Ontario Teachers' Manuals: Nature Study Part 38

Find the nest of the downy and describe the nest and the eggs.

Do the holes made by the downy injure the trees?

Why should the downy be welcomed in our orchards?

Describe the sounds made by the birds.

_To the teacher._--Discuss the pupils' answers to the above problems in the cla.s.s lesson, using a picture of a woodp.e.c.k.e.r to ill.u.s.trate the features of the bird that adapt it for its habits. Examples: the straight, sharp beak suited for drilling; the two backward, projecting toes for perching; the spines on the tips of the tail feathers to act as a prop.

The downy woodp.e.c.k.e.r is very useful in the orchard, because it destroys great numbers of larvae of the tussock-moth and other insects. The holes made in the bark have never been found to injure the trees. The nest is made in a hollow tree, the entrance to it being almost perfectly round and about one and one-quarter inches in diameter.

The downy woodp.e.c.k.e.r has a very unmusical voice, but fortunately he is aware of this deficiency, and his only attempt at music is drumming with his beak upon a hollow limb or tree.

The hairy woodp.e.c.k.e.r, redheaded woodp.e.c.k.e.r, flicker, and yellow-bellied woodp.e.c.k.e.r (sapsucker) are other varieties which visit the orchards and are suitable for lessons similar to these on the downy woodp.e.c.k.e.r. They are all beneficial birds.

FLYCATCHERS

Members common to this cla.s.s are: king-bird; house-phoebe, wood-phoebe, or pewee; whip-poor-will; least fly-catcher; giant fly-catcher.

Direct the observations of the pupils to the following type features:

Brownish or grayish colours; fringe of long bristles around the mouth (explain their use); whistling notes, varying with the different members of the family; habit of jumping from the perch, catching an insect while on the wing, and returning to the spot from which the flight began; nests, chiefly of mud built in a protected place, as under a bridge, ledge of rock, or projecting log.

WRENS

The house wren may be studied as a type. Observe its brownish colour, faintly mottled; its small size and energetic movements, its tail turned nearly vertically upward. Observe and report on other wrens, noting any differences.

CABBAGE-b.u.t.tERFLY

Have a plant of wild mustard or a cabbage growing in a pot. In June, have the pupils, by means of the insect net, catch a number of the white b.u.t.terflies, the adults of the cabbage-worm.

Place the b.u.t.terflies in jars or bottles and observe them. Make drawings of them.

Direct the attention of the pupils to the difference between the wings of the male and those of the female. The former has only one dark spot on the front wing, while the female has two spots on this wing.

Release the males and put the females in a vivarium with the potted plant. (A pasteboard box, with a large piece cut out and the opening covered with gauze, makes a good subst.i.tute for a vivarium in this case.)

Observe the laying of the eggs. How many are placed at one spot? How are the eggs protected? The eggs may be gathered from the cabbage plants in the garden.

Observe and record the hatching of the tiny worm, its feeding, growth, forming of chrysalis, development into adult.

Frequently little yellow silken coc.o.o.ns are found in vivaria where cabbage-worms are kept; these are coc.o.o.ns of a parasite (braconid) that infests the worm.

Because of the ease with which the cabbage-b.u.t.terfly may be obtained and the rapidity of its development in the various stages, it is very suitable as a type for the study of metamorphosis.

The sulphur, or puddler (called by the latter name because of its habit of settling in groups around the edges of the water holes), is also a suitable type. The larvae in this case must be fed on clover.

THE TUSSOCK-MOTH

Begin the study of this insect in June and July by observing the larvae feeding on the foliage of the horse-chestnut and other shade trees, and direct attention to their destructiveness.

In observing the larvae, note the size, movements, legs, colour, coral red head, tufts of hair on the back, and the three long plumes.

Watch the birds among the trees to discover whether they eat the larvae.

Of what use are the tufts of hair? Do the larvae feed by biting or by sucking? Describe the damage done by the larvae.

Collect a number of these larvae and place them in the vivarium with some twigs of horse-chestnut. Observe the spinning of the coc.o.o.n and, about two weeks later, look for the emergence of the adult moths.

Observe the two kinds of insects. Describe each. Are there any differences in the coc.o.o.ns from which they emerge?

Which form of insect places the egg ma.s.s and is therefore the female?

Note the number and shape of the eggs and how they are protected.

The female moths have no wings and do not move far from the coc.o.o.ns from which they emerge, while the males have the power of flight.

As outdoor work, look for the egg ma.s.ses on trees and fences and devise means of combating the tussock-moth.

Gathering and destroying the egg ma.s.ses during the winter is found to be fairly effective in checking these insects. Since the coc.o.o.ns frequently contain parasites that prey upon the larvae, it is advisable that only the coc.o.o.ns that have egg ma.s.ses attached to them should be destroyed; the others are harmless and may contain the useful parasites.

The egg ma.s.ses may be kept over winter in a box in a cool place, and the hatching of the tiny larvae and their subsequent rapid growth observed.

POTATO BEETLE

The eggs of this beetle may be found in early summer in cl.u.s.ters on the under surfaces of the leaves of potato plants.

EGG.--Observe the size, colour, shape, position, and number in a cl.u.s.ter; appearance of head from outer end after a week.

LARVA.--Observe the colour, shape, head, legs, voracious appet.i.te, movements, rapid growth, destructiveness.

PUPA.--Observe the larvae disappear from the plants; a search underground reveals the resting stage, or pupae. After ten days, the adult beetles emerge.

ADULT.--Observe the colour, the hard sh.e.l.l covering the head; the hard outer wings and membraneous inner wings; the hard sh.e.l.l on the under surface of the body; the feelers, and legs.

Why will spraying with a poison, such as paris-green, kill these insects?

REFERENCES

Dearness: _How to Teach the Nature Study Course Stories in Agriculture, Bulletin No. 124._

FISH

The Nature Study lessons must be based upon observations of the living fish, preferably in May or June, September or October. The best place for this is on the bank of a clear stream from which it is possible to observe the fish in their natural environment. Here their life activities, their struggles, their conquests, and silent tragedies are enacted before the eyes of the observer. Many observations may be made in this way which will create a life-long interest in these reticent, yet active creatures. Since this method of study is practicable in but few cases, the study of the living fish in the aquarium is the best available subst.i.tute.

The teacher or the boys of the cla.s.s can catch a few fish of three or four inches in length and carry them in a jar of water to the aquarium.

Minnows, chub, perch, catfish, or other common forms will do.