NATURE NOTES

Evening Post, Volume CVIII, Issue 102, 26 October 1929, Page 17

NATURE NOTES

FOOD OF WILD BIRDS

RESULTS OF INVESTIGATIONS

(By K. H. D.Stidolph,BJLO.TT.)

. Systematic investigations carried out in Australia by" the Department of Agriculture, New South Wales, into the food of certain Australian birds are of esper eial interest to New Zealand, as many of the species examined are also found in this country. The inquiry, which resolved itself into au investigation into the character of the stomach and crop contents of the various species, was undertaken with the object of attempting to control the blow-fly pest _i shee'pg as it was realised that some birds"mig_t play an important part-:in keeping these "troublesome ..flies in .check.:: .... It . was^ therefore, decided' to make an examination,: as extensive as possible, of all birds in sheep-breeding, districts which, might affect the 'pest; '■--_ It was found that neither the starling nor the sparrow, both of which are. found in New; Zealand, play any. definite part in controlling the bloW-fly.-pest. 'The -starling was found to: do- marked harm to fruit gardens and some-harm''; to crops, but it did some good in destroying certain insect -pests; such . as ;cntworms, when these are present in abundariee, and perhaps other food is scarce, ,1a addition, the starling - interferes i with, the breeding-places of many. usef til insectivorous birds. The stomachs of seventy-three starlings' were examined. Wheat grains w.ere found>in-a;few and fruit in one; locusts-or;-grasshoppers in five, wirewo.rms ia twp,. ; cutvyorms ia thirty-four, flies in four, psyllids in one, and scale in one. Out one hundred and twenty-seven sparrows examined, sixty-four were found to be feeding oa wheat and maize.: Yarious grass seeds were found in others, and.:white ants, cabbage moth larvae, cutworiiis, locust's, blow-flies, and aphidesiin•.others. The large- amount of gra__ .-eatencf_r:;outweighs, any value'that-ttio'spafrovv^may have as-an. iusectivorous '■■ bird during the period when such .grain, is available! but during other seasons of the year it probably plav-s a mildly useful part. In any case, whether these birds are useful. or»not, :they have .established themselves to such an extent iii'New Zealand that attempts at eradication would have little effect on their numbers. The. little silver-eye, 'white-eye; ringeye, or blight bird," whichever. name takes the fancy, has been "accused of robbing the gardener-of small fruits. The stomach contents of fifty-five showed that forty-five had fed'on vegetable food, - chiefly -ruits of • various : kinds. Thirty-two contained insect ■ food. Amongst the insects eaten . were cabbage moths, froghoppers, ■ psyllids, thrips, aphides, black scale, and plant bugs. -During the fruit season' there is hot the slightest questionI'th_t the silver-eye does considerable damage toorchards in Australia, and by feeding on the fruits of such pests as.the blackberry^ and passing the seeds in their droppings, the silver-eye acts as a potent disseminator of this plant. How- , ever, during the vseason when fruit is not ripe it apparently serves a definitely useful purpose in destroying certain insect pests. As measures to .destroy silver-eyes have never yet;" been successful in materially reducing their numbers in any locality in the Commonwealth there is littie likelihood of eliminating this bird, from any particular part, but means should bo taken to discourage the birds in the fruiting season. In the remainder of the year they wage effective war against many insect pests. However, it is only in the small fruit farming district- of New IZealand that any such action would be justified. The white-eye is not a protected species ia this country. According to the examination in New South.. Wales,: the magpie,: which has beeii introduced into New Zealand, and is now common in many parts, should bo rigidly'protected. In tils country it is included in the list of protected species. Though occasionally eating wheat (in Australia) it is more essentially insectivorous, frequently feeding on locusts or grasshoppers, fly larvae, etc. -The pectoral br^'laiid. rail, which, occurs in New Zealand, appears to" be of some value, as'grasshoppers and cutworms were found in the.stomach coii"tents. ' A pukel-of'wSs... found.-to have fragment- 'of Vegetable;.inatt'erf''in. itstomach, and the r white-headed stilt freshwater "shells, dragon-fly larvae, and water beetles. The food of a whitefronted- heron was crabs and:prawns, and a bittern contained weevils', leaves, and fruits. The investigation showed that' the kingfisher, tho species alsofound in New.Zealand,"-.to lie a useful bird, feeding on locusts and grasshoppers, as well as beetles. Three speeies of owls were examined, and all showed the presence of insect-food.1-They are useful-in destroying grasshoppers and beetles, as well as mice. Some of • the hawks are. useful in preying on mice and sparrows. All the.cuckoos are evidently highly useful insectivorous birds, feeding especially on various" caterpillars. One, for instance, : Had ;tiS-nty-five cutworm larvae in it's fstomSch. In this connection it is interesting, to mote that cuckoos "very closely •'related to New Zealand's" shining '~c__kbo''. were found' to be' feeding "on .moth-'larvae, beetles, bugs, grasshoppers, ant's? larvae of caterpillar^' and of saw 'fly. Incidentally, practicaily: aH": oi- tha smaller species of birds examined were found to. be. of great use as insec>.destroyers. Representatives'•- of some of these birds are also found'iijSew-Zea-land. The robins, akin..t6-ou_ tomtit and wood robin, are valuable insectivorous birds, eating chiefly the smaller sof t^bodied flies,gnats,' small moths, etc. The fantails were shown" tobe eaters of ants,' flies, -beetlesrplaht" bugs; "and asilid flies. The actual crop aiid: stomach contents of eleven magpies were comprised of ants, locusts, or grasshoppers, fly larvae, weevils, hawk moth larvae, cutworm, red scale, and spiders. The rosella, which is present in.one or two. localities in New' Zealand;- is regarded as a pest in apple orchards in parts of Australia, but it is also a consumer of beetles, papae of flies, blowflies, and other flies;, shepherd's purse seeds, maize seeds, grass seeds, and several other kinds of seeds.