Wrens and nuthatches are two common backyard birds that often forage together in mixed flocks during the winter. But are these busy little birds actually related? The short answer is no – wrens and nuthatches belong to completely different bird families.
Wrens are small, energetic songbirds in the family Troglodytidae. There are around 80 species of wren worldwide, mostly residing in the Americas. Nuthatches belong to the Sittidae family of small songbirds. There are about 25 species of nuthatch found throughout North America, Eurasia, and the Middle East.
Differences Between Wrens and Nuthatches
While wrens and nuthatches may look similar to the casual observer, there are several key differences between these two bird families:
Physical Features
Wrens are tiny, plump birds with short, stubby bills. They have rounded wings and cocked tails that they often bob up and down. Wrens range in size from the tiny marsh wren at just 10 cm long to the 20 cm long giant wren of South America.
Nuthatches have more elongated bodies and long, straight bills. Unlike wrens, they have short tails. Nuthatches range in size from 8 cm long (pygmy nuthatch) to 24 cm long (giant nuthatch).
Habits
Wrens are extremely active foragers that hop along branches or rummage through leaf litter in search of insects and spiders. They builds domed nests in cavities or hidden in thickets.
Nuthatches move more deliberately as they methodically probe tree bark crevices for hidden insects. They are famous for their ability to head down tree trunks with ease. Nuthatches nest in holes in dead trees or crevices in bark.
Geographic Range
Most wren species live in the Americas, especially the tropics. Just two species, the Eurasian wren and winter wren, inhabit temperate regions of Europe and Asia.
Nuthatches have a wider distribution across North America, Europe, and Asia. The majority live in northern temperate forests. Several species inhabit rocky subtropical habitats.
Vocalizations
Wrens are famous for their complex, melodious songs. They sing year-round, with especially elaborate dawn songs used for defending territory and attracting mates.
Nuthatches use simple repeated calls like their namesake “yank-yank” to stay in contact with their mate or signal alarm. Their calls are nasal and often sound like squeaks or trumpets.
Taxonomy and Evolutionary Relationship
Wrens and nuthatches are not closely related despite some superficial similarities in appearance and habits. They belong to separate taxonomic families:
- Wrens – Family Troglodytidae
- Nuthatches – Family Sittidae
These two bird families are part of different taxonomic orders:
- Wrens – Order Passeriformes (perching birds)
- Nuthatches – Order Passeriformes (perching birds)
While wrens and nuthatches both belong to the diverse order Passeriformes, this order contains over 5,000 species of songbirds. Perching birds diverged evolutionarily over 50 million years ago into many distinct families.
Wrens are most closely related to other primitive insect-eating songbirds like gnatcatchers, dippers, and thrashers. Nuthatches are more closely related to treecreepers, another family of birds that forage on tree trunks.
Here is a phylogenetic tree showing the approximate evolutionary relationships between wrens, nuthatches, and related songbird families:
Taxonomic Order | Family | Example Genera |
---|---|---|
Passeriformes | Muscicapidae (Old World Flycatchers) | Muscicapa, Ficedula |
Passeriformes | Certhiidae (Treecreepers) | Certhia |
Passeriformes | Sittidae (Nuthatches) | Sitta |
Passeriformes | Troglodytidae (Wrens) | Troglodytes, Campylorhynchus |
Passeriformes | Polioptilidae (Gnatcatchers) | Polioptila |
As you can see, wrens and nuthatches occupy completely different branches of the passerine family tree despite some ecomorphological similarities related to their lifestyles.
Ecological Similarities Between Wrens and Nuthatches
While not closely related, wrens and nuthatches have evolved some comparable physical and behavioral adaptations as small insectivorous birds that forage on trees.
Foraging Behaviors
Wrens and nuthatches both use short, straight bills to probe into crevices and under bark for hidden insects. Nuthatches pry apart bark with their bills or jam large seeds into crevices as wedge tools to excavate prey.
Both birds move actively from branch to branch and up and down trunks while foraging. Nuthatches frequently hang upside-down underneath branches.
Social Habits
Wrens and nuthatches often join mixed winter foraging flocks with chickadees, titmice, woodpeckers, and other species. These flocks help spot food sources and provide protection from predators.
Both species are territorial during the breeding season, when they separate into pairs. But they tolerate conspecifics (members of the same species) during winter flocking.
Nest Sites
Wrens and nuthatches nest in cavities, either natural holes or abandoned woodpecker holes. Their nest sites provide protection from predators and insulation from weather.
Wrens may also nest in sheltered thickets or shrubs. Both use mud or feces to reduce the cavity entrance size.
Similar Backyard Birds
For casual observers, wrens may be confused with nuthatches when they associate in mixed foraging flocks around backyard feeders. But on closer inspection, several features distinguish these families:
Carolina Wren vs. White-breasted Nuthatch
- Carolina wrens are plumper with long, barred tails; white-breasted nuthatches have more sleek bodies and short tails.
- Carolina wrens creep along branches; nuthatches walk smoothly down trunks head-first.
- Carolina wrens have loud, ringing songs; nuthatch calls sound like nasal yells.
- Carolina wrens prefer nesting in shrubs or vine tangles; nuthatches nest in tree cavities.
House Wren vs. Red-breasted Nuthatch
- House wrens are brown above with barred wings and tail; red-breasted nuthatches have bluish-gray backs and black eyestripes.
- House wrens ping around branches quickly; red-breasted nuthatches descend trunks methodically.
- House wrens sing exuberant cascades of trills; red-breasted nuthatches utter nasal, piping calls.
- House wrens nest in cavities and odd spaces around buildings; red-breasted nuthatches nest in dead trees.
Conclusion
While wrens and nuthatches may flock together and have some ecological similarities, they are actually quite unrelated bird families. Wrens belong to an ancient oscine songbird family, while nuthatches are part of a more modern tree-foraging group.
Careful observation of body shape, behavior, songs, and nesting habits helps distinguish between these two types of small acrobatic birds at backyard feeders. Probing their evolutionary history reveals they are only distant cousins in the diverse perching bird order.