WAYS OF THE WILD.

Auckland Star, Volume LXIV, Issue 189, 12 August 1933, Page 1 (Supplement)

WAYS OF THE WILD.

THE SONG THRUSH.

NESTING IN WINTER,

(By A. T. PYCROFT.)

Miss Meadows, of Selwyn Avenue, Mission Bay, Auckland, informs me that a pair of # thrushes began building their nest on May 24 this year. Tlio first egg was laid on the 31st, and on June 4 sitting Ijegan, but no results ensued. It is not known if the hen bird forsook the nest or if anything happened to her. The nest was in taupata, Coprosma Baueri, and about 2ft from last year's earliest building site. Sitting commenced last year on June 1, when four chicks were raised to the fledgling stage and then disappeared.

On June 3, 1929, a thrush's nest was found at St. Helicr's containing four eggs. Two young were hatched on the 15tli, and on June 20 the remaining two eggs were examined and proved to bo infertile. The two young left the nest on July 1. The thrush probably liests earlier than any of the other imported birds. Blackbirds were seen building their nest on August 1. Hie sparrow is anotli ( r of the imported birds which nests ea/ly- Thrushes have been singing in Auckland since May, and it is recorded that they also commence to sing in the South Island in May. On one occasion in Christcliurcli one was heard singing on April 24. The habit 3of thrushes have not altered appreciably ill their new country. They were first introduced in Otago in 1565, and immediately established themselves. Later shipments were introduced into other parts of New Zealand. Although thrushes were liberated in Canterbury between 1867 and 1875, it was not until twenty years had lapsed that thrushes were thoroughly established there. The comparatively open country of North Canterbury was no doubt not favourable for their protection, and increase. Those liberated in Auckland in 1807 established themselves at once.

Debit and Credit. Thrushes are now to be found in abundance from one end. of Xcw Zealand to the other. They are responsible, with blackbirds, for continued and serious depredations in orchards. Before their introduction, fruit of all kinds could be grown in the open, but as they began to increase it became impossible to grow small fruits, especially, without protection. Against this must be placed the fact, states the Hon. Geo. Thomson, that they eat a great quantity of insect life, and of laud niollusca. snails especially. The latter they destroy in the orthodox manner by dropping them on to rocks, stones and hard roads, and on the sea coast they also eat periwinkles, leaving heaps of broken shells at the spots where they drop their:victims. The writer has not seen snails dropped -as described by the Hon. Mr. Thomsou. A thrush uses some hard ' .object, often stones or rocks, against which it batters the shell to pieces while holding the snail in its bill. Neither have I seen them breaking and eating periwinkles. In Xew Zealand, as in Europe, earthworms are their favourite food, but these all toelong to'introduced species.

Disseminator of Flora. The Hon. Mr. Thomson states that the effects produced on the native and introduced vegetation of New Zealand by the introductiou of thrushes and blackbirds have been very marked in at least one respect. The indigenous flora of New Zealand contains an exceptionally high proportion of plants with succulent fruit, amounting to 'approximately 16.55 per cent. In Britain about 5 per cent, and in Australia 9 per cent of the whole flora have succulent fruits. The introduction of fruit-eating birds, such as . tbrughes •anil blackbirds, which in the case of small fruits swallow them whole, and so distribute the seeds, and in the case of large ones, like plums and apric6ts, carry them off to some distance, where they soon pick off the flesh and leave the stone, has led to a considerable increase in succulent-fruited plants. A considerable proportion of the indigenous birds of New Zealand are fungivorous, and it is their prevalence which no doubt accounts for the abundance of indigenous succulent-fruited plants. The advent of the thrush and blackbird has increased this feature, though the former does not penetrate far into undisturbed forest. In great parts of New Zealand the blackberry and the sweetbriar rose are most obnoxious pests, and thrushes and blackbirds are to some extent responsible for their spread.

Effect on Germination. x This question of the-distribution of succulent-fruited plants by thrushes and similar birds is of especial interest to naturalists in New Zealand. Kerner, in his "Natural History of Plants," states that of the fruits and seeds which passed the intestines of the thrush 85 per cent germinated. In most cases the germination was retarded in comparison with seeds not so treated; but in the case of a few berries, currants and gooseberries it was hastened. The seeds of such plants as grow on richly manured soil, after passing uninjured through a bird's intestines, produced stronger seedlings than did those which were cultivated without such advantages. The time taken to pass through the alimentary cana? of a thrush was very short —half an hour in the case of the elderberry and three-quarters of an hour with seeds of the gooseberry. The majority of seeds took from one and a half to three hours to perform the journey. Small smooth seeds were retained for the longest period. We have in the thrush an ally who will assist by disseminating native succulent fruits suitable a« food for some of our native birds if we plant these trees and shrubs in our public reserves and gardens. Many exotics will also, no doubt, be spread. These should be removed so as to make the in our reserves more tvpically New Zealand. It is notable that in the Town Belt of Dunedin, a wooded area in which the vegetation is protected from all grazing animals, that there has been a marked increase in the number of individual plants of fuchsia, coprosma, me icytus, muhlenbeckia and other beny and drupe bearin" "cncra since the establishment of the° thrush in Otago. Bellbirds are plentiful in this area, and are also to be freely seen in many private gardens.