Bogota’s Rufous-Collared Sparrows

The Rufous-collared Sparrow is one of Bogota’s most familiar birds. Known locally as the copeton, meaning roughly “the crested one,” the small brown-and-gray bird takes its Colombian name from the short crest of feathers found on the male’s head, called a copete. It lives in gardens, parks, grasslands and other open spaces across the city and the surrounding Sabana de Bogota.

But people who remember hearing its calls throughout the day have noticed a change. The species has declined in the Bogota region, according to long-term bird counts, although it remains common and is not considered threatened nationally.

A 2017 study by ornithologists F. Gary Stiles, Loreta Rosselli and Susana De La Zerda examined 26 years of Audubon Christmas Bird Counts, covering Bogota and parts of the surrounding savanna from 1989 to 2014. The researchers found that population numbers remained stable through much of the period before declining in the later years.

The causes are more complicated than a single environmental threat.

A familiar bird with an unusually large range

The Rufous-collared Sparrow (Zonotrichia capensis) is not restricted to Colombia. Its range extends from southeastern Mexico through much of Central and South America to Tierra del Fuego.

It generally favors open or semi-open habitats. Grasslands, cultivated areas, gardens, and parks can all provide suitable habitat, which helps explain its long association with Bogota.

The bird is about 14 centimeters (5.5 inches) long and feeds mainly on seeds and insects. The species is classified as Least Concern globally, and Colombian environmental references do not place it in a national threat category.

That status is important. A decline around Bogota does not mean the species is approaching global extinction.

The decline followed years of relative stability

The 2017 study found no statistically significant change in copeton abundance between 1991 and 2009. The later part of the series showed a significant decline.

The researchers considered several factors affecting the region’s bird populations, including urbanization, changes in vegetation and wetlands, interactions between species, and rising temperatures. For the copeton specifically, they suggested that brood parasitism by the Shiny Cowbird (Molothrus bonariensis) may have been the main factor behind its recent decline, with urbanization playing a lesser role.

Shiny Cowbirds lay their eggs in the nests of other birds. The host parents then incubate the eggs and raise the chicks. During informal observations on the Universidad Nacional campus in 2013 and 2014, Stiles recorded more pairs of copetones feeding fledgling cowbirds than their own young.

Another possible explanation is predation by the Great Thrush (Turdus fuscater), known locally as the mirla. The species can prey on Copeton nestlings and fledglings. The researchers concluded that predation was unlikely to explain the recent decline because copeton numbers had remained stable for years while the thrush population was increasing.

Bogota has changed around the copeton

Urban growth has altered the habitats where the species feeds and nests. The 2017 study documented the conversion of pastures and agricultural areas to housing, commercial buildings, and greenhouses. The study links the loss of suburban gardens to rising apartment density, identifying diminished green space as a key driver of stress for species like the copeton.

Changes to Bogota’s wetlands have also affected bird communities. Some interventions created new open-water areas or expanded vegetation, while others reduced water supplies or altered the habitat available to birds.

Climate change adds another layer. During the 1989–2014 study period, the average annual temperature at Bogota’s El Dorado airport increased by 0.65°C, while the average annual minimum temperature rose by almost 2°C. The researchers linked many changes in the region’s bird community to warming and the city’s urban heat island.

Climate change, however, was not presented as the sole explanation for the copeton’s decline. The study found that several pressures operated simultaneously.

The copeton has a local accent

One of the most unusual features of the species is its song. Male Rufous-collared Sparrows do not sing the same way everywhere, and scientists have documented geographical variation in their songs, including differences in the structure and speed of the final trill.

Studies on Argentine populations show these vocal variations form distinct dialects tied to specific habitats. The patterns can remain stable for decades, and researchers have linked some of the variation to the acoustic properties of grasslands, scrub, and forests.

The song typically features a series of whistles followed by a trill. While individual birds develop unique calls, specific trill patterns identify a bird’s origin.

Bogota’s environmental authorities also maintain recordings of the copeton and describe its vocalizations, which include whistles and trills.

The scientific literature does not establish that Bogota’s copetones have a uniquely defined dialect comparable to the extensively studied dialect zones of Argentina. What is established is that the species has geographically variable songs, making vocal differences one of its unusual biological characteristics.

It has not disappeared from Bogota

The copeton remains a familiar species in the capital. Bogota’s environmental authorities describe it as an emblematic local bird found in gardens, parks, grasslands, wetlands, and the Eastern Hills.

The evidence points to a more specific change: a once-stable local population declined during the later years of a long-term monitoring series, while the city and its surrounding habitats continued to change.

That distinction became important enough for Colombia’s Inspector General’s Office, the Procuraduria General de la Nacion, to request information in 2024 from national and local environmental authorities about possible declines in the copeton and other birds in the Bogota savanna. The agency asked whether significant population reductions or threats existed and what protection measures might be required.

For a bird so closely associated with Bogota, fewer sightings and quieter mornings are easy to notice. The scientific record points to several pressures, with brood parasitism and habitat changes standing out for the copeton itself. Climate change is part of the larger transformation of the region’s bird community, but it is not a sufficient explanation on its own.

The copeton is still there. The question is how much of the landscape it once occupied will remain suitable for it.