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
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