Bird O'clock

Endangered Delicacy: The Fascinating Life of the Damara Tern

As you walk along a sandy beach, scouring the shoreline for interesting finds, you may spot a small, streamlined bird gracefully skimming the surface of the water. Meet the Damara Tern, also known as Sternula balaenarum.

These delicate and agile birds are a rare and endangered species, found along the coasts of southwestern Africa.

Identification

Field Identification

The Damara Tern is a small bird, measuring only 19-23 cm in length, with a wingspan of 41-45 cm. These birds have a dark black cap on their heads and a bright yellow bill that contrasts strikingly against their white plumage.

Their wings and back are a soft grey, and they have black legs that are barely visible in flight.

Similar Species

The Damara Tern can be easily confused with several other tern species. The most similar is the Little Tern, which shares the same yellow bill and white plumage.

However, the Damara Tern has a much darker cap, making it easy to distinguish between the two. Other similar species include the Cabot’s Tern and the Antarctic Tern, but both of these have distinct differences in plumage and range, making them easy to identify.

Plumages

The Damara Tern has two distinct plumages, breeding and non-breeding. During breeding season, which occurs from August to December, the Damara Tern has a striking black cap that covers the entire head, extending down to the nape of the neck.

The rest of the plumage remains the same, with soft grey wings and back, and white underparts. During non-breeding season, the Damara Tern’s cap fades to a more mottled black and white pattern, with the white extending further down the neck and onto the chest.

The rest of the plumage remains the same, making it easy to identify these birds year-round.

Molts

The Damara Tern undergoes a complete molt once a year, usually after breeding season in December to January. During this time, the birds replace all their feathers, which helps keep their plumage in top condition for flying and foraging.

Young birds may also undergo a partial molt, replacing some of their immature feathers with adult feathers. In conclusion, the Damara Tern is a fascinating and rare bird species found along the coasts of southwestern Africa.

They are easily identified by their bold black cap and bright yellow bill, and are often mistaken for other tern species. With a distinct breeding and non-breeding plumage, and a yearly molt, the Damara Tern is a unique and adaptive bird that is an important part of the coastal ecosystem.

The Damara Tern, Sternula balaenarum, is a species of bird that is native to the southern coast of Africa. It belongs to the family Laridae, which includes gulls, terns, and skimmers.

This species is endemic to the coastal areas of Namibia and South Africa, where it is often found in small groups or pairs near the water’s edge. In this expansion, we will take an in-depth look at the systematics history of the Damara Tern, including its geographic variation, subspecies, and related species.

We will also explore the historical changes to the species’ distribution over time.

Systematics History

The Damara Tern was first described by the German botanist and ornithologist, Eduard Rppell, in 1845. However, the species’ classification and systematics history have gone through several changes over the years.

Until recently, the Damara Tern was classified as a subspecies of the Little Tern, Sternula albifrons. However, molecular phylogenetic studies carried out in the early 2000s confirmed that the Damara Tern is a distinct species, separate from the Little Tern.

Geographic Variation

Like many bird species, the Damara Tern shows geographic variation in plumage and morphology across its range. Birds from the northwest coast of South Africa have a darker crown, while birds from the southeast coast have a paler crown.

This variation in plumage may be due to genetic differences between populations or the result of environmental factors.

Subspecies

The Damara Tern has three recognized subspecies: italic textS. b.

albidinucha, S. b.

balaenarum, and S. b.

tavaresi. S.

b. albidinucha is found in Namibia and has the palest crown of the subspecies.

S. b.

balaenarum is found in South Africa and has a dark crown. S.

b. tavaresi is found on the west coast of South Africa and is intermediate in plumage between the other two subspecies.

These subspecies are distinguished primarily by differences in the color of the crown.

Related Species

The Damara Tern is closely related to several other species of terns, including the Little Tern, the Gull-billed Tern, and the Least Tern. These species are all part of the genus Sternula, which also includes the Fairy Tern and the bridled tern.

The Damara Tern is most closely related to the Little Tern, which is found in Europe and Asia.

Historical Changes to Distribution

The Damara Tern is a relatively rare bird, and its population is vulnerable due to habitat loss and human disturbance. The species has never been particularly common, but its population has likely declined in recent years due to human activities such as coastal development, oil spills, and disturbance by tourists and fishermen.

Historically, the Damara Tern was believed to have a larger range than it currently does. Early accounts suggest that the species was once found along the coasts of Angola, but there are no modern records of the species occurring there.

The range of the species has likely contracted due to habitat loss and other human activities. In conclusion, the Damara Tern is an endemic bird species found along the southern coast of Africa.

The species has a complex systematics history, with recent studies confirming that it is a distinct species from the Little Tern. The Damara Tern shows geographic variation in plumage across its range and has three recognized subspecies.

The species is closely related to several other species of terns and has likely experienced a contraction in its range due to habitat loss and other human activities. Given the species’ rarity and vulnerability, ongoing conservation efforts are necessary to ensure the survival of the Damara Tern in the wild.

The Damara Tern, Sternula balaenarum, is a small and delicate bird that is highly adapted to a specific habitat. In this expansion, we will take a closer look at the Damara Tern’s habitat, movements, and migration patterns.

We will explore how this species has adapted to its environment, and how it moves around its range.

Habitat

The Damara Tern is a coastal bird that is found primarily on sandy and rocky beaches. It tends to prefer open and sparsely vegetated habitats near the water’s edge, such as estuaries, lagoons, spits, and islands.

It is also sometimes seen in salt pans and other shallow saline habitats. In general, the Damara Tern prefers areas with fewer disturbances, such as from human activity or other wildlife.

The Damara Tern is highly dependent on its habitat, as it relies on the availability of small fish and invertebrates for food. It also requires a well-camouflaged environment in which to nest and raise its young.

Therefore, habitat loss and disturbance are significant threats to the long-term survival of the species.

Movements and Migration

The Damara Tern is a non-migratory species, meaning that it does not undertake long-distance migrations to other areas. Instead, it moves around its range in response to local environmental conditions and availability of resources.

The species is generally resident in its breeding range year-round, however individual birds may undertake small-scale seasonal movements in search of food and suitable nesting habitat. During the breeding season, the Damara Tern breeds in small colonies or pairs.

It typically nests on sandy beaches or shell-covered flats above the high water line. Its nest is a shallow scrape in the sand, lined with shells, pebbles, or other debris to blend in with the surroundings.

The Damara Tern lays two to three eggs, which are incubated by both parents for about three weeks. The young birds fledge after about 25-30 days and become independent shortly after.

During the breeding season, the Damara Tern is highly protective of its nest and young, and will dive-bomb intruders or predators that come too close. Outside of its breeding season, the Damara Tern may form loose feeding flocks, often in association with other tern species.

These flocks can be seen feeding along the shoreline or near estuaries and lagoons, where they catch small fish and invertebrates in shallow water.

Conservation

Due to habitat loss and disturbance, the Damara Tern is classified as endangered by the International Union for the

Conservation of Nature (IUCN). Its population is estimated to number only a few thousand individuals, with the majority of these found in Namibia and the remainder in South Africa.

Conservation efforts have focused on protecting the species’ habitat, particularly along the Namibian coast where it is most threatened by human disturbance and construction. Other measures include monitoring population trends and conducting research into the species’ biology and ecology to better inform conservation efforts.

In conclusion, the Damara Tern is a coastal bird that is highly adapted to specific habitats along the southern coast of Africa. It relies on sandy and rocky beaches, estuaries, and shallow water for feeding and nesting.

The species is non-migratory but may undertake small-scale movements in response to local environmental conditions. The Damara Tern is classified as endangered, primarily due to habitat loss and disturbance, and conservation efforts are essential to ensure the survival of this unique and delicate bird species.

The Damara Tern, Sternula balaenarum, is a highly specialized bird species adapted to specific coastal habitats. In this expansion, we will discuss the bird’s diet and foraging strategies, as well as its sounds and vocal behavior.

Diet and Foraging

Feeding

The Damara Tern is a highly opportunistic predator and is known to feed on a wide variety of prey depending on local conditions and availability. Its diet consists mainly of small fish and invertebrates that are found in the intertidal zone, shallow water, or at the surface of the ocean.

Common prey items include sand eels, shrimp, crabs, and small fish such as anchovies and sardines. The Damara Tern is a plunge-diver, which means that it dives into the water from a height to catch its prey.

It is well-adapted to hunting in shallow water, and it can hover over the water’s surface to quickly catch prey that comes to the surface. The bird usually hunts alone, although it may form small feeding flocks with other terns.

Diet

As an endothermic animal, the Damara Tern has a high metabolic rate and requires a high-energy diet to sustain its body temperature. It also has a high water requirement, which means that it must drink regularly to maintain its hydration levels.

The bird’s diet is therefore essential to its survival, and it must be able to adapt to changing environmental conditions to find food.

Metabolism and Temperature Regulation

The Damara Tern is a small bird with a fast metabolism, which means it is highly dependent on a constant supply of food. To maintain its body temperature, the bird must consume enough energy to produce heat and maintain a steady metabolic rate.

This can be particularly challenging in colder temperatures, as the bird must work harder to regulate its body temperature. Furthermore, the Damara Tern must also be able to regulate its temperature in hot coastal environments.

The bird has several adaptations to help it manage heat, including panting and shallow water baths to cool off. It may also adjust its foraging behavior and time of activity to avoid the hottest parts of the day.

Sounds and Vocal Behavior

Vocalization

The Damara Tern has a variety of calls and vocalizations that it uses to communicate with other birds and to mark its territory. It has a high-pitched and nasal call that can be heard across the coastal habitats where it lives.

The birds use these calls to stay in touch with each other while foraging or when there is a potential predator nearby. During the breeding season, the Damara Tern has a distinctive courtship display that involves a series of aerial maneuvers.

During this display, the male bird will fly high into the air and then fold its wings and dive towards the female while calling. This display is thought to be a way for the male to attract the female and establish his territory.

In conclusion, the Damara Tern is a highly specialized bird species adapted to specific coastal habitats. To sustain its high metabolism and body temperature, the bird must feed on a high-energy diet of small fish and invertebrates.

It is a plunge-diver and hunts alone for its prey. To regulate its body temperature, the bird has several adaptations, including panting and shallow water baths.

The Damara Tern has a variety of calls and vocalizations that it uses to communicate with other birds, including a distinctive courtship display during breeding season. The Damara Tern, Sternula balaenarum, is a fascinating and unique bird species that is adapted to a specific coastal habitat.

In this expansion, we will discuss the behavior of the Damara Tern, including its locomotion, self-maintenance, agonistic behavior, sexual behavior, breeding, and demography and populations.

Behavior

Locomotion

The Damara Tern is highly adapted to a coastal environment and is a strong flier and a skilled swimmer. It can hover over the water’s surface or plunge dive into the water to catch prey.

On land, the bird moves on a running and hopping gait, and it may also engage in short flights to escape predators or to move between feeding areas.

Self Maintenance

Like most bird species, the Damara Tern engages in regular self-maintenance activities, such as preening, bathing, and sunning. Preening is particularly important for these birds since they need to keep their plumage in good condition for flight and to maintain insulation.

Sunning is useful in colder environments, allowing the bird to warm up in the sun and increase its body temperature.

Agonistic Behavior

The Damara Tern is highly territorial during the breeding season and will defend its nest and young aggressively against any potential threats. The birds may dive-bomb intruders or predators that come too close to the nest, using their sharp beaks and claws to protect themselves and their offspring.

Sexual Behavior

During the breeding season, the Damara Tern engages in distinctive courtship displays as part of its sexual behavior. The male will fly high into the air and then fold its wings and dive towards the female while calling.

This display is thought to be a way for the male to attract the female and establish his territory.

Breeding

The breeding cycle of the Damara Tern begins in August, and the birds will typically produce one or two clutches per season. The birds usually nest in small colonies or pairs on sandy beaches or shell-covered flats near the water’s edge.

The nest is a shallow scrape in the sand, lined with shells, pebbles, or other debris to blend in with the surroundings. The female will lay two to three eggs, which are incubated by both parents for around three weeks.

The chicks hatch with a soft downy covering, and both parents will take turns feeding and brooding them. The young birds fledge after around 25-30 days and become independent shortly after.

Demography and Populations

The Damara Tern is classified as an endangered species due to habitat loss and disturbance. The population of the species is estimated to number only a few thousand individuals, with most found in Namibia and the remainder in South Africa.

The bird usually breeds in small colonies or pairs, and these groups may be distributed unevenly across its range. The survival of this fascinating bird species is dependent on concerted and continuous conservation efforts.

In conclusion, the Damara Tern is a unique and fascinating bird species adapted to a specific coastal habitat. The bird’s behavior includes skilled locomotion, self-maintenance, agonistic behavior, sexual behavior, and breeding patterns.

The survival of the species is threatened due to habitat loss and disturbance, highlighting the need for conservation efforts to be taken. The Damara Tern, Sternula balaenarum, is a rare and endangered bird species endemic to the southern coast of Africa.

Being adapted to a unique coastal habitat, the bird’s diet and foraging are precise, behaviors are distinct, reproduction cycles are strategically planned, and populations are at risk of endangerment.

Conservation efforts to preserve critical habitats for the bird will secure its population from total depletion.

Studies on the behavior of the Damara Tern- its locomotion, self-maintenance, agonistic, and sexual behavior, proved significant and informative even to non-ornithologists. With the tremendous ecological importance of preserving our biodiversity, scientific research and conservation programs would perpetuate the population of this delicate yet fascinating bird species.

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