There is nothing remarkable in the nest of the Chloropsis; it is a shallow cup, devoid of lining, placed fairly high up in a tree. July and August are the months in which to look for nests. Two eggs usually form the complete clutch. It would thus seem that green bulbuls have not a great many enemies to fear. Nevertheless they fuss as much over their eggs as some elderly ladies of my acquaintance do over their baggage when travelling. Birds and people who worry themselves unduly over their belongings seem to lose these more often than do those folk who behave more philosophically. Take the case of the common bulbuls. These certainly lose more broods than they succeed in rearing, yet the ado they make when a harmless creature approaches their nest puts one forcibly in mind of the behaviour of the captain of a Russian gunboat when an innocent vessel happens to enter the zone of sea in the centre of which the Czar’s yacht floats.
XXII
CORMORANTS
Cormorants, like Englishmen, have spread themselves all over the earth. Save for a few out-of-the-way islands, there is no country in the world that cannot boast of at least one species of cormorant. Cormorants, then, are an exceedingly successful and flourishing family. It must be very annoying for those worthy professors and museum naturalists who are always lecturing to us about the all-importance of protective colouration that the most flourishing families of birds—the crows and the cormorants—are as conspicuous as it is possible for a thing in feathers to be.
Mr. Seton Thompson well says that every animal has some strong point, or it could not exist; and some weak point, or the other animals could not exist. Cormorants have several strong points, and that is why they flourish like the green bay tree, notwithstanding their conspicuous plumage. They are as hardy as the Scotchman, as voracious as the ostrich, as tenacious of life as a cat, to say nothing of being piscatorial experts, powerful fliers, and champion divers.
The cormorant family furnishes a very good example of the manner in which new species arise quite independently of natural selection. Notwithstanding their world-wide distribution, all cormorants belong to one genus, which is divided up into thirty-seven species. Of these no fewer than fifteen occur in New Zealand—a country not characterised by a large avifauna.
One species—the large cormorant (Phalacocorax carbo)—flourishes in almost every imaginable kind of climate and among all sorts and conditions of birds and beasts. Yet in New Zealand, in a country where the conditions of existence vary but little, cormorants have split up into fifteen species. It is therefore as clear as anything can be in nature that we must look to some cause other than natural selection for an explanation of the multiplicity of species of cormorant in New Zealand. It seems to me that the solution of this puzzle lies in the fact that the conditions of life are comparatively easy in New Zealand. Consequently a well-equipped bird like a cormorant is allowed a certain amount of latitude as to its form and colouring. In places where the struggle for existence is very severe, where organisms have their work cut out to maintain themselves, the chances are that every unfavourable variation will be wiped out by natural selection; but if the struggle is not particularly severe, or if a species has something in hand, it can afford to dispense with part of its advantage and still survive. Thus it is that in New Zealand we see a number of different species of cormorant living side by side. De Vries likens natural selection to a sieve through which all organisms are sifted, and through the meshes of which only those of a certain description are able to pass. Bateson compares it to a public examination to which every organism must submit itself. Those animals that fail to get through are killed. The standard of the examination may vary in various parts of the world.
So much for cormorants in general and the puzzle they present to evolutionists. Let us now consider for a little while our Indian cormorants. For once India is at a disadvantage as compared with New Zealand. There are but three species found in this country—the great, the lesser, and the little cormorant. The last—Phalacocorax javanicus—is the most commonly seen of them all. It is to be found in the various backwaters round about Madras, being especially abundant in the vicinity of Pulicat. At the place where the canal runs into the lake there are a number of stakes driven into the canal bed; these project above the level of the water, and on every one of them a little cormorant is to be seen. Cormorants in such a position always put me in mind of the pillar saints of ancient times. Although very active in the water, cormorants become statuesque in their stillness when they leave it.
The lesser cormorant (Phalacocorax fuscicollis) breeds in nests in the trees on the islets which stud the Redhills Tank near Madras, also on the tank at Vaden Tangal, near Chingleput. The third species of cormorant found in India is the great cormorant (Phalacocorax carbo). This is the one which is world-wide in its distribution. It is a large bird, being over 2 ft. 6 in. in length. It is said to be capable of swallowing at one gulp a fish fourteen inches long. It is less gregarious in its habits than the other cormorants, but it breeds and roosts in colonies. Captain H. Terry states that this species’ nests are to be met with on a tank near Bellary. The great cormorant possesses fourteen tail feathers, while all other cormorants have to put up with twelve. Why the big fellow should be the happy possessor of two extra caudal feathers is a puzzle which no one has attempted to solve.
It is not very easy to distinguish the three species of cormorant from one another. The great cormorant has a conspicuous white bar on each side of the head. This and his larger size serve to separate him from the two smaller forms. It is usually possible to distinguish the other two by the fact that the little cormorant has more white on the throat than his somewhat larger cousin. But, when all is said and done, it is not of great importance to distinguish the various species. All cormorants have almost exactly the same habits. The nests are all mere platforms of sticks. They are all expert fishermen, and seem equally at home on fresh or salt water. They can swim either on or under water and move at a considerable pace, covering nearly 150 yards in a minute. The young are said to feed themselves by inserting their heads into the gullet of the parent and pulling out the half-digested fish. Cormorants are readily tamed and are employed in China to fish for their masters, a rubber ring being inserted round the lower part of the neck in order to prevent the fish from going too far. In bygone days, fishing by means of cormorants was considered good sport, and the royal household used to have its Master of the Cormorants.
Cormorants’ eggs are of a very pale green colour, and their nests smell of bad fish, for the owners care nothing about sanitation. Young cormorants are not nearly so black as their parents, and do not attain adult plumage till they are four years old.