HL Deb 24 April 1969 vol 301 cc604-20

5.6 p.m.

LORD SOMERS rose to ask Her Majesty's Government whether the experiments on birds, described in the Daily Telegraph of March 26, are likely to have any benefit on the community; and, if not, why the Home Secretary permitted them to be made. The noble Lord said: My Lords, I beg to ask the Question which stands in my name. In the Daily Telegraph of March 26 last there appears an account of an experiment on, I think it was, twelve chaffinches I had better read the account so that your Lordships will know what I am talking about: Experiments at Cambridge University in which chaffinches were artificially deafened, were undertaken to discover how the birds learned to sing, it was said yesterday. The tests at the sub-department of animal behaviour, a part of the Department of Zoology, are described as' monstrous' in the Shooting Times. Mr. Richard Porter, technical officer of the Royal Society for the Protection of Birds, said yesterday:' They were to find out if birds learned through hearing to sing or whether this ability is instinctive. ' I don't know what the findings were.' As the experiments were done under a licence from the Home Office the Society did not condemn them, he said. 'About twelve birds were involved. It is unfortunate of course. I know it has created a lot of bad feeling among the public. 'But we have problems a thousand times greater to contend with, such as birds being caught in oil slicks.' Nobody at the university laboratories in Modingley near Cambridge, would talk about the experiment yesterday. That, I think, is all I need to read of it.

I think that one of the most surprising things about this account is that Mr. Richard Porter, the official of the Royal Society for the Protection of Birds, did not condemn the experiments, simply because they were done under licence from the Home Office. Either an experiment is worth while or it is not. Even the Home Secretary is only human and is capable of making mistakes, like any other human being. I do not think that the mere fact that it was done under licence should be a reason for not objecting to it. He went on, as your Lordships have heard, to talk about the problem of oil slicks.

I have said before in your Lordships' House that I have no objection to experiments on animals where those experiments are going to bring benefit to the health and well-being of the human race; but this one it seems to me was in a very different category. I am not going to deny Mr. Porter's statement that the problem of oil slicks is a much greater one, but the two problems are totally different. The menace of oil on the surface of the sea is very great and thousands of birds suffer every year as a result of it. None the less, its presence is accidental, though no doubt we should do a great deal more to prevent it from happening. The experiment we are discussing to-night, my Lords, was no accident. This was a deliberate, cold-blooded act. And to what purpose? Simply to satisfy idle curiosity. The human race will not be one iota the better off or the more healthy for knowing the answer to this question.

In any case, the answer has already been found. My noble friend Lord Cork and Orrery, who has told me that unfortunately he will not be able to be present in the Chamber for this debate, showed me a book written by a very eminent ornithologist, Heinroth, and I should like to read two paragraphs from that book. It is not a new publication; it was published in 1959. It has been shown that most of the true song-birds can imitate strange sounds, even though they have only simple songs themselves. Some of them learn their own songs by imitation, others do not. The song of the chiffchaff and grasshopper warbler is innate, as I found by raising them indoors. Even some of the birds with a very elaborate song can produce it without ever having heard it before—blackbirds and song-thrushes, for example. In the autumn a young hand-reared song-thrush weaves into his own practising all sorts of sounds he has heard from other birds, and the result is a stream of warbling gibberish. My Lords, as a musician I can quite appreciate that and realise what the result is. But when spring comes, he produces distinct phrases which are quite recognisably thrush—though perhaps not very good thrush—and in which the borrowed sounds art: arranged into thrush rhythms. Chaffinches learn rather more of their song. Without any examples to listen to, they produce a song which sounds very unlike a wild chaffinch's but has some of the same rhythm. Normal chaffinches differ individually in the details of their songs; these details they learn from their neighbours in their first spring. One may say that they are handed on by tradition from generation to generation.

My Lords, that is a very authoritative account of how birds learn to sing and how they vary. Since that is already known, what is the purpose of this experiment at Cambridge; an experiment done in a far less humane way since the author of this book reared birds naturally from the egg, though keeping them in captivity of course, and did not deafen them or do anything like that? My Lords, I do not know very much about this experiment. I do not know how the birds were deafened so I cannot say how humane or inhumane it was. None the less, one has to remember that animals suffer a great deal more by instinct than by reasoning. The mere fact that they could not hear, that they were confined arid had not their natural freedom would be quite apparent to them by instinct, but not by reason.

As we all know, the Home Secretary is in a very difficult position. He has "cannon to the right of him", and "cannon to the left of him", and they are all volleying and thundering. On one side he has the scientists clamouring to do various new experiments, some of them very necessary ones and a great many more totally unnecessary. On the other side he has the animal protection enthusiasts who can sometimes, as I well know, be nothing short of fanatical. I should like to make it plain, my Lords, that I mean some of them—not all of them by a long shot—and a small minority at that. Unfortunately, it is the small and noisy minority that gets publicity in the Press and is heard about and read about. As I say, the Home Secretary is only human, and with all he has to cope with I should think it would be surprising if he did not sometimes make a mistake. I shall be interested to hear what the noble Lord, Lord Stonham, has to say about this subject. He has always been extremely patient with me when I have brought my problems to him and I sincerely hope that he will show that I have not been wasting your Lordships' time to-night. I shall listen with attention to what he has to say.

5.17 p.m.


My Lords, I am sure that all those interested in the proper treatment of wild creatures will be grateful to the noble Lord, Lord Somers, for having drawn attention to the range of problems, of which this is one. It is true that a good deal of uneasiness has been felt and expressed recently about the experiments carried out, with no control and on a large scale, by American investigators who deprived birds of water to see what would happen. They came to the conclusion that the birds had not died of thirst but of dessication. That distinction made no difference whatever to the birds, and I agree with the noble Lord, Lord Somers, that it makes very little difference to or confers very little benefit on anybody else. But I think that these particular experiments are in a different class.

I venture to think that the noble Lord, Lord Somers, goes too far and unduly narrows the field of scientific experiment when he makes as the test some direct benefit to the community—that is to say, to the human community. In the present case I should have thought it was a matter of very real scientific interest and importance to know how far birds' song is wholly innate and how far it is capable of being developed or learnt from various sources. Despite the authorities he has quoted I do not think that it would be agreed that those matters have yet been statisfactorily determined.

It may be difficult to see how far knowledge of this kind can be of immediate value in relation to human development, but may there not yet be much to be learned from the study of other animals in our efforts to understand the physical and neurological basis of our own potentialities by realising fully how these are developed? In this particular matter, birds are the obvious field for experiment, because, so far as we know, no other mammal except man has a potential of extending his vocalisation or imitating sounds emitted by any other animal. Therefore, if progress is to be made, it is essential to do it in relation to birds.

I understand that the experiments undertaken by Professor Thorpe were upon a small number of birds—some 20, I believe—which were completely anæthetised when part of their hearing was removed, and that was done under careful and properly understood techniques. It is also interesting to know that the effect upon the birds seems to have been entirely to their hearing. They behaved, mated and paired, and even brought up their young families, without any sense of difficulty, until the young birds reached an age when they depended upon clamouring for food to get this from their parents. At that point, of course, their parents, being unable to hear the clamour, did not make the ordinary responses. Perhaps I should mention one other point. These birds, having had their faculties impaired to some extent, were kept to finish out their lives under aviary conditions and were not let loose into the world where, of course, they would have been subject to many added risks through lack of hearing.

I venture to think that the licensing system, as administered by the Home Office in this kind of matter is very carefully and effectively administered, but no doubt that is a matter on which the noble Lord, Lord Stonham, will be able to give your Lordships some assurance. Apart from that, Professor Thorpe, with whom I am well acquainted, is not only a scientific investigator but also a keen bird lover and bird protectionist, and I am sure that none of the experiments carried out under his supervision would either be scientifically pointless or merely repetitive of something that is already well known or in any way would inflict unreasonable damage to the birds themselves.

Therefore, though in general I would share the uneasiness of the noble Lord, Lord Somers, at indiscriminate ill-directed experiments upon birds or any other creatures without a proper control, I feel that in this particular case the charge of inhumanity or cruelty, or just of a wasting of scientists' time, does not really lie against Professor Thorpe and his colleagues. Having said that, I would add that, as a protectionist, I think, that the noble Lord does a real service in reminding your Lordships and other people of the need for some proof, not that the results of these experiments will be directly beneficial to human needs, but that they have a scientific value and are not undertaken, like depriving the birds I mentioned of water, just to see what happens and then describe the result.

5.26 p.m.


My Lords, perhaps I should start by revealing the fact that I am a member of the Advisory Committee of the Home Office which has referred to it from time to time applications for experiments which are considered to be possibly undesirable for various reasons. Also as head of the Royal College, I have had to sign numerous applications for licences for animal experiments and I have also held such a licence myself. Whether your Lordships look upon these facts as a qualification for my speaking in this debate or as a declaration of interest, I leave to your Lordships.

I want to say at once that I have a built-in aversion to all animal experiments, though I completely accept that they are absolutely necessary to medical and scientific progress. Therefore, I share with the noble Lord, Lord Hurcomb, a very considerable sympathy with the point of view put forward by the noble Lord, Lord Somers, who questions the justification on ethical or scientific grounds for certain experiments. It is in this way that those of us who have the duty of granting licences and supervising the conduct of experiments are kept continually reminded of the responsibility of our task.

Animal experiments are of various kinds. They vary in severity from a mere prick to a major operation and from inflicting rather negligible and transient pain to depriving an animal of some essential faculty. Their purposes also vary, from those at one end of the scale directly concerned with the investigation of a specific illness to those at the other extreme, which are designed to reveal the underlying mechanisms of animal physiology and behaviour with a view to building up scientific knowledge, the value of which to the amelioration of man's suffering and handicaps may not at once be obvious.

It is clear that the experiments to which the noble Lord has directed our attention are well into the second category and do not lead at once to new ways of overcoming the handicaps of defective hearing and speech, though in the course of time they may help to do so. The noble Lord has asked whether the experiments are likely to be to the benefit of the community. If we accept that science, including medical science, cannot advance without the continuous exploration of basic mechanisms, then we cannot necessarily answer the question as at present framed, and perhaps this is because this is the wrong question.

One may ask then whether I am justifying all animal experiments simply because we cannot always tell in advance just what the benefit to the community may be. I would not assent to that, of course. I think that the discerning scientist knows, and that those who guide him should also know, whether the question to which he seeks an answer is basic and important to medical or biological science or whether he is merely contemplating a badly planned experiment unlikely to give more than an uncertain answer to a question of trivial importance. This I think is the question which should be asked in this particular case, and I myself would answer it in quite definite terms: that the experiments were designed to throw fresh light, not simply a repetition of knowledge already determined, and did in fact throw light upon fundamental questions concerning the relative importance of instinct and of learning in the development of vocal patterns of communication. As the noble Lord, Lord Hurcomb, has told us, these birds were not confined to artificial conditions. They were in an aviary with other birds, and the behaviour of the deaf birds was clearly not distinguishable from the behaviour of the other birds to any person who simply observed their behaviour in the aviary.

One must, even so, consider whether the severity of a certain experiment is too great to justify its use even if the aims are of importance biologically. I would say that here again I think we are on the right grounds in this experiment, which was so carefully controlled and supervised. Only a certain limited number of experiments have been performed, and Professor Thorpe tells me that there is no immediate intention of doing any more experiments of the same nature.

All those who know something of the history of science realise that the second category of experiment, that which is devised to throw new light on basic problems, may in the long run turn out to be of more importance to the community than the experiment in which the immediate gains and limitations are more obvious. I should like to end by quoting from what the great Michael Faraday said of his experiments on electro-magnetism and induced currents. He said: I have rather been desirous of discovering new facts and new relations depending on magneto-electric induction than of exalting the force of those already obtained being assured that the latter would find their full development hereafter. He left it to others to find the applications of his work to all kinds of present day technology, including communications by submarine cable. For all these reasons, I believe that the experiments that we are considering to-day were justified, and that the Home Office were right to permit them. Nevertheless, I add to what the noble Lord, Lord Hurcomb, said my gratitude to the noble Lord, Lord Somers, for raising the point.

5.33 p.m.


My Lords, twelve weeks ago your Lordships declined to give a Second Reading to a Bill prohibiting the export of animals. In my speech, before advancing reasons why I thought that the Bill should be rejected, I gave what I thought was convincing evidence of my own love of animals and detestation of cruelty to those creatures that we wrongly call "dumb creatures". This did not protect me from a stream of sharply abusive letters. Indeed, one was so sharply abusive as to say: "I killed many men during the prohibition days in the United States and during the war. I am 70 years of age, and I would cheerfully kill you, as I have not much to lose." The stream of letters has now dwindled to a trickle, but it still continues even after such a lapse of time.

Every weekday, I suppose, for the past eight or nine months I have written letters to Members of Parliament who have written to me on behalf of their constituents asking what are the Government's intentions towards the implementation of the Report of the Littlewood Committee. I must have written some 200 to 250 letters of that kind. So I am acutely conscious of the great importance of this subject to the people of this country. The fact is that the British, to their credit, just cannot stand the unnecessary infliction of pain on animals. Nothing more quickly excites our anger; and I must confess that my own immediate reaction to the story in the Daily Telegraph, that some chaffinches had been deafened in an attempt to find out whether they learned to sing through hearing or whether they do so instinctively, was: who cares? Who wants to know?

I therefore join with other noble Lords in thanking the noble Lord, Lord Somers, for his public-spirited action in raising this Question, particularly as it gives me the opportunity to give the full facts, fairly and objectively, and in this way to remove, I hope, the anxiety which has been needlessly and unwittingly aroused. In the process, I hope to convince the noble Lord, Lord Somers, that when he said that this was a deliberate cold-blooded act, and asked to what purpose it was performed—was it simply to satisfy idle curiosity?—he was wrong; and that when he said the human race will not be better off for this experiment, he was also wrong. But that does not abate my gratitude to the noble Lord for raising the matter.

I want also to clear up some of the misunderstandings that appear to exist about the operation of the Cruelty to Animals Act 1876 under which experiments on living animals are at present controlled. I hope that noble Lords will forgive me if I deal with this at some length because, important as the particular Question that the noble Lord has raised is to all the people in this country, the whole matter of experiments on animals is of vastly greater importance, and something of this may be conveyed to people who are very anxious about it. In the course of their inquiry the Little-wood Committee found several widely held misconceptions about the Act and its administration, and they discussed these in some detail. Therefore, before turning to the actual experiments which are the subject of the noble Lord's Question, I should like to remind the House of the control that is exercised over experiments on living animals, and the purposes for which the Cruelty to Animals Act permits such experiments to be performed.

The Act regulates and restricts experiments calculated to cause pain to any living vertebrate animals. The restrictions imposed are designed to ensure that no animal under experiment suffers severe pain that is likely to endure or suffers avoidable pain of any kind. The Act does not define "experiment" or "pain", but for the better protection of animals the Home Office (and I am grateful to the noble Lord, Lord Hurcomb, for his kind words about the way my Department administer the Act) have interpreted these terms "experiment" and "pain" widely. Thus, in practice, any procedure upon an animal designed to find the answer to a problem—other than diagnosis in the course of ordinary normal veterinary practice—is regarded as an experiment; and it is considered to be subject to the Act if it presents even the risk of discomfort or interference with the animal's normal state of health or wellbeing. I think we shall all agree that this interpretation of "experiment" or "pain" could scarcely be wider than it is.

The Act lays down precisely the purposes for which such experiments may be performed—and I shall have more to say about this in a few moments. But first I would assure your Lordships that no person can perform an experiment without obtaining a licence from the Home Secretary. No applicant is granted a licence unless he is recommended by two persons holding offices specified in Section 11 of the Act. One of these must be the president of one of the learned societies named in the Act. The noble Lord, Lord Platt, indicated in his speech that he, as the President of the Royal College of Physicians, was one of those heads of learned societies, and he signs many such certificates; and the noble Lord, Lord Florey, in fact signed this particular certificate, as the President of the Royal College of Surgeons, I believe, which permitted this experiment. That is one. The other signatory must be the professor of a branch of medical science. This guarantees that licences are granted only to highly responsible, qualified people.

In any experiment performed under licence alone the law requires that the animal must during the whole of the experiment be under the influence of an anesthetic of sufficient power to prevent it from feeling any pain, and if pain is likely to continue after the effects of the anæsthetic has ceased, or if any serious injury has been inflicted, the animal must be killed before it recovers from the anæsthetic. Where these restrictions would necessarily frustrate the object of the experiment the Act provides for them to be relaxed at the discretion of the Home Secretary by virtue of one or more certificates to that effect given by the statutory signatories whom I have mentioned; that is, persons holding the offices required to sign applications for licence.

All places where experiments under the Act are performed are also required to be registered by the Home Secretary, and these premises are regularly visited, without prior notice, by one of the ten Home Office inspectors to ensure that the requirements of the Act are being properly observed. That is the general position.

I now turn to the aspect of this matter which bears particularly on the Question asked by the noble Lord, Lord Somers; that is, the purposes for which experiments may lawfully be performed. Subsection (1) of Section 3 of the 1876 Act is quite explicit. It says: The experiment must be performed with a view to the advancement, by new discovery, of physiological knowledge, or of knowledge which will be useful for saving or prolonging life or alleviating suffering. Thus an experiment is permissible under the Act for the advancement by new discovery either of physiological knowledge or of knowledge which will be useful for saving or prolonging life or alleviating suffering. The pursuit of fundamental physiological knowledge is itself enough, without the need to demonstrate any evident or direct usefulness to mankind or animals to be sought from the experiment. The Littlewood Committee gave very careful attention to this point, and to the argument that Section 3(1) of the 1876 Act also implies that the Home Secretary is responsible for adjudicating—which again was implicit in the noble Lord's Question. He said twice (I am grateful to him for it) that the Home Secretary is only human. I say that he is very human indeed. But they gave particular attention to the question of the responsibility of the Home Secretary for adjudicating on the usefulness of a proposed piece of research. They concluded that the interpretation which we put on that subsection was undoubtedly correct, and they rejected the contention that the Home Secretary is responsible for inquiring into the likely value to be derived from specific experiments.

I do not want to keep your Lordships for too long, but it may be helpful if I remind you what the Littlewood Committee said in this context. They said—and I am quoting from their Report: It was strongly contended by witnesses for the Royal Society for the Prevention of Cruelty to Animals and by several correspondents that it was the clear intention of the Act that experiments should not be permitted unless they were essential to solve some specific problem of human or animal suffering. The Home Office has always acted on the view that the phrases"— that is, the phrases I have just read out— describe alternative classes of purpose for which experiments are permissible. We have no doubt that this is the correct interpretation and that the Home Office is bound to allow experiments for the advancement of fundamental knowledge. … We noted that the Royal Society for the Prevention of Cruelty to Animals also took Section 3(1) to imply that the Secretary of State is responsible for adjudicating upon the usefulness of a proposed piece of research or for assessing the results of scientific work. … Home Office practice is to establish that each application for a licence or a certificate is for a class or purpose permitted by the Act. … If, however, the application prima facie satisfies the general requirements of the section, the Home Office has no further concern to assess the potential value of the proposed research or the results of past research. Thus the Littlewood Committee. There is no question whatever, therefore, that in the view of the Littlewood Committee my Department in these matters is pursuing absolutely and scrupulously the correct and proper procedure.

The Littlewood Committee also gave careful consideration to evidence presented about "unnecessary" experiments, so-called, and the need for imposing restrictions in any future Act on the performance of experiments not directly aimed at solving some specific problem of suffering. In paragraph 270 of their Report they said: From our study of the evidence about unnecessary experiments and the complexity of biological science we conclude that it is impossible to say what practical applications any new discovery in biological knowledge may have later for the benefit of man or animal. Accordingly, we recommend that there should be no general barrier to the use of animal experimentation in seeking new biological knowledge even if it cannot be shown to be of immediate or foreseeable value. On this principle we think the formula in subsection (1) of Section 3 should be retained. So, my Lords, the Littlewood Committee, besides endorsing the established view that the present Act does not restrict experiments to those likely to have direct or foreseeable benefit to mankind or animals, recommended no change in the underlying principle. I invite your Lordships to ponder the wisdom of those conclusions and, in particular, the impossibility of predicting the practical benefits that may at any time, and often quite unexpectedly, be derived from what may appear to be pure research.

I have in my hand a letter, dated April 17, this month, from the Audiology Research Unit of the Royal Berkshire Hospital, Reading. It says: Dear Professor Thorpe, We are doing some work here at Reading on the effects of auditory stimulation before birth"— of course, in talking about "before birth" it refers to human babies— and during the first weeks of life of both human beings and animals. One of our major concerns is to discover the effects of deprivation of auditory experience on the development of speech reception and language ability. I have read with great interest of some of your recent work and wondered if you would be kind enough to allow me to visit your Department to discuss techniques with you or your colleagues. If you can accommodate this venture perhaps you will be kind enough to suggest a convenient date. That is one example, which happens to have come into my hands this afternoon, of just one of the results.

In every field of endeavour, not least those of medicine and biology, practical advance would have been greatly retarded, and humanity deprived of many of its greatest benefits, without the constant and ever-increasing pool of knowledge which pure research has accumulated. My Lords—and I hope that the noble Lord, Lord Somers, will accept this—there is no question (I have been into this matter very carefully) but that the experiments involving the deafening of chaffinches constituted genuine scientific research. They were carried out at Cambridge University, as your Lordships have heard, nearly five years ago by Professor Thorpe working in conjunction with a visiting American professor.

Professor Thorpe is the Director of the Sub-Department of Animal Behaviour at Cambridge University. He is one of the most eminent zoologists in the country, and as such he was a member of the Brambell Committee which inquired into the welfare of animals kept under intensive systems of livestock husbandry. For that Committee Professor Thorpe produced a memorandum on The Assessment of Pain and Distress in Animals, which appears as Appendix III of the Brambell Committee's Report. It is a model of enlightened appreciation. I mention this merely to underline the fact that this project was carried out under the direction of a senior scientist who not only is one of the leading authorities in his field but, in the words of my noble friend Lord Hurcomb, is certainly very concerned about animals. Perhaps anything I have said on this subject is completely outshone by what Lord Hurcomb has said. I regard him as the doyen of bird lovers and bird protectors, and if he is satisfied in this matter then certainly I am.


My Lords, may I interrupt the noble Lord? I quite agree with everything that he has said about my noble friend Lord Hurcomb, and I also agree that this was an absolutely genuine experiment, but I wonder whether the noble Lord would not agree with me that there may possibly be occasions on which it is better for us to remain ignorant.


Possibly, my Lords, but this is not one of the occasions. The Press reports about these experiments—and I make no complaint about them—referred to their being performed to ascertain how birds learned to sing. To put it mildly, that was a very superficial description of the purpose. While the experiments were immediately directed at an ornithological problem in connection with Professor Thorpe's work on the ontogeny and vocal communication in birds, they were far from being merely of ornithological interest. They were in fact of wide biological importance in that they were designed to throw light upon the method of formation of neural templates in the brain. They were thus of fundamental importance to students of brain mechanisms. So far as is known, birds are the only animals, apart from man, which have the power of vocal imitation; hence the use of chaffinches in this particular experiment. In man, vocal utterances are monitored continuously by the ears. If the feed-back through the ears differs from that which the speaker utters, gross distortions of speech may occur. The occurrence of imitation in birds provides an opportunity to study the role of feed-back in vocalisation in a situation which, because of the stereotyped nature of birdsong, is much simpler than that in man.

The experiments gave a definite answer to the questions posed. The results were made known at a congress in 1966 and have since been published in ornithological publications. The answers were in fact these: the deafened adult birds continue to sing, but birds deafened as juveniles could not develop the overall song structure. The curious thing is that these experiments only came to the notice of the public because Professor Thorpe, in remonstrating wish an American ornithologist (as I think my noble friend Lord Hurcomb has suggested) for carrying out severe procedures on birds which provided no scientific information of value, contrasted this with his own very different procedure in 1964–65. I hope this disposes of any suggestion that Professor Thorpe was cruel.

In all, 20 chaffinches were used in these experiments. They were taken from the wild, some as nestlings and others as adult birds, under a licence—as I think the noble Lord said—issued under the Protection of Birds Act by the Nature Conservancy. They were rendered deaf by means of a minor surgical operation, carried out under full anæsthesia under the authority of a licence and certificate B granted under the Cruelty to Animals Act. Certificate B refers to an experiment carried out under anæsthesia, where the animal is not killed before it recovers from the influence of the anesthetic. The birds were therefore subsequently allowed to recover from the effects of the anæsthetic.

Both the report on the experiments which has been made by Professor Thorpe, and the observations of the Home Office Inspector (who has nothing but praise for the conditions under which the birds are kept) confirm that within a day or two of the operation the birds were entirely normal in their appearance and general behaviour and showed no signs whatever of suffering any pain or distress as a consequence of being deaf. As my noble friend Lord Hurcomb has said, they are mating normally, and producing fertile eggs, but because of their deafness they cannot themselves alone rear their young to final maturity. Deaf birds would, of course, be at a disadvantage in the wild in avoiding certain predators and would be unlikely to survive. For this reason none of the birds used in the experiment was released; as required by law, after the full results of the experiment were known, they were killed.

My Lords, before I sit down I would say that I deplore the fact that since the news story was published some individuals, who doubtless would call themselves bird lovers but whose conduct proves them to be the reverse, broke open the aviaries and released some doves and budgerigars. Unfortunately, some of these birds have already been killed by predators; all the remainder will either be killed by predators or will starve to death. I can only hope that other people who might feel inclined to take similar action will in future take the trouble to get the facts right first, as the noble Lord, Lord Somers, has done. These experiments were for a scientific purpose and they were properly carried out. They were successful in producing definite answers to the ques- tions posed, and the results of the work have been published. Since the series of experiments was completed in 1965, no similar experiments have been made by Professor Thorpe and he has no proposals to repeat them.