Introduction

• Exploration of five arenas of daily activity for birds: talk, work, play, love, parenting
• Important to acknowledge individuality in behaviors— not all birds of a species act the same
• Focus on extreme behaviors → outliers offer perspective on what’s typical, indicate ingenious adaptations
  • Many Australian species! Aussie birds occupy more ecological niches than others → longer lived, more intelligent
  • C & S America → greatest diversity of birds, many unique behaviors
• How to measure intelligence in birds? Behavioral flexibility = how inventive the species is in its natural environment, whether it makes use of new things to solve problems
  • Novel or unusual behavior is often intelligent behavior
• How do birds have capacity for such complex cognition given small brain size?
  • More compact neurons: smaller, tightly packed, more numerous → efficient & high-speed sensory abs nervous systems
  • Concentrated in forebrain regions associated with intelligence → some parrots, corvids, have higher neuron counts there than monkeys!
  • Different approach to building powerful brains than mammals, which use larger neurons to connect distant regions
• Why so many new insights coming up now?
  • Shedding many biases that have limited research...
    • Human sensory bias on what birds can perceive
    • Geographic bias on studying mainly birds in northern regions, vs more diverse tropical species
    • Gender bias of male scientists mainly studying male birds
  • New tools/tech: sensors, cameras, DNA analysis
  • Study of wild cognition

Talk

• May be capable of compositional syntax (ex. how “watch out” is different than “out watch”), but debatable

Visual talk

• Embodied words → displays, gestures, postures
• Cosmetic coloration for sexual signalling with own secretions (Japanese crested ibis); applying mud to “paint” on feathers for camouflage, other functions (sandhill crane)
• Colorful facial plumage signalling identity (not an honest signal of fitness, as assumed initially) (queleas)

Bird song

• Originated in Australia → all songbirds descendent from there!
• Birds generally better at recognizing sound and variations in it than us, have larger perceptive range
• Bell miners → create “wall of sound” to keep other species out of their territory

Alarm calls

• Can encode lots of information— honeyeater alarm calls → 96 elements
  • Mobbing alarm calls (draws other birds toward threat) vs fleeing alarm calls (sends birds away)
  • Functionally referential signalling → can refer to specific environmental object or event (where or what kind of threat)
  • Encode what a predator is doing
• Specificity of black-capped chickadee calls: number of “dees” at the end → size and threat of predator (larger birds = less threat → fewer notes)
• Species of birds can understand each others’ alarm calls— even bird/mammals can understand each other, and species who have never encountered each other
  • Raises question of a universal language of alarm— but actually found that birds learn alarm calls from other species, like learning a new language!

Mimicry

• Deception/lying takes lots of cognitive skill— requires theory of mind, learning, planning
  • Mimicry = sign of intelligence → honest signal of fitness in mating rituals
• Lyrebird = master mimicker
• Mimicry by some species thought to be passed on through cultural transmission, not just learned from environment— birds mimicking calls of other species no longer present!

Work

Sensory perception

• Color vision: birds = tetrachromatic, see an entire additional dimension
  • UV dimension adds distinction to leafy green in rainforests that are so hard for us to distinguish
• Hearing: asymmetric ears → positional info from sound, even for smaller birds than owls
  • Echolocation in audible range (oilbirds)
• Smell: extremely sensitive in several species— turkey vultures, tube-nosed sea-birds
  • Seabirds specifically can detect tiny amts of DMS → produced when krill consume phytoplankton, but also emitted by plastic → leads to consumption of trash

Tools

• As always, initially thought to be uniquely human behavior, but more and more examples among birds
• New Caledonian crow → combines 2+ elements to make a tool, first time this was seen in any nonhuman animal
• Some species take advantage of wildfires → hunt the fleeing prey
  • Also (somewhat controversial) evidence of birds intentionally spreading fires as a hunting technique!

Cooperative hunting

• Antbirds use knowledge of army ants to “raid” their hunts and get easy access to lots of prey; work in groups to facilitate these raids
  • Requires learning, memory, pattern-recognition, planning
  • Will return to past sites of raids to check that the ants have left, communicate among each other— long-term memory, cooperation
• Mental time travel: again, thought to be a defining human ability, but now it seems several bird species can engage in it too
  • Scrub jays and other caching birds remembering where and when they buried food stores
  • Spatial and temporal memories of hummingbirds to remember the hundreds of flowers they’ve already visited, how long it’ll take for nectar to replenish

Play

• Ravens have reputation for being cruel, dark (a group is an unkindness!), but actually one of the most playful species of animals
  • Not naturally tool users, but can quickly learn
  • Show self-control, reasoning, flexible planning equal to great apes
• Kea of the parrot family = other extravagantly playful bird
  • Unlike ravens, extremely neophilic, social
  • Highly intelligent, innovative foraging, very long juvenile period— and juveniles hold higher social status than adults!
  • Very fluid social structures, not very hierarchical ← social intelligence ← social play

What is play?

• Behavior that is not fully functional
• Often exaggerated, awkward, repetitive
• Spontaneous, voluntary, intentional, pleasurable, rewarding
• Only initiated when animal is not otherwise stressed
• Three kinds of play, in increasing complexity: locomotor play (with just the body), object play, social play (requires rules, no pain, taking turns); perhaps a fourth kind of vocal play?
  • Only documented in 1% of 10,000+ bird species!
  • Rare among animal phyla and species within those overall, suggesting multiple independent evolutions

Love

Courtship displays

• Include elaborate offerings, songs, dances by males
  • Palm cockatoo → only nonhuman example of using a tool for something other than foraging
• Leks = communal spaces for male courtship display, involve done very fancy examples (dance by bird of paradise)
  • Bowerbirds = lekking birds, build ornate and decorated structures to attract mate; utilize illusions to capture attention!
• Sexual selection → traits of aesthetic beauty, rhythm, etc.?
  • Ultimately driven by experience and perspective of female bird, and her ability to judge displays is just impressive as the display itself!
  • Likely a combination of genes, honest signals, and beauty itself

Parenting

• Wide variety of parenting styles, from none to group parenting
• Variation in egg design
  • Analysis of eggs → only three factors correlated w shape (when looking across all birds): body mass, evolutionary history, flight ability)
  • Within clades, other factors become more important
• Variation in nest style, building
  • Sophisticated behavior that can involve cooperation, planning, learning (from environmental cues to choose location, from past failures)
  • Nature vs nurture? As usual, both— experience usually helps more for birds that build complicated nests
  • Brush turkeys → build literal compost heaps and maintain exact temperature as incubator for eggs; mallefowl do similarly (utilize both microbes and solar heat)

Brood parasites

• Honeyguides → cooperative relationship with human honey hunters in Africa— lead them to hive, and hunters leave then honeycomb wax, important food source
  • But also very dark parenting style— brood parasites, so lay eggs in nests of other species
  • Chicks then murder their nestmates quite brutally
• How do chicks of brood parasites learn to identify with their own species? Mother bird calls with acoustic password that primes development in auditory region of chick’s brain to learn species-specific songs
• Dynamics between brood parasites abs host species → evolutionary sense race of the host better distinguishing foreign eggs/chicks and the brood parasite better mimicking then
  • Some host species → individualized signatures on patterned eggs
  • If too hard to distinguish at egg level, some host species work at chick level to get rid of wrong species— somehow teach their own chicks special songs/passwords
    • Brood parasites chicks evolve to more closely resemble common hosts
• Host species from around the world have converged on common cuckoo alarm call → signal to mob!
• Brood parasites females require high degree of spatial awareness & intelligence to successfully reproduce, monitoring many nests at a time

Cooperative parenting

• Greater ani: not among related birds which could be explained by kin selection → what leads unrelated birds to collectively raise their young?
  • Could be for protection vs large predators like snakes, crocodiles
  • Eggs of females who lay first eggs sacrificed for nutrients of the others → great deal of cooperation and coordination, communication and judgement
  • Individuals don’t even recognize their own chicks once hatched
  • Almost act as brood parasites on their own species → still in the process of coordinating reproduction perfectly?
• White-winged chough → require four helpers to raise chicks, engage in “chick-napping” to recruit enough birds for their cause!
  • Perhaps resulting from harsh, unpredictable envt
  • But for other species, could be because good envt has ample enough resources that populations were very large, easier for young to stay around parents and learn/help than go off on their own