the only North American birds with stiff tail feathers adapted for creeping up tree trunks.
- Their bills have curved downward tips and specialized bristles for probing into crevices.
- They build camouflaged nests lined with spider egg sacs under loose bark or in cavities.
- Males and females are monomorphic – they look identical.
- They have one of the smallest body sizes of any songbird in North America.
- Brown Creepers rarely visit bird feeders – they eat only insects and spiders.
- They breed very early and can survive harsh northern winters.
- Their population numbers are actually increasing across most of North America.
Conclusion
In summary, the Brown Creeper is a fascinating bird that is uniquely adapted for foraging on tree trunks for insects and spiders. Their specialized bill shape, stiff tail, camouflage, and other traits allow them to exploit food resources that most other birds cannot. They play an important role controlling forest insect populations. While creepers can be cryptic and hard to spot, observing their behavior and ecology provides insights into their success as highly efficient bark gleaners.
