VOL. XIV.] NOTES OX SLAVONIAN GREBE. 9 



probably never seen its parents, but had taken to the water 

 wholly by instinct. 



On the e\x^ning of July 22nd, tlie two eggs were cold and 

 had not been disturbed since my previous visit, at which 

 time their positions had been carefully noted. However, 

 one of them was " pipped," and I could distinctly hear the 

 voice of the bird within the shell. A search for the parent 

 Grebes was without avail. 



The next morning, although the sun shone upon the nest, 

 the eggs were cold and the foetuses in both of them were dead. 

 No birds were seen. My last visit, on the evening of July 

 24th, yielded no further result. But I noticed now, that 

 there was no water around the nest. It was stranded upon 

 a mud-bar. This was undoubtedly the cause of forced 

 abandonment of the nest. The Grebes were unable to reach 

 it by a water route, and no other mode of travel was possible 

 to them. A search around the water area, now very small 

 and shallow, gave no further evidence. The Grebes were 

 never seen again. 



In reviewing the account of these observations certain 

 groups of data suggest themselves for summarization. 



It is interesting to note that only six days elapsed between 

 the removal of the first set of eggs and the deposition of the 

 first egg in a new nest. 



The period of incubation is twent3'-four or twenty-five 

 days. 



The change of colour which these eggs undergo is also 

 worthy of note. I do not refer to the nest-stains caused by 

 contact with the fermenting vegetation of the nest lining, 

 but to a uniform colour change of the surface layer of the 

 shell, which is brought about presumably by exposure to 

 light and atmosphere. Referring to the eggs of the second 

 nest by numbers it will be noted that egg number two, when 

 first observed at 7.30 a.m. had apparently just been deposited. 

 As previously stated, its colour was a very delicate bluish- 

 green. Egg number one had already attained its final colour ; 

 a sort of drab-tinted buff, which rendered it less conspicuous 

 in the nest. Twenty-four hours later, egg number two had 

 changed to the same colour as egg number one. No data 

 were recorded for egg number three in this respect. Egg 

 number four, after thirty-six hours, was " nearly but not 

 quite the same colour as the others." After it had been in the 

 nest forty-eight hours it was noted as " same colour as other 

 eggs." But egg number five could scarcely be recorded as 

 fully changed after eighty-four hours had elapsed. These 



