1916 J HussEY, Spring Birds of La Plata. 389 



times near Conchitas, about midway between La Plata and Buenos Aires. 



17. Circus cinereus (VieilL). Cinereus Harrier. — Seen only 

 twice, both times by a muddy stream south of the city. They seemed quite 

 sluggish in their movements and quite unlike the next species. 



18. Circus maculosus (VieilL). — Larger and darker than the preced- 

 ing and much more active in its habits. It seemed much more common 

 during the cooler months than later in the year. 



19. Rostrhamus sociabilis (VieilL). Snail Hawk. — By far the 

 most abundant large bird at La Plata. I first saw them in August flying in 

 great flocks over the marshes; at times their flight was very suggestive of 

 a Buteo, and at other times they swept low over the grass like a harrier, 

 or perched upon slender willow stalks which bent nearly double under their 

 weight. 



From then until December they were abundant ; but above all they were 

 snail hawks, and as the summer weather approached and the marsh dried 

 up, the snails became more and more difficult to find, and the hawks began 

 to disappear. Finally, on January 16 in a whole day's tramp I did not see 

 a single Rostrhavms; while beneath nearly every post and willow stalk 

 was a pile of empty snail shells, evidences of the bird's previous residence. 



20. Parabuteo unicinctus unicinctus (Temm.). — This hawk was 

 seen but twice. Its actions recalled a harrier, but its flight was more 

 sluggish even than that of Circus cinereus. 



21. Nyctalops accipitrinus cassini (Brewer). Short-eared Owl. — 

 Frequently seen flying low over the higher ground at the edge of the marsh, 

 especially where the grass is fairly short. It seems to fly most about twi- 

 light, both in the morning and evening, yet I have also seen it near noon 

 in brightest sunlight. It is not at all shy, and did not seem to note my 

 approach with any show of fear. I have never heard other notes from it 

 than a loud hooting at twilight. 



22. Tyto flammea perlata (Licht.). " Lechuza." — ^The Barn Owl 

 is resident about the city of La Plata, and though not very numerous, is 

 well known. Its common note is a hissing scream like the sound of escaping 

 steam; on one occasion I heard the cry which Bendire, speaking of T. 

 'pratincola, described as "a feeble, queruloits note like ' quaek-quaek ' 

 or ' aek-aek.' " 



23. Speot3rto cunicularia cunicularia (MoL). — The Burrowing 

 Owl does not seem to be very common about La Plata. I saw a few in an 

 open field south of the city, but no others except when on a trip to Cordoba. 



24. Ceryle amazona (Lath.). "Martin pescador."— Once when 

 I was walking along one of the canals in the littoral forest at Los Talas, a 

 rattling call struck my ear, and on ti'acing it to its author I found this 

 kingfisher. The only other time that I saw it was with several of the next 

 species. 



25. Ceryle americana (Gm.). "Martin pescador." — This little 

 Kingfisher met with onlj- at the Estancia Pereira, about midway between 

 La Plata and Buenos Aires. A small stream has been dammed to form a 



