23 DECEMBER 1938, Page 17

COUNTRY LIFE A Trust *Job Among its many activities, its

most beneficent activities, the National Trust now and again offers posts that make the mouth water. Details of one of these have lately been published. The Trust has come into possession of the Calf of Man, a self-contained little island off the Isle of Man. It has some curious likenesses with Ramsay Island, off the coast of Pem. brokeshire. Both islands are cut off by narrow but very dan- gerous straits ; both islands have towering cliffs ; both are the homes of the chough and the peregrine falcon, and both contain attractive, farms. The Calf resembles Lundy Island in possessing two lighthouses, one of which has been converted into a dwelling house and is to let for a short period or a long. A permanent resident is also wanted who will perform the functions of farmer or smallholder, of watcher and of warden. Even Mr. R. M. Lockley, who has a " dream island " and has made himself the chief chronicler of islands, might be attracted.

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New Londoners On the Thames in front of Old Battersea House, which is one of' the best places of pilgrimage on the river, were seen the other• day a pair of lesser black-backed gulls. It has always been a little surprising that the gulls which flock to London have consisted > almost exclusively of the small, almost tern-like black-headed species. They are not accurately named for the head, .w,hich is now white, darkens only to a deep brown in spring.. :The black-backs, both the larger and less large, are rather more accurately named, and there is never any difficulty about their identification. I have seen an occasional herring-gull in London, but no other species except the black-headed. Does the appearance of the lesser black-backs give evidence that the species is multiplying excessively, as many observers have complained, within the last three or four years? It may be so ; but experience suggests that London grows progressively more popular among birds of very many sorts. The river is a potent lure and might well induce the presence of sea-birds. The black-headed species is less marine than other gulls, and some of the nesting gulleries are nearly a hundred miles inland.

* * * * Historical Trees The ,organisers of the Coronation tree-planting campaign, whose headquarters have been the offices of the Council for the Preservation of Rural England, have at last finished their labours. Their record of accomplishment, which gives details of ten thousand of local schemes, is to be presented to the King in the spring, and less magnificent volumes are on sale to the public at 12S. 6d. if bought at once. Trees can be excellent historical monuments, witness Queen Elizabeth's oak in Hatfield Park; but in general their age is very much exaggerated. There is a dragon tree in the gardens of Government House at Gibraltar that is said (on very slight evidence) to be a thousand years old ; and it is popularly held in the island of Majorca that some of the strangely gargoyled olives exceed a thousand years. Have we any tree in England that approaches such an age ? Only two species could compete, the oak and the yew. The oak has been the general favourite of the Coronation tree planters, who would perhaps have laid more stress on the yew if it had not acquired a connexion with mourning. A most pleasing picture of the oak as a tree of memorial is the roadside planting in the park at Perth, in Western Australia. The trees, which were planted in honour of soldiers who fell in the War, took most kindly to the Australian clime, not less kindly than the riverside weeping willows imported from St. Helena. How will their longevity compare with the native gums ? Jarrah, now a frequent rival of oak for making floors, must be long-lived, one would think. It is certainly proof against the particulai enemies that may destroy the magnificent Karri giants of *est= Australia. Among the various attempts to make our people " tree-minded " as the phrase goes, an honoured place belongs to the Roads Beautifying Association. It has issued a calendar, of which the Men of the Trees themselves might be proud ; and it is a singularly useful calendar, for it gives very full lists of garden shrubs and trees that flower month by month. No better lists have been printed. The Association, whose address is 7,Buckingham Palace Gardens, London, S. W.1, has done yeoman work. A Whipsnade Verdict One of the particular pleasures of the Whipsnade Zoo is the little spinney or grove that is used as a sanctuary for wild birds, and for some tame. It contains a number of nesting boxes, and these are numerous enough and have proved popular enough to make possible the collection of statistics that have a more than local interest. Happily the present director of the Zoo, Mr. Julian Huxley, is a good field naturalist ; and his personal interest in the nesting boxes at Whipsnade has elicited some valuable information on the effects of weather on the population of birds. There are good bird years and bad bird years for birds that build in holes or hedges as well as for game birds that build on the ground ; and the difference between a very good year and a very bad year in regard to the population of birds must amount to tens of thousands. The analysis of the issue of the Whipsnade boxes becomes an annual event to which all observers of birds may look forward with eagerness. It may perhaps be inferred—though the inference is not drawn by the analyst—from Mr. Huxley's latest figures that the proportion of hatched young successfully reared is smallest when the clutch is smallest, not inversely, as one might expect. The prophetic bird fears to prepare for a large family when conditions are going to be bad. One of the really bad years was 1897. The number of nests, the size of the clutches, the number of eggs hatched, the number of birds reared were all a good deal smaller than in 1£96. The species especially studied were great tits, blue tits and starlings. If these hole-nesting birds were affected so consistently by season, it seems likely that other birds nesting in less well- sheltered homes would show yet greater deviations. An analysis of the figures for this year will appear in Mr. Witherby's British Birds, which has become a standard official organ for such records.

The Ideal Zoo

The outstanding quality of Whipsnade is that it wipes away the line dividing the wild and the tame. We cannot rival in this humanised island the achievement of a Yellowstone or Kruger's Park, with their lions, bears and the rest ; but we have done more than others for smaller fry. The various sorts of partridge and such fowl that run about in freedom are an introduction to the fenced paddocks where greater creatures can in some measure enjoy " the free play of life," that is one definition of happiness. At the Bronx Zoo, which in some regards is supreme, spectators enjoy the sight of grey squirrels running wild. (Incidentally, they may also see them catch an occasional sparrow, though I am told that my experience in this regard was exceptional.) At Whipsnade brown squirrels have been enlarged ; and perhaps the causes of the strange ups and downs in the numbers of this species may be discovered. Even mammals, like birds, have their good years and bad years. In some species, notably rabbits, as Australian experience suggests, success in reproduction depends a good deal on a sense of security.

Birds and Weathers Migrant birds are most obviously affected by season. I have known a pair of swallows to rear four consecutive families in one season and only one in another. In the worse year they arrived later and built very much later. For some of the migrants breeding is a rush ; and one species, the goatsucker, as it used to bc. called, succeeds in rearing two families only by the device of a sort of maternal sacrifice. The hen bird leaves her babies to the sole charge of the cock while she goes off and lays and broods a second clutch. The bird is here so short a time that no other system is possible if two broods are to be secured. How often do the first young wild- duck perish ; and how often do thrushes desert the first clutch if an untimely snowstorm arrives ! Grouse will sit interminably on a frozen clutch and rear no young if the eggs are not taken. I knew of one merlin that sat for seven weeks on barren eggs. To return to the Whipsnadc Zoo, the brush turkey in the sanctuary, which hatches its eggs by the agency of the heat in a heap of leaves, can only succeed when our summer is more than usually dry and warm. A pair utterly failed the first year of the experiment and thereafter succeeded beyond all expectation in two successive dry summers.

W. BEACH THOMAS.