During the breeding season, which extends through spring and summer, Thick-billed Weavers can be found near and in marshes and other wetlands with rank grass and reedbeds, but they roam more widely at other times and are then found from forest edges to suburban parks and gardens. They use their strong bills (ask anyone who’s ever handled a Thick-billed Weaver) to good effect feeding on fruit, pips and seeds. They’re one of the largest species of weaver in South Africa, measuring 18cm in length and weighing up to 50g.
The males alone construct the colony of characteristic dome-shaped nests anchored to two or more reeds or thick-stemmed, tall grasses, while the female, if she accepts the nest, will line the inside with soft materials. Males attempt to attract and mate with as many females as possible. The female lays a clutch of 2-4 eggs which she incubates by herself over a two week period. She’s also the sole caretaker to the chicks, which leave the nest about 3 weeks after hatching.
The Thick-billed Weaver has a very patchy distribution over sub-Saharan Africa and the IUCN considers it to be of least concern, siting a common and apparently stable population. In South Africa they’re found in the wetter eastern and northern provinces, and absent from most of the Free State and the Northern and Western Cape. They’ve actually expanded their distribution considerably in recent years due to the availability of suitably vegetated artificial wetlands, like sewerage treatment installations, being constructed.