242 BIRDS' NESTS 



close together as possible on some suitable cliff — a 

 spot where an overhanging ledge furnishes the 

 required shelter from above. Another American 

 species, the Chestnut-bellied Swallow {H. erythrogaster), 

 makes a nest of mud in the form of an inverted cone, 

 the side nearest to the rock to which it is affixed being 

 more or less flat. Incidentally I may mention that 

 various species of Swallows breed in the disused nest 

 of the Oven-bird, forming a bed for their eggs with dry 

 grass and feathers, but whether this indicates a change 

 in the nest-building methods of these annexing species 

 it is of course impossible to say. We might almost 

 presume that these birds have relinquished the habit 

 of forming a mud shell or outer nest when they dis- 

 covered that these mud "ovens" saved them the 

 trouble of making one for themselves. A full descrip- 

 tion of the Oven-bird's curious nest will shortly be 

 given {conf. p. 244). 



The open type of nests of the Tyrant Birds 

 {Tyrannidce) has already been described, but we have 

 now to deal with the various domed nests made by 

 other species in this family. A description of one or 

 two of these must suffice. Mr Richmond has recorded 

 {Proceedings U.S. National Musewn, xvi. p. 504) a most 

 interesting experience of how he found his first nest of 

 the Tyrant Bird named Todirostrum cinereum, by see- 

 ing the little owner of it (after a spirited attack upon 

 an intruding species of Wood-hewer) disappear into 

 what he had supposed to be an accidental tuft of 



