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 

 (Tyrannidcs) 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 Museum, 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 



