" This Martin is never seen to alight on the ground or on the roofs of houses, but 

 solely on trees ; and when engaged in collecting materials for its nest, it sweeps down 

 and snatches up a feather or straw without touching the surface. It breeds only in the 

 clay-ovens of the Oven-bird (Furnarius rufus). I, at least, have never seen them breed 

 in any other situation after observing them for a great many summers. An extraordinary 

 habit ! for, many as are the species that possess the parasitical tendency of breeding in 

 other birds' nests, none of them confine themselves to the nest of a single species except- 

 ing the bird I am describing. It must, however, be understood that my knowledge of 

 this bird has been acquired in Buenos Ayres, where I have observed it ; and as this 

 Martin possesses a wider range in South America than the Oven-birds, it is more than 

 probable that in other districts it builds in different situations. 



" On arriving in spring each pair takes up its position on some tree, and usually on 

 a particular branch ; a dead branch extending beyond the foliage is a favourite perch. 

 Here they spend much of their time, never appearing to remain long absent from it, and 

 often, when singing their notes together, fluttering about it with a tremulous uncertain 

 flight, like that of a hovering butterfly. About three weeks after first arriving they 

 begin to make advances towards the Oven-bird's nest that stands on the nearest post or 

 tree ; and if it be still occupied by the rightful owners, after much time has been spent 

 in sporting about and reconnoitring it, a feud begins which is often exceedingly violent 

 and j>rotracted for many days. 



" In seasons favourable to them the Oven-birds build in autumn and winter, and 

 breed early in spring ; so that their broods are out of their clay-houses by the end of 

 October or earlier ; when this happens, the Swallow that breeds in November quietly 

 takes possession of the forsaken fortress. But accidents will happen, even to the 

 wonderful fabric of the Oven-bird. It is sometimes destroyed and must be rebuilt ; or 

 its completion has perhaps been retarded for months by drought, or by the poor condi- 

 tion of the birds in severe weather ; or the first brood has perhaps perished, destroyed by 

 an opossum or other enemy. November, and even December, may thus arrive before 

 some pairs have hatched their eggs ; and it is these unfortunate late breeders that suffer 

 from the violence of the marauding Swallows. I have often witnessed the wars of these 

 birds with the deepest interest ; and in many ovens that I have opened I have found the 

 eggs of the Oven-birds buried under the nests of the Swallows, iifter the Swallows 

 have taken up a position near the coveted oven, they occasionally fly towards and hover 

 about it, returning again to their stand. By-and-by, instead of returning as at first, they 

 take to alighting at the entrance of the coveted home ; this is a sort of declaration of 

 war, and marks the beginning of hostilities. The Oven-birds, full of alarm and anger, 

 rush upon and repel them as often as they approach ; they retire before this furious 

 onset, but not discomfited, and only warbling out their gay, seemingly derisive, notes in 

 answer to the outrageous indignant screams of their enemies. Soon they return ; the 

 scene is repeated ; and this desultory skirmishing is often continued for many days. 



" But at length the lawless invaders, grown bolder, and familiar with their strength 



2 H 



