6. COLLECTING EGGS 35 



6. COLLECTING EGGS 



There is less reason for collecting eggs now than there was in the past, 

 unless the collector is in a region in which the nidification of many species is 

 unknown. When eggs are taken the collector must make sure that he has 

 correctly identified the nesting bird. Serious errors have been caused through 

 collectors assuming that a bird near a nest must be the owner of it. It may 

 be necessary to collect the bird on the nest to be certain of identity. 



Preservation of eggs 



The only part of the egg which is usually preserved for collections is the 

 shell. This is saved by removal of the contents, preferably when the egg is 

 freshly laid. The contents are removed through a hole in one side (not in the 

 end) opposite the side which it is considered most desirable to show, so that 

 the egg can be exhibited with the hole concealed beneath it. A neat hole 

 can be made with a drill, and small conical drills which could be used to 

 produce holes of varying size were available in the past but are now more 

 difficult to obtain. The larger sizes of drills used in dentistry can be employed 

 for this purpose. If nothing else is available a small hole may be chipped in 

 the side of the egg with a suitable sharp pointed instrument. The hole 

 should be large enough for the contents to pass out leaving the eggshell clean. 

 In small eggs the hole might be c. 1-2 mm. in diameter, and in larger eggs 

 c. 3-5 mm. There has been a tendency for collectors to blow an egg through 

 the smallest possible hole, but for scientific purposes it is better to make a 

 larger hole and ensure that the shell is properly clean than to make a tiny 

 hole through which the contents will not completely pass. 



The contents of the shell are blown out through the hole with a blowpipe, 

 the tip of which is inserted into one side of the hole. The blowpipe is a small 

 tube, and it is most convenient to have one which tapers and curves upwards 

 towards the end. It may be of metal but can easily be made by drawing out 

 and bending the end of a glass or plastic tube. In the field, if nothing else is 

 available a hollow grass-stem may be used. The egg is held hole-downwards, 

 preferably over a bowl half-full of water to make subsequent disposal of 

 contents easier. The tip of the blowpipe is inserted into the hole, and by 

 blowing firmly into the other end, and by moving the tip slightly and adjusting 

 the pressure of air used, it should be possible to blow out the contents of the 

 egg. It may be necessary to prick the yolk with a needle to make it run more 

 easily. 



Clean water is then drawn into the egg either by filling the blowpipe with 

 water and blowing it in, or by immersing the egg, hole uppermost, and 

 drawing out the air with a blowpipe. The water is then blown out to rinse 

 the shell. This can be repeated if necessary. The shell is placed on some 

 absorbent material, hole downwards, to dry, being moved from time to time 

 and inspected. A watch should be kept for traces of yolk on the outside of 

 the shell which, if not wiped away while liquid, will cause the shell to adhere 

 to other objects as it dries. Once it is dry, data can be entered on the shell 

 (see section on labelling, p. 39). At all stages the empty eggshell is very 

 fragile and must be handled with great care. 



If the contents of the egg are rotten great care should be taken in drilling 



