162 BIRDS OF LA PLATA 



are to be found in one or other of the various groups 

 comprising the Tyran.nidx. 



These birds have no migration, but pair for life, 

 and always remain on the same spot, and will con- 

 tinue to breed in the same hole for many years, even 

 where they are frequently deprived of their eggs* 

 A^ara saw them sometimes uniting in small flocks in 

 Paraguay ; in Buenos Ayres they are always seen in 

 pairs, or, after the young have left the nest, in 

 families. They prefer to live near a human habitation, 

 where there are trees : even one tree, in which they 

 can breed and find shelter at night, will be sufficient 

 to attach them to a dwelling, so great is their par- 

 tiality for the clean-trodden ground where they can 

 freely run about and catch insects. They haunt the 

 cattle-pens, and become extremely familiar with 

 the cows, horses, and sheep, following them to the 

 pasture-grounds, where they are often seen perched 

 on the back of a horse or other domestic animal, 

 or stationed close to its nose on the ground, watching 

 for insects. On the bare ground they run about with 

 wonderful swiftness, and are able to overtake and 

 capture flying insects without rising. The male and 

 female invariably hunt together, and at intervals fly 

 to some favourite perch to indulge in a duet composed 

 of loud, rapid, shrill notes, somewhat metallic in 

 sound. Though able to fly swiftly when in pursuit 

 of a passing Hawk or other bird, at other times their 

 flight is strangely slow ; the round body, short blunt 

 wings and tail giving the bird a somewhat curious 

 appearance as it progresses laboriously through the 



