Ontario Teachers' Manuals: Nature Study Part 24

A valuable exercise in bird study, suitable for the pupils of Form II, is the study of a pair of birds and the history of their home through the entire season.

A record, with dates, should be kept, and the following topics are suggested for observation:

Where the nest is located, protection of the nest, part of building done by each bird; eggs, number, colour, size, time required for hatching; young birds, number, description, how fed and upon what foods, time required before ready to leave the nest; history for a time after leaving the nest.

Birds suitable for study by the pupils of Form II are the crow, flicker, downy woodp.e.c.k.e.r, blue-bird, chipping-sparrow, phoebe, wren.

Correlate with art, by requiring drawings and models of the nest and its surroundings, and with language, by having pupils write the history of the nest and family.

THE TOAD

FIELD EXERCISES

Direct the pupils to watch for toads under the street lamps and on the lawns in the evenings, and to observe what they are doing.

Find out, by turning over boards, logs of wood, stones, and old stumps, where toads spend the daytime.

If there is a sandy beach near by, an interesting nature lesson is to trace a toad to its daytime retreat under a log or stone. Its wanderings and adventures during the night can be traced from the record that its trail makes in the sand.

Are toads that live in light-coloured sand of the same colour as those that live in black clay? Of what value to the toad are these differences in colour?

The pupils are thus led to see that although the toad is not a handsome animal, yet its rough, dark skin is of great value to it for concealment among the lumps of soil with which it harmonizes.

Can a dog be induced to seize a toad? Will he seize it as readily a second time as he did the first? The secretion from the glands of the toad have a biting, acid effect on the dog's mouth. This secretion will not injure a person's hands unless the skin is broken, and even then it does not "cause warts".

How many toads can you find on your lawn in one evening? How many in the vegetable garden? How many in the flower beds?

Place a toad on loose soil among some weeds and observe how it proceeds to get out of sight.

Is it true that a toad is attracted by music? Give reasons for your answer.

CLa.s.s-ROOM LESSON

Secure a few living toads and keep them in a box covered with a pane of gla.s.s. Be sure to put moist soil and damp moss in the bottom of the box in which toads, frogs, newts, or snakes are kept. This enables these animals to live in comfort, and they soon become sufficiently accustomed to their surroundings to act in a normal way.

~Observation.~--By flicking in front of a toad a small feather or a bit of meat attached to a thread, the darting out of the tongue for catching prey on its adhesive surface may be observed.

The children, by bringing slugs, caterpillars, grubs, and various insects for the toads, may learn what composes the food of the animal.

It is to be observed that the toad does not snap at an object until it moves.

DETAILED STUDY

~Observation.~--General shape; division into head, trunk, and limbs; size of head and mouth; position and structure of eyes and ears; difference in the size of the fore and hind limbs, and explanation of this difference by references to the use of the limbs; the hind foot, uses of the web; the glands on the surface of the body and their uses for protection.

Why is a large mouth useful? How are the ears fitted for life in water?

In conclusion, the teacher should make sure that the pupils appreciate the usefulness of the toad and also the beauty represented in its adaptations to its conditions of life. In these particulars the toad is a good ill.u.s.tration of the adage "Handsome is that handsome does".

LIFE HISTORY OF THE TOAD

In early spring look for the toads on the surface of the water in ponds.

The music of the toads at this time of year has been described by one naturalist as "one of the sweetest sounds of nature".

The eggs may be found in these ponds at this time. They are attached to long strings of jelly which entwine among gra.s.ses and other objects in the ponds. (Frogs' eggs are in ma.s.ses of jelly, not in strings.) Place some of the eggs in a jar of water and set the jar in the window of the school-room. A great ma.s.s of eggs is too much to put in a jar, a few dozen eggs in a pint of water will be more likely to develop. The water in the jar should be changed twice a week.

~Observations.~--The light and dark areas of the eggs, the dark area gradually increasing in size; the increase in the length of the egg; the gradual change of the dark area into the general shape of a tadpole with head and tail, the first appearance of the gills, the separation from the jelly, the movement by means of the tail, the disappearance of the gills, the growth of the hind legs and, later, of the forelegs, and the disappearance of the tail.

~Questions and Observations.~--What is the use of the dark colour of the area from which the tadpole is formed?

Explain the uses of the strings of jelly.

Describe how the tadpole swims.

Upon what does the young tadpole feed?

What is the advantage of external gills at this stage in the tadpole's life?

~Later Observations.~--The disappearance of the gills, the budding out of the hind legs and, later, the forelegs. While the legs are growing out, the tail gradually becomes smaller, at the same time the shape changes to that of the adult toad with a broad body and large mouth and eyes.

~Questions.~--What movements has the toad which the tadpole did not have?

What makes these movements possible?

Why is the mouth of the toad better suited to its manner of life than the small mouth of the tadpole would be?

Of what advantage to the tadpole was the smooth outline of its body, and why is the rougher outline of the toad's body better suited for the life of the latter?

Why would gills be unsuitable for the life of the toad?

_To the teacher._--From the dark area of the egg the tadpole develops, the dark colour absorbs the sunlight, and this causes growth. The jelly holds the eggs up so that the sun can reach them and it also keeps them from being swept away by the water. The tadpole is very small, and external gills are needed to keep it in very close contact with the water. The tail does not drop off, the substance in it is absorbed into the body of the growing toad to serve as nutriment.

Since all the changes in the development of the toad from egg to adult form take place in about one month, this comparatively rapid development makes the life history of the toad particularly suitable for observation work.

The development of the eggs of the frog or newt may be studied from preparations made in precisely the same way as those for the study of the development of the toad.

If observations on the developments of two forms are carried on at one time, interesting comparisons can be made on such points as, shape and size of the eggs, time required for development, shapes and colours of the tadpoles, activity of the tadpoles, etc.

THE EARTHWORM

~Time.~--May or June, in connection with gardening, when the working of the worms in the moist soil of the garden is quite noticeable.

Outdoor studies may be a.s.signed, as:

Observe the loose soil at the entrance to the burrows. Insert a straw in the burrow and, following it, dig downward with a garden trowel and learn the nature of the earthworm's home.

Are earthworms ever found out of their burrows during the day? If so, on what kind of days? Why do earthworms burrow deep in dry weather?