Sociable Weaver (Philetairus socius) Fact Sheet: Behavior & Ecology

Diurnal

• Active during daylight

Daily activity patterns (from Maclean 1967 unless otherwise noted)

• Activity not organized or scheduled
• Weavers leave and enter the colonial nest throughout the day
• Onset of activity typically near dawn
• Prior to dawn, individuals may begin calling from within nest chambers
• Near sunrise, individuals emerge from the nest and become active
• May perch on top of the nest mass and chirp
• Time dependent on weather conditions
• Fly to and from feeding grounds throughout the day
• Often decrease activity near mid-day on hot summer days
• May rest within the nest or in the shade of bushes near the feeding area
• Near sunset, individuals return to the nest to roost for the night

Remain near nests

• Typically found within 1.5 km (0.9 mi) from colony's nest (Maclean 1973e)

Nest as center of activity (from Maclean 1967 unless otherwise noted)

• Living area for all members of the colony
• Not solely a structure for reproduction
• Provides refuge
• Protects against the elements
• Rain shelter
• Shade from the sun
• Affords cover from many predators, though not climbing snakes
• Serves as a roost site for sleeping at night
• Multiple adults may sleep within the same nest cavity, though pairs roost together during the reproductive season

Highly social birds (from Maclean 1967 unless otherwise noted)

• Cooperate to build nests and care for young
• Large, apartment-like nests house colony members (from Maclean 1967; Maclean 1973b)
• Read nest architecture description under Reproduction & Development
• Older siblings and fellow colony members may assist parents in feeding chicks (Covas et al. 2006; Craig 2004; Maclean 1967)
• Form colonies
• 1 or more large nest masses built within a single tree
• Member birds feed together in flocks
• Colony size range
• Highly variable
• Limited by the structure (tree or group of trees) on which nest masses are constructed
• Colonies tend to grow until the structure no longer supports additional nests
• 2-500 birds (Maclean 1973a)

Social organization

• Birds maintain affiliation with a single nest mass  (from Altwegg et al. 2014; Covas et al. 2002; Maclean 1967)
• Affiliation maintained even when multiple nests are located within a single tree
• Inter-nest movements are extremely rare; inter-nest movements are c. 7%
• Interloping birds are often chased off
• Social hierarchy apparent within a colony (from Rat et al. 2014)
• Recent research suggests dominance is positively associated with bib size (dark patch of feathers on the throat)
• Members of the same sex assess dominance within their sex by the size of throat bibs
• Results contradict earlier suggestions that birds within a colony lack social ranking (Maclean 1967; Rat et al. 2014)

Aggression (from Maclean 1967)

• Antagonistic toward non-nest members (weavers inhabiting other nest masses)
• Threaten one another
• Aggressor advances on opponent with bill open and tail fanned
• Often preceded by a threat call vocalization (see description below)
• Peck at one another
• Direct blows toward the head, occasionally at other body regions
• May grasp and hold one another’s feathers
• At times, fights end with the participants falling to the ground

Affiliative behaviors (Maclean 1967)

• Social preening
• Allo-preening, one bird cleans the feathers of another
• Seldom observed

Sunbath (from Maclean 1967; Maclean 1973e)

• Fluff out feathers while perched atop the nest mass or on the ground
• Most often in the morning shortly after sunrise
• Wings droop to expose the back and sides to the sun’s rays

Clean feathers (from Maclean 1967; Maclean 1973e)

• Preen
• Run bill through feathers to straighten and clean
• Often observed in early morning or late afternoon while at rest on the nest mass
• Scratch
• Rub feet on the wings and head
• Commonly accompanies preening

Clean bill (from Maclean 1967; Maclean 1973e)

• Scrape bill quickly on alternate sides of a branch
• Typically after feeding on moist or “messy” foods

Bath (from Maclean 1967; Maclean 1973e)

• Rarely  wash in water

Stretch (from Maclean 1967; Maclean 1973e)

• Spread both wings over the back
• Head lowered and neck extended forward
• Yawn to stretch the jaw

Vocalization (from Maclean 1967; Maclean 1973b unless otherwise noted)

• Seldom quiet, unless asleep
• Some common calls
• Chirp
• Given singly or in short phrases of 2-3 syllables
• Pleasant, staccato, somewhat metallic notes
• Chatter
• Series of notes; a low pitched chirp followed by a series of higher pitched, falling notes
• Call ends at nearly the same pitch as the initial note
• Phrases follow one another in rapid succession
• Producing a musical or tinkling sound
• Entry call
• Uttered by a bird as it flies from a perch into the nest chamber entrance
• Series of notes; c. 4 run up the scale, a final note drops to nearly match the pitch of the first
• Inverse of the chatter call
• Phrases follow one another in rapid succession
• Threat call
• Accompanied by actual or incipient attack
• Caller advances towards another bird, bill open and tail fanned
• Extended series of notes
• A rising and falling call; several rising notes followed by falling notes
• Terminal note nearly matches the pitch of the first
• Greeting call
• Produced by birds inside a nest chamber, directed toward another entering the nest
• Sustained chirp accompanied by a falling series of notes
• Begging call
• Given by chicks begging for food
• Accompanied by typical submissive posture; a crouched perch with drooped, quivering wings
• Drawn out set of similarly pitched notes; rather raspy

Terrestrial movements (from Maclean 1967)

• Hop
• Most frequent form of movement along the ground
• Feet held together; coming apart (one foot slightly in front of the other) during rapid progression
• Walk
• Short shuffling of the feet, typically only for one or two steps

Aerial movements (from Maclean 1967)

• Agile
• Highly maneuverable when in flight from a perch to enter a nest chamber
• Capable of ascending vertically, body held horizontally
• Hover for short periods; 1-2 seconds
• Short distance flight (<90 m or 295 ft)
• Fast and straight
• Wings beat rapidly
• Long distance flight
• Alternating pattern of wing beats
• Bursts of rapid beats interrupted by a dip in the flight path as the wings are closed

Predators (from Maclean 1967 unless otherwise noted)

• Nest predators
• Climbing snakes
• Cape Cobra (Naja nivea) and Boomslang (Dispholidus typus) (Maclean 1967; Spottiswoode 2007)
• Ratel/honey badger (Mellivora capensis)
• Pygmy Falcon (Micronisus gaber) (Covas et al. 2004a)
• Aerial and canopy predators
• Chanting (Melierax musicus) and Gabar (Micronisus gabar) goshawks
• Likely predators
•  Falco spp (Rock and Greater kestrels, Red-necked and Lanner falcons)
• Terrestrial predators
• Yellow mongoose (Cynoctis penicillata)
• Possible predators
• Caracal (Felis caracal), Cape wild cat (F. lybica), and red mongoose (Myonax ratlamuchi)

Symbiotic relationships (from Maclean 1967 unless otherwise noted)

• Nests provide structure for animals
• Other birds may settle into or onto a weaver nest mass to roost or to reproduce
• Tolerated intruders; weavers react with minimal distress (threat calls) when intruder is visible, though they do not abandon their nests
• Barn Owl (Tyto alba) and Verreaux’s Eagle-owl (Bubo lacteus)
• Pigmy Falcon (Polihierax semitorquatus)
• Shrike-like bird that does not build its own nest (Covas et al. 2004a)
• Distribution in southern Africa reflects is obligate dependence on sociable weavers (Covas et al. 2004a)
• Red-headed Finch (Amadina erythrocephala)
• Egyptian Goose (Alopochen aegyptiacus)
• Rosy-faced Lovebird (Agapornis roseicollis)
• Yellow-billed Hornbill (Tockus leucomelas)
• Lilac-breasted Roller (Coracias caudatus)
• Grey-headed Sparrow (Passer diffusus)
• Unwelcome intruders; weavers react with extreme distress and chase the intruder
• Acacia Pied Barbet (Tricholaema leucomelas)
• Opportunistic users of abandoned/deserted nests
• Familiar Chat (Cercomela familiaris)
• Numerous invertebrates inhabit nests (Maclean 1973d)
• Social wasp (Belonogaster lateritia) (Bologna et al. 2007)
• Possible mutualism; needs to be tested
• Hypotheses: birds benefit from defensive behavior of wasps toward predators while wasps benefit from increases in localized prey (flies), which may be attracted to bird feces
• Vertebrate ‘squatters’
• Skinks (Mabuya striata) and geckos (Pachydactylus bibronii) may take up residence in nests
• Possibly to feed on invertebrates
• Parasites
• Few infect adults or chicks
• None appear to adversely affect health of adults

Birds are often seen fluffing their feathers and bathing in the sun early and late in the day.

Image credit: © CraftOlogy from Flickr. Some rights reserved.

Altwegg et al. (2014)
Bologna et al. (2007)
Covas et al. (2002)
Covas et al. (2004a)
Covas et al. (2006)
Craig (2004)
Maclean (1967)
Maclean (1973a,b,d,e)
Rat et al. (2014)
Spottiswoode (2007)