26 



THE OOLOCJIST 



PREPARATION OF FAR-INCUBAT- 

 ED EGGS 



For the benefit of newer oologists, 

 one repeats, here, with some ad- 

 ditions, a suggestion made some time 

 ago, in regard to the Preparation of 

 Incubated Eggs. As a rule, of course, 

 wlien we find eggs opaque, we 

 graciously leave them to hatch. But 

 when one finds a beautiful set of Le 

 Conte Sparrow at the very hatching 

 point, one hates to see them lost to 

 the enrichment of oological treasur- 

 ing. If such an experience falls to 

 you, try this: Carefully, with a darning 

 needle, prick out, on the less-finely 

 marked side of the egg, an area as 

 small as possible; yet large enough to 

 admit of the dra^ving of the embryo 

 through the opening, with a hook. It 

 is really surprising through how small 

 a hole an embryo can be removed, if 

 not too far advanced to completion. 



A large bent pin, attached to a 

 wooden handle, makes a perfect em- 

 bryo hook. With this, turn the em- 

 bryo about, in the egg, until the back 

 of the head appears. Then draw it 

 out, with extremest care. 



The placenta usually presents grave 

 difficulty. It clings to the shell. It 

 must be coaxed out. This may often 

 be done with a strong jet of water, 

 through ones blow-pipe. With caution, 

 the hook may be used. The placenta 

 having been removed, rinse the egg 

 thoroughly; and lay it to dry on some 

 hard surface. When it is utterly dry, 

 tear out a' section of tissue paper, of a 

 suitable tint; providing a margin wide 

 enough to grip the edges of your open- 

 ing fairly. In applying this, on the 

 point of a darning needle, gently press 

 down the edges of the paper smoothly. 

 In preparing the patch, use glue,— 

 good, strong glue. NOT mucilage. 

 Wlien this patch is dry, make another, 

 somewhat larger. With an indelible 

 pencil, affix the species-number, the 



set-mark and, if you care, your own 

 private hall-mark, and apply this 

 patch over the other. Use especial 

 care in pressing and smoothing the 

 outer patch. Firm adhesion can only 

 thus be secured. 



When the patch is dry, with your 

 darning needle spread over it a thin 

 layer of collodion. With larger eggs, 

 this treatment should be repeated. You 

 will find that the ether in the collo- 

 dion brings out the color of the indel- 

 ible pencil finely. (By the way, why 

 not use such a pencil, always, in mark- 

 ing your eggs? It involves less danger 

 of denting a fragile egg if you will 

 moisten the surface, evenly and thin- 

 ly: and then lightly mark the legend. 

 In this wise you assure the impossi- 

 bility of some dishonest pseudo-orni- 

 thologist making up sets by erasing 

 the common-pencil markings ) 



A concrete example of the above 

 sort of treatment for eggs with ex- 

 tremely large emptying holes is add- 

 ed, here: 



Last June, in a little meandering 

 swale, I found a robbed and deserted 

 nest of a Montana Red-wing. It was 

 set a foot above the slowly-running 

 water. The new nest was just 

 finished; and was quite like the for- 

 mer nest. It was but a rod distant. 



In the abandoned nest were two per- 

 fect eggs and one that had been part- 

 ly eaten by some small bird or mam- 

 mal. In the water below was another 

 egg with a small hole in one side 

 through which almost the entire con- 

 tent had been removed; still another 

 that had almost all of one side crushed 

 in. One of the perfect eggs was of 

 rare beauty, all marked at the apex 

 with delicate stripplings and hair-lines 

 of dull-brown. The five eggs were all 

 of them mutually so unlike that one 

 might have imagined that the female 

 Red-wing had "made up" a set by 

 stealing from other nests! 



