ALL BIRDS COME FROM EGGS

Hawera Star, Volume LIII, 19 August 1933, Page 14

ALL BIRDS COME FROM EGGS

LL birds come from eggs, but no: all eggs from birds. The eggs oj binds are generally attractive objects which cannot bo said of all eggs. The size of an egg is by no mean; always a guide to the size of the birc that produced it. The common gul lays a larger egg than the pheasant and the kiwi, a ZSTew Zealand species scarcely as big as an ordinary fowl lays an egg little inferior in size tc that of an emu—in fact, the largest egg known relatively to the btilk 0.1 the bird, as the cuckoo’s is the smallest (says a writer in the ‘ TVfanchestei Guardian”). Of birds living at the present day the ostrich lays by far the biggest egg, yet even this is dwarfed by the enormous egg of aepyornis, ar ostrieh-like bird, twelve feet high, thal once lived in Madagascar, but is now .extinct. This egg had a Capacity ol about two gallons. At the other end of the scale are the minute eggs ol humming-birds, weighing only a few grains. Often the young bird thal issues from a large egg is in a wellgrow r n condition when hatched, and able to look after itself tolerably well, whereas the tenants of smaller egg--emerge blind, pathetically helpless, and dependent for a considerable time upon parental solicitude. In the average (jase incubation is not far advanced when an egg is laid, and is checked when it becomes cold, to be resumed under the influence of warmth’ derived through one of the parents, or both in .turn, “sitting” on it, a duty that must be religiously observed for a prolonged period. Reptiles in the main reproduce through the medium of eggs, and as a rule a considerable number are laid at a time. Generally they arc of a whitish colour, not spotted as in nine out of ten species of birds, and the shell may be either membranous or chalky and brittle. Crocodiles lay from twenty to sixty oval eggs, approximately in size to those of a goose. They arc buried in the sand, and the parent is thought to assist in incubation. At any rate, the young are helped to escape from the sand when the shells break, the mother being apprised of the right moment by a peculiar noise, said to resemble crying, emitted by the infant crocodiles. Tortoises lay round eggs not unlike those of some birds of prey. Turtles

But Not All Eggs Come From Birds

>t deposit their eggs in the sand. The if green turtle digs a hole w r ith its flip8, pers and fills it with eggs to the number of 150 or more, smoothing them is over with sand, the heat-retaining prod perty of which suffices to hatch them. 11 Snakes lay numerous eggs, which f, often adhere together by means of a s, viscid substance. Sometimes the heat 1, of the sun’ alone serves to hatch them, o but development is often hastened by if, their being, placed in -decaying vegcf table matter or manure. Pythons 1- incubate them, and some reptiles arc ir viviparous—that is, the eggs are e hatched while still within the body, e Such is also the case’ witli certain aquad tic snakes, the British viviparous n iizard, and a fish known as the vivipar.tlous blenny, which produces as many v as fifty young at a birth. f The eggs of amphibians resemble d those of fishes and arc laid in water f singly, in strings, or in compact masses, v A familiar example is the spawn of the t common frog, which is found floating l- iri ponds or dikes. Each of the numerd ous eggs is surrounded by a coating of t, j albumen, which swells up in contact' s with the water to produce a compact, i jelly-like mats, partly nutritive and a partly protective, among which the e developing eriibryos (tadpoles) are cl conspicuous as -black dots that eventuI ally uncurl' and swim free of the enI tangling jelly. :1 The adult frog results, as every l schoolboy knows, through gradual t metamorphosis of the tadpole, but in i the Solomon Islands there is a land-',-frog laying eggs as large as marbles, i j from which issue fully-developed frogs, Ij a most unusual condition among amI I phibia. Another striking exception is : | the Surinam toad,- whose eggs are i ( placed by the male upon the back of i | the female, where each becomes em- • bedded in a sort of pouch from which ■ emerge later miniature but complete -frogs. , j There are even egg-laying mammals : —the spiny ant-eater aiid the duckI billed platypus of Australia. Both I creatures are unquestionably mammals, j though of somewhat lowly organisa- ! tion, and yet they lay eggs. Fishes as a class are extraordinarily ,prolifie, and their eggs are usually minute. It has been computed that the roe of a herring may contain 50,000 eggs, and that of a turbot more than