Bird in the Spotlight: Dunnock

4 September, 2025

By David Goodman

The Dunnock (Prunella modularis) is an unassuming little brown bird native to Europe and Western Asia. It is often grouped with the so-called “little brown jobs,” the cryptic little species that are sometimes only distinguishable by the most hardcore birders. Its name derives from the Old English dunnoc, meaning “little brown one,” making it arguably the first bird in English to be saddled with that dismissive epithet.

This rather majestic photo of a Dunnock is a testament to the power of a nice camera. Photo Credit: Daniel Jauvin.

Although superficially sparrow-like, the Dunnock belongs not to the sparrows but to the family Prunellidae, the accentors. Upon close inspection, the Dunnock is actually relatively easy to identify by its slender, pointed bill, in contrast to the sparrow’s heavier, seed-cracking beak. The Dunnock’s behavior is another clue as to its identity: they have a strong preference for ground foraging, and can usually be found skulking beneath hedgerows and bushes looking for seeds, worms, or bugs.

This decidedly less majestic photo of a Dunnock is a testament to the simple idea that it's hard to look impressive while under a bush. Photo credit: Josep del Hoyo.

The Dunnock has a notoriously complicated mating and social system. Both sexes defend territories, which is atypical among songbirds. Male territories are generally larger and often encompass those of multiple females. Within these overlapping ranges, the promiscuous Dunnock exhibits a remarkable variety of mating structures: simple monogamy (1 male + 1 female), polygyny (1 male + >1 female), polyandry (1 female + >1 male), and even polygynandry (multiple males and females sharing a territory) are all common. Males form an alpha / beta hierarchy in these structures, the same as wolves. Alpha males attempt to monopolize access to females, while beta males mate surreptitiously (and are encouraged to do so by the females).

As you can see in the chart above, polygynandry is sometimes just called “promiscuity,” especially in primatological contexts. I’m not sure why ornithologists chose the sterile and slightly alarming “polygynandry.” Maybe the primatologists are just more liberated.

Courtship involves a unique ritual in which the female crouches, spreads her wings, and fans her tail while raising her cloaca. The male then pecks at the cloaca, forcing the expulsion of sperm from previous mates and increasing his own chances of fertilization. Because females often mate with multiple males during a single breeding season, paternity is uncertain. Consequently, males provision chicks in proportion to their perceived likelihood of paternity, with each investing most heavily in nests where they believe their own offspring are present.

This graphic and potentially upsetting photo was taken by G.J. Gamble. Please direct all complaints to him.

Dunnocks are also frequent hosts of the Common Cuckoo (Cuculus canorus), a brood parasite that lays its eggs in the nests of other species. The result is often absurd: a diminutive Dunnock pair (or, in some cases, a coalition of males) toiling to feed a cuckoo chick many times larger than themselves. Despite the obvious disparity, the foster parents remain oblivious and continue feeding the cuckoo, even after it ejects the Dunnock’s own young from the nest.

That’s just not right. Photo Credit: Alan Leeks.

The species remains widespread across Europe, Western Asia, and parts of the Middle East, and is currently listed as Least Concern by the IUCN. Nevertheless, Dunnock populations have shown moderate declines through the 20th century, particularly in the UK, where increasingly “tidy” gardening and the removal of hedgerows reduce the dense cover this species depends on for foraging and nesting. Maintaining wilder hedgerows, brush piles, and structurally diverse gardens provides critical habitat for Dunnocks and will help ensure that they remain common across their range.

An engraving of the Dunnock by the famous English naturalist Thomas Bewick. Its title, winter “fauvette” (which means warbler in French), reflects French’s dominance as a language of culture and science in the 18th century. If it weren’t for Waterloo, “winter fauvette” could very well have been the title of this bird in the spotlight. 

The Dunnock is typical of a classic pattern in ecological science: visually uncharismatic species are sometimes among the most interesting. The world is full of beautiful swans that pair-bond for life, a beautiful testament to the power of oxytocin but not the most exciting mating structure. Meanwhile, the little brown bird that you probably mistook for a sparrow is living a life full of sexual intrigue. Sometimes it pays to investigate what those little birds are up to skulking under the bushes.