Why does a goose have more feathers suitable for making pillows than a fowl? In what country did the domestic fowl originate? (Encyclopedia.) Why does a cock crow for day? (Consider animal life in jungle.) =Activities of a Bird.=--Observe a bird _eating_. Does it seem to chew or break its food before swallowing? Does it have to lift its head in order to swallow food? To swallow drink? Why is there a difference? After feeding the bird, can you feel the food in the crop, or enlargement of the gullet at the base of the neck? (Fig. 304.) Feel and look for any movements in _breathing_. Can you find how often it breathes per minute? Place hand under the bird’s wing. What do you think of its _temperature_; or better, what temperature is shown by a thermometer held under its wing? Do you see any connection between the breathing rate and the temperature? Test (as with the crayfish) whether a bird can _see_ behind its head? Notice the movements of the nictitating membrane. Does it appear to be transparent? Watch a bird _fly_ around a closed room and review the questions on Control of Flight. _Bend_ a bird’s leg and see if it has any effect upon its toes. Notice a bird (especially a large fowl) walk to see if it bends its toes as the foot is lifted. Pull the rear tendon in a foot cut from a fowl for the kitchen. Does the bird have to use muscular exertion to _grasp_ a stick upon which it sits? Why, or why not? When is this bending of the toes by bending the legs of special advantage to a hawk? To a duck? A wading bird? Why is a fowl safe from a hawk if it stands close to a tree? [Illustration: FIG. 303.--HEAD OF WOODPECKER. _c_, tongue; _a_, _b_, _d_, hyoid bone; _e_, _q_, windpipe; _f_, salivary gland.] Do you see any signs of teeth in the bird’s jaws? Why are duck’s “teeth” (so called by children) not teeth? Can the tongue of a bird be pulled forward? (Fig. 303.) What is its shape? If there is opportunity, dissect and study the slender, bony (hyoid) apparatus to which the base of the tongue is attached (Fig. 303), the opening of the windpipe, or trachea, the slit-like opening of windpipe which is so narrow as to prevent food falling into the windpipe. [Illustration: FIG. 304.--ANATOMY OF DOVE × ¹⁄₂. _bk_, keel of breastbone; _G_, _g_, brain; _lr_, windpipe; _lu_, lung; _h_, heart; _sr_, gullet; _k_, crop; _dr_, glandular stomach; _mm_, gizzard; _d_, intestine; _n_, kidney; _hl_, ureter; _eil_, openings of ureter and egg duct into cloaca, _kl_.] [Illustration: FIG. 305.--FOOD TUBE OF BIRD. _P_, pancreas; _C_, cæca. =Question:= Identify each part by means of Fig. 304.]