Ploceidae Weavers and Allies
Version: 1.0 — Published March 4, 2020
Introduction
Weavers are famous for the intricacy of the knots they make with green grass, resulting, once dried, in remarkably robust and coherent structures. Beyond the nests, themselves, though, this is a fascinating group, with some of the most diverse social and mating systems of any passerine groups. Coloniality is common in these birds, but the most impressive colonial passerines are surely the red-billed queleas, which move across the seasonally unpredictable landscape of southern Africa in search of sufficient germinating grasses to fuel a breeding attempt. They may descend on the woods and fields, making overnight a colony of 30 million nests, and going through their entire breeding cycle in as little as 40 days before moving on.
Habitat
The weavers live in a wide variety of open or semi-open habitats, including marshes, open forest, scrubland, grassland, and savanna.
Diet and Foraging
Ploceid diets are varied: many open-country species feed predominantly on seeds, with a good quantity of insects taken as well, and many other species feed mostly on insects and other arthropods. They also take nectar at times, fruit, pollen, and even the eggs of other birds and other small vertebrates. They forage on insects primarily by gleaning, but also flycatch and probe nuthatch-like in the bark fissures of tree trunks.
Breeding
Breeding strategies among the weavers and their allies vary from monogamous to polygynous, and from highly colonial to solitary. Some species in the genus Malimbus have cooperative nest construction, and in others such as the social weavers, young from previous breeding attempts help feed the chicks of later nests. In polygynous species, males often construct nests or display in territories to attract females. The nests of weavers, usually constructed of grass, reeds, or sticks, are famous for their intricate woven construction. Many different methods of nest construction have been documented, and, indeed, the sparrowweavers and buffalo-weavers merely push stiff stems together into large amalgamated nest structures rather than weave coherent individual nests. Nests are often completely enclosed structures, with an entrance from either the bottom or side. Depending on the species, nest placement ranges from high in a tree, often on the delicate long tips of branches, to low in scrubby vegetation. In monogamous species, nests are often constructed by both male and female. Female weavers typically lay 2 to 6 eggs, with 2 being the normal clutch for most species. In polygynous species, females alone incubate eggs and males only occasionally help in feeding the chicks. In monogamous species, both male and female incubate eggs and feed chicks. Incubation takes 10 to 14 days, with 13 to 14 days most common. Nestlings leave the nest as early as 11 days post-hatch, but most take two to three weeks to fledge. Post-fledging care can last at least three weeks.
Conservation Status
Habitat loss is the primary threat facing ploceids, 18 species of which (16%) are of conservation concern (6 NT, 5 VU, 7 EN). The endangered Mauritius Fody Foudia rubra is limited to a single island in the Indian Ocean, where introduced rats and monkeys, along with conversion of native forest, threaten the few hundred remaining birds. The rest of the endangered weavers (Clarke’s Weaver Ploceus golandi, Usambara P. nicolli, Golden-naped P. aureonucha, and Bates’s Weavers P. batesi) and malimbes (Ibadan Malimbe Malimbus ibadanensis and Gola Malimbe M. ballmanni) all live in tiny forest fragments scattered across tropical Africa, all of which are threatened by conversion of forests to agricultural use.
Systematics History
Ploceidae is part of the large passeroid radiation of the oscine passerines. Within Passeroidea, though, its position has been difficult to determine, as few studies have tackled its relationship head-on, but rather include the weavers with many other passeroids as outgroups for other focused analyses. Thus, a large study, with better taxon-sampling outside the passeroids, found Ploceidae sister to a clade made up of Motacillidae plus Passeridae (Johansson et al. 2008b), but studies with finer taxonomic resolution within the passeroids found Ploceidae sister to Estrildidae (Sefc et al. 2003) or Estrildidae plus Viduidae (Sorenson et al. 2004, Treplin et al. 2008, Fjeldså et al. 2010). Ploceidae plus Estrildidae and Viduidae is likely sister to the New World nine-primaried oscine radiation plus Fringillidae, Passeridae, and Motacillidae (Treplin et al. 2008, Fjeldså et al. 2010).
Conservation Status
Least Concern |
80.5%
|
---|---|
Near Threatened |
8.1%
|
Vulnerable |
3.3%
|
Endangered |
5.7%
|
Critically Endangered |
0%
|
Extinct in the Wild |
0%
|
Extinct |
0.81%
|
Not Evaluated |
0%
|
Data Deficient |
0%
|
Unknown |
1.6%
|
Data provided by IUCN (2023) Red List. More information