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What the sources say

Sociable WeaverPhiletairus socius

Every figure, record and mechanism on the Sociable Weaver profile was written from a source, and this is the working table behind it: 48 claims checked word for word against these sources. The left column is what the page says. The right column is the source's own words, copied, not paraphrased; a ... marks a cut and[brackets] an insertion. Open any source and check it yourself.

Profile updated

Source
01

San Diego Zoo Wildlife Alliance

Sociable Weaver. San Diego Zoo Wildlife Alliance.

The page sayswith some still standing more than a century later
The source saysSome sociable weaver nests have remained occupied for over 100 years!
The page saysone shared straw mega-nest big enough for hundreds of birds
The source saysproviding a home for 10 to 400 birds!Note: 400 rounds to 'hundreds'
The page saysTermites and other insects (about 80% of the diet), plus grass seeds
The source saysInsects make up 80 percent of their diet, and juicy harvester termites are a favorite. The rest of the sociable weaver diet is seeds from grasses.
The page sayscolonies build the world's largest bird nest
The source saysRecord holder: the sociable weaver is the builder of the largest tree nests in the world.
The page saysan insulated haystack that can weigh several tons
The source saysSome sociable weaver nests weigh several tons and can get so heavy they knock down the supporting tree.
The page saysshelter hundreds of birds
The source saysproviding a home for 10 to 400 birds!Note: 400 rounds to 'hundreds'
The page saysAt 14 centimeters tall and just 24 to 32 grams
The source saysHeight: 5.5 inches (14 centimeters) tall / Weight: .8 to 1.13 ounces (24 to 32 grams)
The page saysstretch more than 6 meters wide and close to 3 meters tall, packed with over 100 separate chambers
The source saysThe largest sociable weaver nests are over 20 feet (6 meters) wide and close to 10 feet (3 meters) tall, with more than 100 individual nesting chambers.
The page sayshome to as many as 400 birds
The source saysproviding a home for 10 to 400 birds!
The page saysThe whole thing can weigh several tons, heavy enough to bring down the tree holding it up
The source saysSome sociable weaver nests weigh several tons and can get so heavy they knock down the supporting tree.
The page saysSome of these mega-nests have stayed occupied, and constantly added to, for more than a hundred years
The source saysSome sociable weaver nests have remained occupied for over 100 years!
The page saysconstantly added to
The source saysWeaver nests need constant care because of the nature of the materials used. Weavers continually add more material to keep the nest intact.
The page saysStraw spikes guard the tunnel entrances
The source saysSharp spikes of straw protect the entrance tunnels from predators.
The page sayschicks raised with extra helpers survive better than chicks raised by their parents alone
The source saysStudies have shown that chicks raised with helpers have a better chance at surviving than those raised by the parents alone.
The page saysAbout four-fifths of a weaver's diet is insects, especially harvester termites, with grass seeds making up the rest
The source saysInsects make up 80 percent of their diet, and juicy harvester termites are a favorite. The rest of the sociable weaver diet is seeds from grasses.
The page saysmost never take a drink, getting all the moisture they need from their food
The source saysMost never take a drink, getting all the moisture they need from their food: bugs.
The page saysThe materials need constant care, so the weavers keep adding more to hold the nest together
The source saysWeaver nests need constant care because of the nature of the materials used. Weavers continually add more material to keep the nest intact.
The page sayssome nests have stayed in continuous use for more than a hundred years
The source saysSome sociable weaver nests have remained occupied for over 100 years!
The page saysSociable weavers do not migrate, and a chick may never leave the nest it hatched in
The source saysSociable weavers do not migrate; in fact, chicks may never leave the nest.
The page saysa fledgling might just move into an empty chamber nearby
The source saysFledgling chicks might just move to an empty nesting chamber nearby.
The page saysIt relies completely on the weavers' nest for its own home, often nesting side by side with the weavers
The source saysThe South African pygmy falcon relies completely on the sociable weavers' nest for its own home, often nesting side by side with the sociable weavers.
The page sayseven though it is also one of their predators
The source saysOther predators include the honey badger and pygmy falcon.
The page sayswhich also preys on the weavers
The source saysOther predators include the honey badger and pygmy falcon.
The page saysA Sparrow-Sized Bird, a Six-Meter Nest
The source saysthis sparrow-sized critterNote: six-meter half: 'The largest sociable weaver nests are over 20 feet (6 meters) wide', claimed in the body
The page saysColonies of these little brown birds
The source saysThe sociable weaver is a common little brown bird in the Kalahari region of southern Africa.
The page saysone shared, haystack-like mass with a roof of twigs and chambers of dry grass
The source saysFrom a distance, the sociable weaver nest may resemble a haystack hanging in a tree. ... Large twigs form the roof of the nest and dry grasses create the separate chambers.
The page saysthe weavers continually add material to keep it intact
The source saysWeavers continually add more material to keep the nest intact

Source
02

The IUCN Red List of Threatened Species 2024

Philetairus socius. The IUCN Red List of Threatened Species 2024: e.T22718731A263786878.

The page saysLeast Concern
The source saysIUCN Red List category: Least Concern (LC).Note: read via GBIF's copy of the Red List for IUCN taxon 22718731, because iucnredlist.org refuses scripts; per the writer brief this taxon's category could not be confirmed by script for the 2024 assessment and needs a hand check against the Red List page itself

Source
03

White, Bartholomew & Howell 1975

White, Bartholomew & Howell (1975). The Thermal Significance of the Nest of the Sociable Weaver Philetairus socius: Winter Observations. Ibis.

The page saysthe biggest nest structure made by any bird on Earth
The source saysThe Sociable Weaver of southern Africa builds the largest of all birds' nests.
The page sayseasing the impact of low outside temperatures on the birds is one clear job it does
The source saysOne readily demonstrable function served by this enormous nest is the amelioration of the impact of low environmental temperatures.

Source
04

Bartholomew, White & Howell 1976

Bartholomew, White & Howell (1976). The Thermal Significance of the Nest of the Sociable Weaver Philetairus socius: Summer Observations. Ibis.

The page saysair outside a nest swinging from 16°C to 33.5°C
The source saysAir temperatures outside the nest ranged from 16 to 33.5°C
The page saysthe temperature inside an occupied chamber moved by only seven or eight degrees, staying inside the birds' comfort zone
The source saystemperatures in occupied chambers varied over a range of only 7 or 8°C and remained well within the zone of thermal neutrality for a passerine bird of this size
The page saysThe main way a colony keeps its chambers in that comfortable band is by changing how many birds sleep in each one at night
The source saysThe principal mechanism for maintaining chambers within the zone of minimal energetic cost is changes in the number of birds in the nest chambers at night.
The page sayseven the largest nests don't stop a Cape cobra in the warm season, and one snake may eat the eggs and chicks in every chamber of a large nest
The source saysEven the largest nests, however, do not prevent predation during the warm season by snakes such as the Cape Cobra, which may consume all the eggs and young in all the chambers of a large nest.
The page saysResearchers counted up to five adults sharing a single chamber on winter nights, while in summer no more than two roosted together even though almost every chamber was occupied
The source saysIn winter we found up to five roosting adults per chamber, with some chambers left empty. In the same nest in summer we found no more than two adults per chamber but virtually all chambers were occupied.Note: 'single chamber' restates the quote's 'per chamber'

Source
05

van Dijk et al. 2014

van Dijk et al. (2014). Cooperative investment in public goods is kin directed in communal nests of social birds. Ecology Letters.

The page saysSemi-arid Acacia savannas of the Kalahari region, southern Africa
The source saysthe semi-arid Acacia savannahs of southern Africa that are associated with the Kalahari ecosystem
The page saysA Cooperative With Hundreds of Roommates
The source saysSociable weavers live in colonies varying in size from five to over 300 individualsNote: heading rounds the 5-300+ range to 'hundreds'
The page saysA single nest can shelter a colony of five to more than 300 birds
The source saysSociable weavers live in colonies varying in size from five to over 300 individuals that occupy a communal nestNote: 'single' reflects the quote's 'a communal nest' (one nest per colony)
The page saysMales who help build it tend to be more closely related to the colony members around them than males who don't build at all
The source saysnest-building males have higher local relatedness to other colony members than do non-building malesNote: 'the colony members around them' carries the quote's 'local relatedness'; 'at all' restates 'non-building'
The page saysthe sociable weaver lives in the semi-arid acacia savannas of southern Africa's Kalahari
The source saysthe semi-arid Acacia savannahs of southern Africa that are associated with the Kalahari ecosystem
The page saysA whole colony shares one nest
The source sayscommunal nests

Source
06

Paquet et al. 2013

Paquet et al. (2013). Maternal Effects in Relation to Helper Presence in the Cooperatively Breeding Sociable Weaver. PLoS ONE.

The page saysWeavers are relatively long-lived: the oldest one on record made it to 16
The source saysThese weavers are relatively long-lived (the oldest bird recorded was 16 years oldNote: corroborated by cooperative-2014's 'Sociable weavers may live up to 16 years'

Source
07

Paquet et al. 2015

Paquet et al. (2015). Antagonistic effect of helpers on breeding male and female survival in a cooperatively breeding bird. Journal of Animal Ecology.

The page saysfemales breeding with more helpers survive better themselves
The source saysfemales had a higher survival probability when breeding with more helpers
The page saysmales with more helpers actually survive worse
The source saysmale survival probability decreased with increasing number of helpers

Source
08

Rymer, Thomson & Whiting 2014

Rymer, Thomson & Whiting (2014). At home with the birds: Kalahari tree skinks associate with sociable weaver nests despite African pygmy falcon presence. Austral Ecology.

The page saysroosts and nests nowhere else
The source saysa potential predator, the pygmy falcon (Polihierax semitorquatus), which exclusively uses weaver nest colonies for roosting and nesting
The page saysKalahari tree skinks are more abundant in trees with a weaver nest than without one
The source saysWe tested whether skinks were more abundant in trees containing sociable weaver nests ... We found a significant positive association between the presence of weaver nests and skink abundance.
The page saystake refuge in the nest when threatened
The source saysWhen threatened with predation, skinks preferred to take refuge in nests.

Source
09

Lowney, Flower & Thomson 2020

Lowney, Flower & Thomson (2020). Kalahari skinks eavesdrop on sociable weavers to manage predation by pygmy falcons and expand their realized niche. Behavioral Ecology.

The page sayseavesdrop on the weavers' own alarm calls to know when trouble is near
The source saysPlayback of weaver alarm calls caused skinks to increase vigilance and flee, confirming that skinks eavesdrop on weavers.

How the table was made: a writer drafted the profile from these sources and logged each claim with its quote, a reviewer with nothing but this table checked every sentence said no more than its quote, and a script confirmed each quote appears word for word in the source. The method is in the site'sAbout page.