402 CORACIIFORMES chap. 



simply deposit tlieir eggs on the debris naturally found in 

 cavities. 



To descend to a few particulars, the Snowy and Short-eared 

 Owls, certain other species of Asio, and in some cases the Eagle- 

 Owls (Bubo) breed upon the ground, often near some sheltering 

 tuft, and use little or no bedding ; Speotyto collects a mass of grass, 

 dry leaves, feathers, and rubbish in burrows ; the Wood-Owls 

 {Syrnium), the Long-eared Owl {Asio otus), and several other 

 forms utilize deserted nests of Pies, Crows, Squirrels, and the like, 

 commonly adding a fresh lining ; the first-named alternatively 

 choose holes in trees or in the ground ; while Carine glaux has been 

 known to breed in ant-hills. The Screech-Owl (Strix) and most 

 of the smaller members of the Family deposit their eggs in 

 crevices in rocks or banks, in natural cavities in trees, or even at 

 the junction of two large branches ; towers, lofts, dovecots, and 

 belfries being well-known sites for the former. Apparently none 

 of the above excavate their own holes in the wood, or do more 

 than clear them out ; a few, however, decorate the nests they 

 usurp with green foliage, as do so many Buzzards and Eagles. The 

 habits sometimes undergo a decided change, as when the Short- 

 eared Owl in the Aleutian Islands, and the Screech-Owl in Texas 

 and India take to fairly deep burrows. 



The Strigidae are exceptionally early breeders ; for instance, 

 Long-eared Owls' eggs have been found in England at the end of 

 February, and those of Bubo virginianus in that month in the 

 United States ; it is true the Screech-Owl is later in this country, 

 but this does not seem to be the case with its American race. 

 Where fresh sets are found late in the year, the first have gener- 

 ally been destroyed, and a second brood is uncommon, though the 

 contrary holds true during vole- or lemming-plagues, when food is 

 unusually abundant ; at such times, moreover, the number of eggs is 

 abnormally large for the species. The usual tale varies from two 

 to ten, while the bigger forms as a rule do not deposit so many 

 Much has been made of the fact that the Screech-Owl (with the 

 Eagle-Owl and other forms) lays at considerable intervals of time ; 

 but this is certainly not always true, and in many cases the vary- 

 ing size of the embryo is easily accounted for by supposing the 

 parent to sit as soon as the first egg is deposited. On the other 

 hand, occasional breaks certainly occur in the laying, and pairs of 

 eggs are often produced almost simultaneously ; yet the bird has 



