November, 1912. 



KNO\VLi:nGi:. 



437 



sides of the head, and, especially in those species which fly 

 rapidly, are freciiiently extended so as nearly to meet in front. 

 In Diopsis, however, the position of the compound eyes is very 

 peculiar, beinK placed at the ends of rigid stalks, or horns, 

 e.\tending from either side of the head and sometimes as wide 

 apart as the entire length of the insect itself. These stalks 

 also bear the antennae which are short and three-jointed, 

 placed near to the eyes, the terminal joint bearing a long hair 

 which probably acts like the whiskers of a cat by informing 

 the bearer when there is danger of contact with objects in 

 their vicinity. 



Our illustration (Figure 469) shows the insect complete, 

 magnified six diameters, and represents Diopsis apicalis, 

 from Natal, and the head and 

 eyes more highly magnified 

 after having been prepared 

 for microscopic examination 

 by treatment which has ren- 

 dered them translucent, and 

 enables the nerves to be well 

 seen which convey the sen- 

 sations to the brain from the 

 eyes and antennae. 



The reason for this curious 

 arrangement has not been 

 clearly explained, as but 

 little is yet known of the 

 life history or habits of these 

 insects ; but the native who 

 captured the specimen from 

 which our drawing is made 

 hazarded the opinion that 

 as Diopsis is usually found 

 on blades of grass growing 

 near the river, it is enabled 

 in this way to see what is 

 going on beyond the leaf I 



R. T. L. 



Figure 469. 



Diopsis apicalis, from Natal. The complete insect X 6 

 diameters, and the head and eyes more highly magnified. 



ORNITHOLOGY. 



By Wilfred Mark Webb. F.L.S. 



THE BRENT VALLEY BIRD S.ANCTUARV — AX 

 EXPERIMENT IX BIRD PROTECTION.— As mentioned 

 in the column last month the writer, in his capacity as Secretary of 

 the Selborne Society, gave an account of the work which had 

 been carried out during the past few years in the Brent Valley 

 Bird Sanctuary to the Conference of Delegates of the Corres- 

 ponding Societies of the British Association at Dundee. As 

 the paper may be of interest to our ornithological readers, it 

 is here printed : — 



" The difficulties of administering the Wild Birds' Protection 

 Act are well known ; but it is possible for individuals and 

 societies, with a little trouble, to do something towards preserv- 

 ing birds, and it is an experiment in this direction which I 

 am going to describe. 



'■ Some eight or nine years ago it was suggested at a 

 Committee Meeting of the Brent Valley Branch of the Selborne 

 Society that some steps might be taken to protect the Nightin- 

 gales, which were known to nest in a wood of about nineteen 

 acres lying between Ealing and Harrow, which comes within 

 the boundary of the London postal district. A small sub- 

 committee of three members, of whom I happened to be one, 

 was appointed to make arrangements, if possible, for the wood 

 to be watched in the nesting season. 



" As a result, it became part of the duties of a farm-hand 

 to attend to warn off bird-catchers and bird's-nesting boys. 

 After a year, however, the Committee took over the wood, 

 employed a watcher of their own, and kept up the hedges with 

 their own hands. But th'ough success was attained in 

 other directions, the nightingales were not heard for several 

 seasons ; in fact, not until the appointment of the present keeper, 

 who is engaged all the year round, and takes a particular 

 interest in his work. 



" I may say now that the wood is composed of oak trees 



with coppice below, chiefly consisting of hazels, though there 

 arc many other trees and shrubs represented, and these have 

 grown to a considerable size in places that have not been 

 regularly cut every so-many years. 



" Among the common birds that build as a rule are the Song 

 Thrush, Missel Thrush, Blackbird and Hedge Sparrow ; but 

 there are often special points ot interest concerning even them 

 with regard, for instance, to the material of the nest, its 

 position, and variations of the eggs. 



" As a rule, too, from the beginning there have been each 

 year a Chiffchaff's nest and several Willow Warblers'. The 

 Garden Warbler and Whitethroat always breed and so does 

 the Lesser Whitethroat. while the Turtle Dove builds every 

 year. We have only once 

 followed the development of 

 the young cuckoo, though the 

 eggs were found in the wood 

 before it was protected. We 

 have had on one occasion a 

 wild duck's nest; but the 

 parent birds were most prob- 

 ably shot outside the confines 

 of the wood. 



'■ The Long-Tailed Tit at 

 one time was common and 

 it is almost the only bird 

 that has not increased in 

 numbers. The Wren is 

 numerous and builds in the 

 open or under cover in empty 

 tins or old kettles which may 

 or may not have been put 

 up for the purpose. The 

 Robin is another bird which 

 has the habit of making its 

 nest sometimes in natural 

 and sometimes in artificial 

 surroundings. 



"It is noticeable, however, 

 that with the exception of an occasional pair of Blue 

 Tits, one of which nested in a hollow branch, none of 

 the birds which conmionly build in holes, except the two 

 already-mentioned, were found to nest. This, no doubt, 

 was owing to the fact that the oak trees in the wood are 

 young and sound. 



"At the beginning of one season, however, my boy took it 

 into his head to make some rough nesting boxes with large 

 openings and, that summer, nests were recorded of the 

 Flycatcher, the Great Tit. and the Tree Sparrow. Then 

 other boxes were made with various-sized openings, and of 

 more careful construction. These succeeded marvellously 

 well. Blue Tits and Coal Tits built, the Tree Sparrows and 

 Great Tits increased in number and the Wrens and Robins 

 made use of the bo.ves as well as of the tins and kettles. The 

 Nuthatch made its appearance and has been a resident in the 

 wood ever since. Experiments were also made in the way of 

 open boxes for Flycatchers, while trays for Blackbirds and 

 Thrushes, which were fastened to the trees, found favour with 

 some birds, in spite of the almost unlimited possibilities for 

 their building in the undergrowth. Some of the visitors, whom 

 we admitted sparingly in those days, asked us to make 

 nesting boxes for them. The reputation of these dwellings 

 spread, and as we were only too anxious to retain the services 

 of our custodian, we were glad to be able to keep him busy in 

 the winter, and the profits on the boxes went towards the 

 expenses of the wood. It soon became evident that improve- 

 ments could be made in the nesting boxes. For gardens also 

 it might be advisable to have something a little less artificial 

 looking. The only boxes on the market made from natural 

 logs, with which we were acquainted, were those designed by 

 Baron von Berlepsch. 



'■ To these we found several objections : — 

 " (1 ) First of all they were manufactured in Germany. 

 " (2) The idea of making them harmonize with their sur- 

 roundings was not carried through, because there was a piece 

 of ordinary board screwed on to the top of the log. 



