The black-bellied seedcracker (Pyrenestes ostrinus ) is a bird species of the family Estrildidae. They live in most Central African countries and inhabit tropical rainforest. The species comprises individuals with different physical appearance which are grouped into three categories (small, large and mega bill size). Adults are mainly granivorous but diet preference varies with bill size and food availability. Black-bellied seedcrackers also exhibit very distinctive colorations with bright patches of black and red, making them easy to identify in the field. Overall, little is known about this species apart from its range, but intensive studies are currently looking at bill size variations among individuals and their effects on behaviors.
Seed predation, often referred to as granivory, is a type of plant-animal interaction in which granivores (seed predators) feed on the seeds of pla...
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TerrestrialTerrestrial animals are animals that live predominantly or entirely on land (e.g., cats, ants, snails), as compared with aquatic animals, which liv...
Oviparous animals are female animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive...
Highly social animals are those which are highly interactive with other members of their species. They live in large groups, nest in colonies, and ...
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Not a migrantAnimals that do not make seasonal movements and stay in their native home ranges all year round are called not migrants or residents.
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starts withBlack-bellied seedcrackers are small passerine birds, measuring about 15 cm and exhibiting the typical silhouette of finch family members. The species is quite common across its range and easy to identify due to its body coloration which also earned its name. Indeed, a black bright patch covers its belly and back, and stands out against the redness of its head, chest and tail. There is a slight difference in coloration between sexes: where males exhibit those intense black patches, females are colored in dull brown. Females also tend to be smaller in size. A short and conical or large-based beak, combined with big circular and centered eyes give the visual impression of a small and stocky head
Black-bellied seedcrackers inhabit tropical rainforest of Africa and nest in moist environments, near swamps, marsh, ponds, wet prairies and in moist broadleaf forest. However, they also occupy drier habitats such as dry broadleaf forest, grassland, savanna and shrubland. They are a very adaptable species. As a matter of fact, in areas contiguous to urban built-up, black-bellied seedcrackers are found in numbers in plantations (especially cacao) that offer high quality nesting branches. They are also common garden birds and benefit from feeders. Thus, the proximity to humans does not seem to negatively alter their population.
Black-bellied seedcrackers are native to Central Africa and resident birds, meaning they do not migrate over the seasons. Although little record exists for their historical home range, it is thought that it has not variated much over time. The last assessment, in 2016, showed the species occupies a wide range and is present in SE Ivory Coast, Ghana, Togo, Benin, South Sudan, Nigeria, Equatorial Guinea, Western and Southern Cameroon, Central African Republic, SW Chad, Gabon, Democratic Republic of Congo, Republic of Congo, Uganda, W Kenya, Angola, Zambia and SW Tanzania.
Diet is the second factor earning black-bellied seedcrackers their name. Adults feed on seeds that they open thanks to their hard beak. All of them mostly eat seeds from sedges, bushes from the genus Scleria. Depending on the season, the abundance of food and their bill morphology (small or large bill size), black-bellied seedcrackers broaden or specialize their diet. For example in periods of abundance, all individuals feed on various seeds, berries, insects, and few green leaves. However, in periods of scarcity, small-billed individuals specialized on soft seeds of sedge (Scleria goossensii ), whereas large-billed morphs will go for hard seeds of sedge (Scleria verrucosa ). Concerning the emerging mega morph, their larger beak allows them to open seeds of Scleria racemosa, a sedge species with an even harder shell. So all morphs coexist and really differ by their diet specificity in periods of food scarcity. Last, although the species is mostly granivorous, parents will feed juveniles with soft insects until the beak is completely formed and hardened.
Breeding season of black-bellied seedcrackers runs from March to November, peaking in April and September and coincides with rain seasons. It begins with courtship behaviors. Males show off by holding a piece of vegetation in their bill, like a long grass blade, leaf or grass panicle, and bob up and down perched in trees. Simultaneously, they sing to advertise their presence and attract females. Females are the one choosing their mate based on this display. This system in which one mate has complete choice over the other sex is called epigamic selection and is a common characteristic in the finch family. Mates stay together the entire breeding season and will build a nest a few meters from the ground using leaves. Although there is an overall synchronization among individuals for the entire breeding period and reproductive peaks, pairs differ in the timing and number of hatchings. Some will produce one hatching and others two throughout the year. Some also raise young in May, at the beginning of the breeding season, others around July and still others in October, toward the end of the season. A female lays in average 2 to 4 eggs and both parents take shifts to brood. Chicks hatch about 16 days later and parents will keep alternating to feed them. Young are altricial, meaning they are not directly independent. They stay about a month in the nest before taking off and foraging by themselves. The main cause of nest failure is due to predation (rats and snakes).
Interestingly, black-bellied seedcrackers breed regardless of bill morphs (either small-billed pairs, large-billed pairs or pairs with one individual of each morph), but no intermediate bill size arises from offspring of crosses between morphs. As a matter of fact, offspring from two small-billed parents have a small bill, large-billed pairs produce large-billed chicks, and crosses between morphs give rise to either large or small-billed individuals. So morphs are completely related to diet and not sexual selection.
Social animals are those animals that interact highly with other animals, usually of their own species (conspecifics), to the point of having a rec...