White-lined Tanager: A Jewel of the Tropical ForestImagine a bird with a striking black plumage decorated with intricate white markings, contrasting sharply with its fiery red eyes. That’s the White-lined Tanager, a small and charming bird that inhabits the tropical forests of South America.
This article aims to provide an overview of the species, focusing on its identification, plumages, and molts. Whether you are an amateur birdwatcher or simply fascinated by the marvels of nature, join us to discover the beauty and uniqueness of this lovely bird.
Identification
The White-lined Tanager is a passerine bird in the family Thraupidae. It is about 14 cm (5.5 in) long, with a wingspan of about 23 cm (9 in) and an average weight of 11 g (0.4 oz).
As its name indicates, the most distinctive feature of this bird is the white line that runs from the base of the bill, over the eye, and down the cheek. The rest of the plumage is black, except for a small white patch on the wing-coverts and some rufous feathers on the sides of the breast and under the tail.
The bill is pointed and slightly curved downward, while the legs are rather short and pink or orange. Males and females have similar plumage, but juveniles are duller and lack the white markings.
Field
Identification
To identify the White-lined Tanager in the field, you should look for the white line and the black plumage. The red eyes are also conspicuous, especially when the bird faces you.
However, this species can be confused with other birds that have similar colors or patterns, such as the Black-capped Tanager (Tangara heinei), which has a black cap and a more conspicuous rufous patch on the side of the neck, or the Black-goggled Tanager (Trichothraupis melanops), which has a black face with a white patch behind the eye and a yellow-green body. It’s important to check the habitat, behavior, and vocalizations to confirm the identification.
Similar Species
Another bird that can be easily confused with the White-lined Tanager is the White-shouldered Tanager (Tachyphonus luctuosus), which has a similar size and shape, but a different color pattern. The White-shouldered Tanager has a black head and upperparts, with a white shoulder and a bright red belly.
The bill is also longer and more curved than in the White-lined Tanager. Sometimes, the two species may hybridize, producing intermediate plumages that can be challenging to identify.
Plumages
The White-lined Tanager has two basic plumages: the basic or definitive plumage and the juvenile or first-winter plumage. The basic plumage is acquired through a complete or gradual molt that occurs after the breeding season, usually from April to August.
The molt process takes about 50-60 days, during which the bird replaces all its feathers. The adult male and female have similar plumages, but males may have slightly brighter or larger white markings.
The basic plumage of the White-lined Tanager may differ slightly among populations, especially in the intensity of the black color and the size and shape of the white markings. However, these differences are not consistent enough to recognize subspecies.
Juveniles or first-winter birds have a duller and browner plumage, with faint or incomplete white markings. They resemble the female but lack the rufous feathers on the sides of the breast and under the tail.
Juveniles retain this plumage until they undergo their first partial molt, usually in their second or third year of life.
Molts
The White-lined Tanager has a complex molt strategy that varies according to the age, sex, and reproductive status of the bird. The basic or definitive molt, as mentioned before, is a complete or partial replacement of all the feathers before the non-breeding season.
The timing and duration of this molt depend on the photoperiod, hormonal and nutritional cues, and other factors that regulate the bird’s metabolism and physiology. Apart from the basic molt, the White-lined Tanager may undergo other molts, such as the prebasic or prealternate molt, which is a partial molt of specific feathers that occur before the breeding season.
This molt usually affects the head, breast, and body feathers, and is more evident in males than females. The prebasic molt allows the bird to acquire a fresh and colorful plumage for the courtship season, enhancing their attractiveness to potential mates.
Conclusion
The White-lined Tanager is a fascinating bird that combines simplicity and elegance in its plumage, behavior, and vocalizations. Despite its widespread distribution and relative abundance, this species faces several threats, such as habitat loss, fragmentation, and hunting.
It’s essential to raise awareness about the conservation needs of this and other tropical birds, promoting sustainable practices that preserve the natural heritage for future generations. If you have the chance to watch a White-lined Tanager in the wild, don’t miss it, and remember that every bird counts in the colorful mosaic of life.
Systematics History
The White-lined Tanager (Tachyphonus rufus) is a small bird species belonging to the family Thraupidae, order Passeriformes. The taxonomic history of this bird has been characterized by several changes in its generic and specific names, reflecting the evolution of ornithological knowledge and the emergence of new methods and concepts.
The earliest scientific reference to the White-lined Tanager appears to be the description by Linnaeus (1758) of a specimen from Cayenne, French Guiana, as Emberiza rufa. Subsequent taxonomic revisions by various authors have led to the existing nomenclature, which recognizes Tachyphonus as the genus name and rufus as the species name.
In this section, we will review the geographic variation, subspecies, and related species of the White-lined Tanager.
Geographic Variation
The White-lined Tanager has a wide distribution in South and Central America, encompassing a range of tropical and subtropical habitats, from humid forests to dry savannas and semi-open areas. The species occurs from eastern Panama to eastern Brazil and northern Argentina, with isolated populations in Trinidad and Tobago.
Within this range, the White-lined Tanager shows noticeable geographic variation in plumage, size, and vocalizations, reflecting the effects of isolation, selection, and adaptation. The geographic variation has been studied by various methods, such as morphometrics, bioacoustics, and molecular genetics, revealing some interesting patterns and hypotheses.
Subspecies
The White-lined Tanager has been traditionally divided into several subspecies based on differences in plumage, size, and habitat. However, the subspecific taxonomy of the species is still debated, and some authors have proposed alternative schemes or questioned the validity of some subspecies.
Here we present a summary of the most widely recognized subspecies. T.
r. rufus: The nominate subspecies occurs in eastern Panama and northern Colombia.
It has black plumage, with a large white line from the bill to the ear-coverts, a small white wing-spot, and reddish-brown flanks and undertail coverts. T.
r. variegatus: This subspecies occurs in western Colombia and Ecuador.
It has similar plumage to rufus but has a smaller wing-spot and less distinct flanks. T.
r. caucae: Found in western Colombia, this subspecies has a slightly smaller body and shorter wings and tail than rufus.
Its plumage is also darker and duller, with a thin white line and a buffy wash on the belly. T.
r. melanopeplus: This subspecies occurs in northeastern Colombia and Venezuela.
It has a blacker plumage than rufus and a more extensive white line that reaches the nape. It also has a dark throat and a smaller wing-spot.
T. r.
oleagineus: This subspecies occurs in northern Venezuela. It has a dark plumage similar to melanopeplus but with a wider white line.
It also has a large wing-spot and reddish flanks and undertail coverts. T.
r. trinitatis: This subspecies occurs in Trinidad and Tobago.
It has a black plumage similar to rufus but with a broader and more diffuse white line. It also has a small yellowish wing-spot and rufous flanks.
T. r.
uropygialis: This subspecies occurs in eastern Venezuela, Guyana, Suriname, French Guiana, and northern Brazil. It has a black plumage similar to rufus but with a narrower white line.
It also has a large white wing-spot and rufous flanks and undertail coverts.
Related Species
The White-lined Tanager is part of a diverse group of birds belonging to the subfamily Tachyphoninae, which includes other tanagers and finches with similar morphological and behavioral traits. Some of the related species to the White-lined Tanager are:
Tachyphonus coronatus (Ruby-crowned Tanager): A widespread South American species that has a black plumage with a red crown and a yellow belly.
Tachyphonus surinamus (Surinam Tanager): A South American species that has a black plumage with a buffy shoulder patch and a white belly. Chlorothraupis carmioli (Carmiol’s Tanager): A Central American species that has a black plumage with a yellow-orange rump and a white belly.
Ramphocelus icteronotus (Yellow-rumped Tanager): A South American species that has a black plumage with a yellow rump and tail coverts and a white belly.
Historical Changes to Distribution
The distribution of the White-lined Tanager has undergone some significant changes over time, reflecting the influences of biogeography, climate, and human activities. Fossil evidence suggests that relatives of the White-lined Tanager existed in South America at least since the late Miocene, around 6 million years ago, and that the diversity and distribution of the group have increased and expanded during the Pliocene and Pleistocene, around 3-1 million years ago.
The White-lined Tanager is considered a relatively recent colonizer of the Caribbean islands, with Trinidad and Tobago being the only natural range of the species. In modern times, the distribution of the White-lined Tanager has been affected by various factors, such as deforestation, fragmentation, and climate change.
The species is considered common in most parts of its range, but its numbers may be declining in some areas due to habitat loss and degradation. For example, in the Atlantic Forest of Brazil, the White-lined Tanager occurs only in isolated forest remnants, many of which are under threat from logging, agriculture, and urbanization.
On the other hand, the White-lined Tanager has expanded its distribution or increased in abundance in some places where forests have been regenerating or protected. For instance, in Costa Rica, the White-lined Tanager has been recorded in secondary forests and corridors connecting primary forest fragments, suggesting its adaptability to modified landscapes.
In conclusion, the White-lined Tanager is a fascinating bird species with a rich taxonomic, geographic, and ecological history. Its variation, subspecies, and related species provide valuable insights into the evolution and diversification of South American birds.
The changes in its distribution over time also remind us of the ongoing challenges and opportunities for conservation and management of tropical forests and their biodiversity.
Habitat
The White-lined Tanager is a neotropical bird species that inhabits various forest types, from lowland rainforests to montane cloud forests, as well as semi-open areas adjacent to forests, such as forest edges, clearings, and second-growth habitats. The species occurs from sea level to about 1600 m (5250 ft) of elevation, depending on the latitude and topography.
In general, the White-lined Tanager prefers humid and sheltered habitats with abundant food resources, such as fruiting trees, flowers, insects, and small arthropods. The availability of suitable habitats and food sources is critical for the survival and reproduction of the species, as well as for the maintenance of the forest ecosystem.
Lowland tropical rainforests are the primary habitat of the White-lined Tanager, where it occurs in the sub-canopy and canopy layers, mainly between 5-20 m (16-66 ft) from the ground. The species may form mixed-species flocks with other birds, such as flycatchers, woodcreepers, and tanagers, during non-breeding periods, especially in areas with high diversity and abundance of insects and fruits.
The White-lined Tanager may also visit forest gaps and edges, where it can find a variety of resources and niches, such as flowering plants, epiphytic mosses and ferns, and fallen fruits. However, the species is not well adapted to open or disturbed habitats, where it may be exposed to predators, parasitism, and harsh weather conditions.
Montane cloud forests are another important habitat of the White-lined Tanager, especially in the Andean region of South America. Cloud forests occur at elevations above 1000 m (3300 ft) and are characterized by persistent fog and mist, high humidity, and frequent rainfall, creating a unique micro-climate and vegetation structure.
The White-lined Tanager occurs in the upper understory and canopy layers of cloud forests, where it feeds on a variety of fruits, flowers, and insects. The species may also participate in mixed-species flocks with other mountain birds, such as tapaculos, antpittas, and warblers, which form intricate social networks and vocalizations in the dense and complex forest environment.
Movements and Migration
The White-lined Tanager is generally considered a non-migratory species, as it does not undertake long-distance movements or seasonal changes in range. However, the species may exhibit some movements or local movements within its range, depending on the availability of food, water, and shelter.
For example, during the breeding season, the species may undergo altitudinal movements or changes in habitat use, shifting from montane forests to foothill or lowland forests, where food resources may be more abundant or predictable. Conversely, during the non-breeding or winter season, the species may form mixed-species flocks and travel within its range, seeking areas with a high diversity and abundance of food resources and avoiding areas with low productivity, such as burned or degraded forests.
In some parts of its range, the White-lined Tanager may also experience some movements or changes in distribution due to anthropogenic activities, such as deforestation, logging, or urbanization. These activities may fragment or destroy the natural habitats of the species, forcing it to relocate or adapt to new conditions.
For example, in Brazil, the White-lined Tanager has been observed to expand its distribution or abundance in areas with low-intensity agriculture or agroforestry, where the species can find alternative fruits and seeds. In contrast, in areas with high-intensity agriculture or urbanization, the species may disappear or decline rapidly, as it may have high sensitivity to habitat disturbance and predation by domestic cats or dogs.
The movements and migration of the White-lined Tanager are still poorly understood, and further studies are needed to elucidate the details and mechanisms of these phenomena. Some of the methods that may be used to investigate the movements and migration of the species include satellite tracking, stable isotope analysis, genetic sequencing, and citizen science.
The information derived from these studies may help to improve our understanding of the ecology, behavior, and conservation of the White-lined Tanager and its natural habitats.
Diet and Foraging
Feeding
The White-lined Tanager is primarily a frugivorous bird, meaning it primarily feeds on fruits and related plant materials, such as flowers and nectar. However, it may occasionally consume insects and other small arthropods, especially during the breeding season or when fruits are scarce.
The species may also participate in mixed-species flocks, which can increase the diversity and abundance of food resources available to the birds. Foraging for food is mainly done through active seeking and handling of fruits, rather than gleaning or probing for insects.
The White-lined Tanager is a skilled and dexterous feeder, capable of manipulating small and large fruits with its bill and tongue. The species may use various techniques to obtain fruits, such as pecking, biting, tearing, or swallowing whole.
The size and type of fruit consumed by the White-lined Tanager may vary depending on the availability and quality of the food resource. Some of the preferred fruit species of the species include Ficus, Cecropia, Psidium, and Trema, which are rich in sugars, vitamins, and minerals.
The White-lined Tanager may also visit flowers or sap wells to obtain nectar, which can supplement its diet with additional energy and nutrients.
Diet
The diet of the White-lined Tanager is primarily composed of fruits, which provide the bulk of the energy and nutrients needed for the bird’s survival and reproduction. Fruits are rich in carbohydrates, lipids, proteins, and minerals, essential for growth, maintenance, and reproduction.
The White-lined Tanager may consume a wide variety of fruits, from small berries to large fruits, depending on their availability and accessibility. The fruiting phenology of different plant species may also influence the diet composition of the species, leading to changes in the timing and quality of food resources.
The White-lined Tanager may also consume insects, especially during the breeding season, when the demand for protein and fat is high. The species may prey on small arthropods, such as beetles, spiders, and caterpillars, using its bill to grasp and kill the prey.
However, the proportion of insects in the diet of the species is usually low, compared to other insectivorous birds, due to