1 62 The Irish Naturalist. August, 



where, I think, the average cltitches of most species are some- 

 what less than in Great Britain. Among the remaining six 

 we have the Magpie laying abotit seven eggs, while her open- 

 nest constructing relatives, the Crows, lay only five ; and 

 the three dome-making warblers each laying six or more, 

 while the Whitethroat and other open-nest-makers of the 

 Warbler family draw the line, as a rule, at five. There remain 

 the Dipper and the House-Martin, which do not, I think, laj^ 

 so man}' as six eggs in Ireland, and it will be necessary for 

 me to return to the subject of these birds before concluding. 

 We see, at any rate, that six of our eight dome-builders 

 possess the distinguishing characteristic of laying large 

 clutches of eggs compared with the builders of open nests. 



Now, supposing that these six birds built open nests like 

 those of the Whitethroat, Hedge-Sparrow, and Chaffinch, 

 would it be possible for any one of them to rear in safety more 

 than five young ones ? It would certainly not be possible for 

 the Wren and Long-tailed Titmouse to rear, as the}^ do, broods 

 of from ten to a dozen. I do not believe that it w^ould be possible 

 for the Magpie to rear seven, or even for the Chiff"-chaff, except 

 in those comparatively rare cases in which its nest is placed 

 quite on the ground, to rear as many as six. As a rule, at 

 any rate, birds that build open nests at a height above the 

 ground limit themselves, though not with great strictness, to 

 clutches of five eggs ; and the reason for their doing so becomes 

 pretty plain when the young have attained a size at which 

 they are nearly, but not quite, ready to fly. A brood even of 

 five then becomes almost too much for the open nest to hold; 

 there is an ever-present danger of " bubbling over," as it is 

 called, and much loss of life actually occurs through some of 

 the little birds tumbling out. I think, therefore, that it must 

 be extremely unusual for a brood larger\.\i2iXi five to be success- 

 fully reared in a nest not protected in some special way against 

 this "bubbling" danger. It is not, I admit, an uncommon 

 circumstance for a bird whose normal clutch is five to 

 "exceed," occasionally, into a sixth, perhaps even a seventh, 

 egg. Any bird's-nesting bo}' may once or twice have ex- 

 perienced the surprise of finding as many as seven eggs in a 

 Blackbird's or a Hedge-Sparrow's nest ; and he is pretty sure 

 to have met with a few cases of six. But it does not follow 



