Avian brain and senses

1. Avian brain and senses Origin of the term bird brain

2. Intelligence and instinct Bird’s brains are small compared to most mammals and it seems that some birds are poor at learning new skills. Birds though have a large number of “programmed” behaviors (instinct) in its brain that control not only simple activities (feeding, preening, etc) but some more complex instincts such as migration

3. Central nervous system: brain & spinal cord Peripheral nervous system: cranial & spinal nerves, autonomic nerves & ganglia, & sense organs The functions of the avian nervous system: obtain (via sensory receptors) information about the internal & external environment analyze &, respond to that information store information as memory & learning coordinate outgoing motor impulses to skeletal muscles & the viscera (smooth muscle, cardiac muscle, & glands) Avian nervous system

4. Due to common ancestry Birds have relatively larger cerebral hemispheres & cerebella Birds have larger optic lobes & smaller olfactory bulbs (Husband and Shimizu 1999) Similarities of bird and reptile brains

5. Woodpeckers, corvids, and parrots have longer, larger cerebellar lobes IV, VI, VII, VIII, and IX than many other birds These areas help coordinate visual and beak-related movements, and those birds are generally very adept when it comes to using their beaks/tongues to manipulate and explore objects Birds that are excellent flyers, e.g., swifts and falcons, do not have unusually large cerebellums (suggest that well-developedmotor skills do not require an increase in cerebellum size (Sultan 2005) Some birds are ‘smarter” than others

6. Are birds intelligent? http://www.youtube.com/watch?v=eawfoMHyUHQ&feature=related Jarvis et al. 2005 Dr. Irene Pepperberg and African Grey Parrot “Alex”: more than 100 vocal labels for different objects, actions, colors and could identify certain objects by their particular material. Could count up six. Exhibited math skills that were considered advanced in animal intelligence, developing his own “zero-like” concept in addition to being able to infer the connection between written numerals, objects sets, and the vocalization of the number. He was learning to read the sounds of various letters and had a concept of phonemes, the sounds that make up words http://www.alexfoundation.org/alex_the_parrot.html

7. Humans Chimpanzees Birds Intelligence = tools use • http://www.youtube.com/watch?v=vjEnnuElMWk http://www.youtube.com/watch?v=lcvbgq2SSyc

8. So…. bird brain? • pigeons can memorize up to 725 different visual patterns, learn to categorize objects as 'human-made' vs. 'natural', & communcate using visual symbols • Scrub Jays show episodic memory: ability to recall events that take place at a specific time or place • owls have a highly sophisticated capacity for sound localization, used for nocturnal hunting, that is developed through learning (Knudson 2002) • parrots, hummingbirds, and oscine songbirds possess the rare skill of vocal learning • parrots can learn human words and use them to communicate reciprocally with humans • African grey parrots can use human words in numerical and relational concepts, abilities once thought to be unique to humans

9. Other functions of the neural system in birds • Self-recognition • Memory • Control of motor function

10. First evidence of self-recognition in birds Self-recognition in European magpies (Prior et al. 2008) (A) Attempt to reach the mark with the beak, (B) touching the mark area with the foot, (C) touching the breast region outside the marked area, and (D) touching other parts of the body

11. Males display for females Tested hypothesis that steroid sensitivity is a property of neurons in the manakin spinal cord males and females with drugs to inhibit steroidogenesis and treated with labeled testosterone Most sex steroid-accumulating cells were found in the cervical and lumbosacral enlargements Because motor neurons in these areas control muscles of the wings and legs, these cells may have multiple behavioral functions (i.e. innervate muscles controlling the elaborate dancing and wing-snapping of males) Suggesting that sex steroids may control diverse behaviors in male birds in part by acting directly on the spinal neural circuits Spinal cords and motor control in White-collared Manakins(Schultz and Slinger 1999) http://www.youtube.com/watch?v=Mf1TW5kb9S0

12. Tactile organs - touch receptors (herbst corpuscles): abundant in the bills of some birds (Anseriformes, Charadriiformes)and in the tongues of others (Piciformes) - Herbst corpuscles: the most widely distributed receptors in and found in the dermis layer of the skin, the beak, legs Touch/pressure receptors (Merkel cells): found in the featherskin of the beak and legs of birds Sense organs

13. It was thought that birds could not smell (small olfactory lobes) But most birds probably can smell and use odors in daily activities Turkey vultures, kiwis, and many Procellariformes have a well developed sense of smell Olfaction organs are on the surface epithelium of olfactory cavities Olfaction Nasal cavity of a Mallard nar = naris, co = concha (rostral,middle and caudal) , ch=- choana (opening between nasal cavity and nasopharynx (Figure from Witmer 1995).

14. Turbinate bones are found in the caudal (olfactory) concha Complex turbinate structure of a Snow Petrel's nose (large amounts of surface area are lined with olfactory epithelium), contain cells that detect odor (light green) A puffin's nose is smaller and has less olfactory epithelium Procellariiformes are often called "tubenose" seabirds because of the prominence of these structures They also have enlarged brain structures that process scents Turbinate bones

15. Kiwis are unique among birds in having the opening of their nostrils close to the tip of the maxilla In all other birds, the nostrils open externally close to the base of the bill, or internally in the roof of the mouth Sensory pits are clustered around the tips of both the maxilla and mandible, on both internal and external surfaces Such pits house clusters of mechanoreceptors (Herbst and Grandry corpuscles) protected by a soft rhamphotheca These sensory pits detect objects touching or close to the bill tips Sensory bill tips in Kiwis