87 



by reference to the original numbers, and by reference likewise one 

 ought to know whether the clutch has become imperfect by 

 breakage. 



State of Incubation. Also show about the average number of days 

 the bird usually sits. For instance T. musicus, the song thrush. 

 Original clutch number is say 5. The incubation is 5 days or a 

 week, this shows that the thrush commenced sitting when she laid 

 5 eggs. The result of a number of such entries is to prove conclu- 

 sively that a given bird never sits less than X or more than Y eggs. 



Identity. One never ought to take a clutch of eggs until one 

 has seen sufficient of the parent birds to be absolutely dead sure of 

 their identity. In fact, the identity blank always ought to be filled 

 by the one entry " certain both parents seen " or " certain female 

 flushed from nest." There may arise cases when you are quite 

 certain that there were a number of birds of that species nesting 

 in a colony with other birds, as Sterna fluviatilis and Lams minutus 

 do., but cannot be absolutely certain that the nest you have in 

 front of you is that of the bird you think it is, and no matter what 

 pains you take to endeavour to reduce the matter to certainty you 

 are baffled. If you take the eggs you ought to enter under the 

 identity column doubtful nest mixed with nests of so and so and 

 so and so. 



Structure and Situation. A short description, say, of a blue 

 tit's nest. In an old woodpecker's nest — in hole 10 feet up an elm 

 tree, nest of moss, lined with horsehair and pheasants feathers, or, 

 as another example, an actual nest of C. jamiliaris I took some 

 time ago. In a split in an old thorn bush, nest of twigs of birch 

 hazel and oak, lined with the dead stems of Scylla nutans, the root 

 of Triticum repsns, dry stalks of Poa annua, finished with sheep's 

 wool and feathers of Phasianus colchicine, Columba palumbiis, 

 Syrnium aluco, and one feather of Parus caeruleus. 



Eggs received from strange collections should be syringed 

 with carbolic acid diluted to ensure their sterility. 



Arrangement of Eggs. 



A series of circles or ovals cut in cards and placed over a thick 

 layer of wadding filling the cabinet drawers is our own system. It 

 looks exceedingly well and is very safe. Next best system 's a 

 separate glass bottom or glass top circular box, one for each 

 clutch. Ducks eggs must be accompanied by down from the nest to 

 aid identification. . Down should be sterilized before placing it in 

 the cabinet drawers. 



As a last word to you. Never forget rare birds are rare. We 

 very seldom see rare birds ourselves. I warn you that more drivel 

 has been written about birds than any other biological subject I 

 am acquainted with. More casual haphazard records of non- 

 existent monstrosities and imaginary rarities mar our records in 

 this subject than probably any other kindred subject. This loose- 

 ness and unreliability arises from the following causes, amongst 

 others. 



