the collecting of rare birds

1
258 CORRESPONDENCE IBIS 111 other types of netating behaviour. The period fm,m ‘I first appearance of a Wren cannot be equated with the duration of nest-site selection . As ringing Wrens promptly on their first appearance in standing woodland is extremely difficult it would be interesting to know the method employed to obtain the Wren data in Table 1. The breeding behaviour of the Wren is so different from that of turdines that to include it in generalizations about them is unsatisfactory. EDWARD A. ARMSTRONG. 23 Leys Road, Cambridge. 14 November 1968. THE COLLECI’ING OF RARE BIRDS SIR,-h a recent letter (‘ Ibis 111 : 113) Dr. Harwin wrote: “A mist-netted bird, which is afterwards liberated, means, in the last resort, no more than a sight record.” Is it not true that, in the last resort, there must be an element of trust in the acceptance of all records? The case of the Hastings rarities demonstrated to the satisfaction of many ornithologists that a skin in a cabinet does not necessarily constitute indisputable evidence. Like juries, ornithologists evaluating records have to satisfy themselves beyond reasonable doubt, and we know of no good grounds for rejecting mist-netting as a means of providing satis- factory evidence. Today skilled ringers produce plumage descriptions, measurements and wing formulae of live birds which are in every way as detailed and accurate as those taken by museum taxonomists. They may, if necessary, detach specifically diagnostic feathers, and also collect ectoparasites-which may be host specific. They can, of course, take close-up photographs of the bird itself, but additionally, by photographing the bird in the hand against a recognizable back- ground, lend powerful support to the $rcumstances and authenticity of their claim. No doubt the determined ‘I forger will always find a means to falsify a record, but happily such people are rare. When dealing with the remainder, that element ;f scepticism which,? the healthy reflex action of most scientists should not lightly be taken for reasonable doubt , ROBERT SPENCER. ROBERT HUDSON. British Trust for Ornithology, Beech Grove, C. J. MEAD. Tring, Hertfordshire. 21 February 1969. Note In line 18 of the lette; by Dr. Harwin, and lines 2-3 of the letter by C. W. Benson et al. in the January number (‘ Ibis 111 : 113), the following correctio?,should be made: for “Allen and Brudenell-Bruce read “Allen et al. (‘ Ibis 110 : 211-212) . In connection with the above correspondence, which is now closed, we have learnt that one of the swifts was mist-netted in July 1968 and was identified as Apus cufle~. Full details appear in ‘Ardeola’ 13 (1969): 115-127. The opportunity may be taken to stress that the principle is not disputed by any of the signatories of the various letters, that where bird populations are very small or otherwise threatened con- riderations of conservation must take precedence over collecting. ED.

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Page 1: THE COLLECTING OF RARE BIRDS

258 CORRESPONDENCE IBIS 111

other types of netating behaviour. The period fm,m ‘I first appearance ” of a Wren cannot be equated with the duration of nest-site selection . As ringing Wrens promptly on their first appearance in standing woodland is extremely difficult it would be interesting to know the method employed to obtain the Wren data in Table 1. The breeding behaviour of the Wren is so different from that of turdines that to include it in generalizations about them is unsatisfactory.

EDWARD A. ARMSTRONG. 23 Leys Road,

Cambridge. 14 November 1968.

THE COLLECI’ING OF RARE BIRDS S I R , - h a recent letter (‘ Ibis ’ 111 : 113) Dr. Harwin wrote: “A mist-netted bird, which is

afterwards liberated, means, in the last resort, no more than a sight record.” Is it not true that, in the last resort, there must be an element of trust in the acceptance of all records? The case of the Hastings rarities demonstrated to the satisfaction of many ornithologists that a skin in a cabinet does not necessarily constitute indisputable evidence.

Like juries, ornithologists evaluating records have to satisfy themselves beyond reasonable doubt, and we know of no good grounds for rejecting mist-netting as a means of providing satis- factory evidence. Today skilled ringers produce plumage descriptions, measurements and wing formulae of live birds which are in every way as detailed and accurate as those taken by museum taxonomists. They may, if necessary, detach specifically diagnostic feathers, and also collect ectoparasites-which may be host specific. They can, of course, take close-up photographs of the bird itself, but additionally, by photographing the bird in the hand against a recognizable back- ground, lend powerful support to the $rcumstances and authenticity of their claim.

No doubt the determined ‘I forger will always find a means to falsify a record, but happily such people are rare. When dealing with the remainder, that element ;f scepticism which,? the healthy reflex action of most scientists should not lightly be taken for reasonable doubt ,

ROBERT SPENCER. ROBERT HUDSON. British Trust for Ornithology,

Beech Grove, C. J. MEAD. Tring,

Hertfordshire. 21 February 1969.

Note

In line 18 of the lette; by Dr. Harwin, and lines 2-3 of the letter by C. W. Benson et al. in the January number (‘ Ibis 111 : 113), the following correctio?,should be made: for “Allen and Brudenell-Bruce ” read “Allen et al. (‘ Ibis ’ 110 : 211-212) .

In connection with the above correspondence, which is now closed, we have learnt that one of the swifts was mist-netted in July 1968 and was identified as Apus cufle~. Full details appear in ‘Ardeola’ 13 (1969): 115-127.

The opportunity may be taken to stress that the principle is not disputed by any of the signatories of the various letters, that where bird populations are very small or otherwise threatened con- riderations of conservation must take precedence over collecting.

ED.