Description:

The castle-building weaver is a species of social weavers that live in colonies. They are basal in terms of their anatomy and morphology. They are light cream with darker feathers on the wings and the tail. They have a colorful head, which comes in several different colors. These colors show the various ranks of weavers within the colony. These ranks are covered in the social behavior section of the page. They are about 13 to 15 centimeters in terms of height. They weigh about 25 to 35 grams. They live about two years in the wild.

Distribution:

The castle-building weavers live in the wooded regions of the Congo Savannah. They also require spaces with tall-growing grass species, thick shrubs, and rivers that create mud.

Diet:

These weavers mainly prey on insects, but they supplement their diet with seeds, fruit, and nectar.

Social Behavior:

These weavers have a social hierarchy in their nest, determined by their head color. The most common head color is light pink. These pink-headed individuals are designated for building and maintaining the whole nest. This pink-headed trait is dominant in the weavers, so it is the most common to show up. The less dominant trait is a bright red head. It is still dominant over other colors. The bright red head signifies the warbirds, which defend the nest from predators and threats. The red feather gene is also associated with higher rates of testosterone production. This association is due to the genes located near each other on the chromosome. Another head color is white, which is only expressed among female birds. This trait is due to the white-headed gene situated in the W chromosome in female birds. These birds are generally caretakers of chicks. They are responsible for feeding chicks, tending the insect farms, and taking care of injured birds. The last head color is the yellow-headed trait, which is the leader of the colonies. The yellow-headed trait is recessive, so it is rare in the colony. They are responsible for reinforcing the social hierarchy in the system via their head color. They are the kings and queens of the nest since they are at the top of the social hierarchy. It is important to note that, even though they are called queens and kings, they do not function as eusocial insects. They work as the colony's government, which enforces the social standing of the birds. If birds fall out of line, the queens and kings physically harass them to get them back to work.

Breeding:

Although they have distinct roles, all weavers are allowed to breed among each other and, therefore, aren't precisely eusocial. Still, they have eusocial tendencies, like communal care of the young and roles for each other. Usually, a female weaver lays one to two eggs a year. This number may seem small, but females lay their eggs together simultaneously. Given that there can be up to 250 birds in the colony, it leads to a large yield of chicks. The responsibility of the caretakers is to take care of the chicks until their head feathers form. Once they do, they go to the groups that their head feathers match to learn their role in the colony. It is also important to note that some weavers will leave the nest to join or create a new colony. This migration out of the colony prevents low genetic diversity among the birds.

Nest Building:

The nests of the castle-building weavers are probably the most notable thing about them. These giant nests can be the size of medium-sized cars, much like their ancestor sociable weaver (Philetarius socius.) Unlike their ancestors, these nests have different chambers that serve unique roles. Several entrances allow the birds to get into the nest. These entrances are tube-like and perfectly sized for the weavers to climb in comfortably. Once inside the nest, there are several different "rooms" that the weavers can go to. The largest section of the nest is the central hub, which serves several purposes. The main one is as a communication hub to deliver information and get to other centers of the nest. It also ensures a buffer zone between the entrance and the specialized areas of the nest. Smaller nests are placed along the side of the room that allows the weavers to rest during the night. One of those specialized zones is the nursery. This zone of the nest is for caring for the eggs and baby weavers until they reach adulthood. It is usually located far away from the entrances, near the top of the nest. They are also the second largest zone of the nest. The next largest zone is the termite farms. These farms are incredibly advanced for a small bird. These weavers have domesticated these insects, and the termites are genetically different from other species in the area. The birds can cultivate these termites by feeding them wood, leaves, and grasses. The worker termites are used as food and to produce chemicals (such as formic acid) that work as parasite repellents. The last room important to the colony is the food storage room. This room stores mostly seeds and other foods that the weavers gathered from outside the nest.