The Nature Column.

Digger (Invercargill RSA), Issue 7, 30 April 1920, Page 4

The Nature Column.

(By "Student.")

("Student" will be pleased to receive notes on any branch of Natural History. Observations on birds, insects, flants, etc., will he equally welcome. f using a pen-name, will correspondents please enclose real name and address.) Dear Student, — In your Nature Column of April 16th, appears a very interesting communication from Mr Jrdes Tapper, regarding the survival of native birds on the Titi Islands. On this matter I would like to hear more particulars, and there is no one more able to give them than Mr Tapper. In the first place, were the impcrted birds such as sparrows, thrushes, etc., to be seen? This is in regard to the food supply which some observers have held to he the cause of the disappearances of the native species. The more hardy or Gt least the more adaptive European species being able to starve out the less energetic native ones. In this connection can you or any of your reaclers tell me if this disappearance of the native birds contemporary with the ini'ioduction of the imported ones, has been notic,ed in any other country than New Zealand. The clearing of the forest is not confined to New Zealand. Australia, North America and other parts have all beer altere by the white man's cultivation, and no doubt its effect on the fauna of other countries will have been recorded by naturalists in these parts, but at the moment I cannot recall any notes on the matter. Any information on this subject would be appreciated by myself and perhaps others. Yours etc., BUSH LOVER. T must thank "Bush Lover" for opening up this suhject of the disappearance of our native birds. A lot of information is still needed on fihe subject and comment thereon will be appreciated. I Mr Tapper is at present on a voyage to I Auckland but I hope to hear from him in F due course. Mr Guthrie Smith in his highly entertaining and valuable record, "Mutton birds and other birds," does not mention the existence of imported birds cn the islands, though I think they are to be found on Stewart Island. T do not think ihe imported birds have had so much t-o do with the rarity of the native birds as the natural enemies introduced by man. The elimination of the forest would cause a great decrease in food supply. Even so however some of the bush birds seem to hold their own very well. They even invade the town. Bush birds are in the bedges round my house, and I have seen tuis clos,e at liand. On the other hand blaekbirds and chaffirclies were noticed in the wild country at the back of Manapouri. I think however it will have diminished the chance of existence of the native birds. I have consulted a liumber of authorities but can find nothing directly hearing on the subject. Mr Guthrie Smith seems to put nesrly the whole of the blame on to the rat, but particularly tlie black species. l quote the following from the before meritioned hook : — "Rats are the worst enemies of our birds; and perhaps the bush or tree rat is even more destructive than his grey relative. The former is really the old E'.igiish black rat . On each of our mainland canips at Stewart Island, and alsu on one of our islet camps we were visited by one or two of these rats and tho damage done by them was of thc srr.allest. But although it is comparatively ha'mless to man and his property, it is tiie black rat that theatens the extinction of many of our forest birds. Even the weasels and stoats I believe do less harm, for though more blood tliirsty and wanton in their hunting, their numbers are insignificant compared with these of the rat, they get throughout the colony the credit of all the damage done, — often I think because the result of> their work is more apparent. A rat will devour his prey, v hereas a stoat or weasel will after sucking liis victim's blood, proceed on his way. Only those who see much of our hird life crui appreciate the injury done in forest lands by this black rat." Again he says, "In a part of Stewart Island w.here the wekas have been killed, l have seen the eggs of a colony of terns enlirely destroyed in a single night ; and cn rat haunted islands, also in that region, have, liour after hour, got only nests phmdered and containing broken shell." Space does not permit of furtlier quotation but I hope to return to the subject later. Mi Guthrie Smith puts in a strong plea f"r the enoouragement of tlie weka. He considers this hird one of tlie main factcrs in the preservation of the otlier natives. The small tithe of eggs taken by it being a life insurance prcmium paid PJ the rest of tlie birds.