1SS4. 1 Bakkovvs on /iii(/s nf the Lotvcr Uruiiuay. Ill 



• This species was also ahuiulaiU at J^ahiu lilaiica and along the 

 Sierras to Carhiu'. 



136. Elanus leucurus ( VicilL). — A rather scarce resident. 

 I noted it onh- about twenty times in the course of as many 

 months. It was oftcnest seen in winter. 



137. Rostrhamus leucopygus {Sp/x). — Apparently not 

 common, as it was only taken twice — both times in summer and 

 in swamps where Ampullaria abound. 



I once saw at Concepcion a flock of fifteen or twenty small 

 Hawks hovering over the interior of a swamp}' island, and pre- 

 sume they belong to this species as they were not "Chimangos," 

 and I never saw^ anv other species congregate in this way. 



13S. Milvago chimango {lleilL). Chimango. — By far 

 the most abundant of the birds of prey, it being no unusual thing 

 to have thirty or forty in sight at once. They take the place of 

 our Crows, walking about in the plowed fields, collecting around 

 the slaughter-houses or any dead animal in the fields, haunting the 

 margins of the rivers, and keeping an eye on all exposed bird's 

 nests. They are very unsuspicious, and being seldom shot at, may 

 be approached, at almost any time and place, without any precau- 

 tions. They are credited (doubtless correctly) by some writers 

 with nesting on the ground, but this does not seem to be true of 

 them at Concepcion. I inquired carefully of the natives, and was 

 invariably told that they nested "•like tne Carrancho," in trees. 



On September 26. I saw^ a pair carrying sticks to a tree in 

 which there was a partly completed nest, but the birds dropped 

 the sticks on finding themselves observed. Again on November 

 6, I found in a tree a nest of sticks in which were the shells ot 

 several eggs precisely like those brovight me by natives as veri- 

 table eggs of the Chimango, as I believe they were. 



Considering the abundance of the birds, and their familiarity, 

 it seemed strange to me that although I frequently searched in 

 many localities, both on the ground and in trees, I never dis- 

 covered an occupied nest of this species. As before stated, how- 

 ever, during the spring months I was often unable to give more 

 than half a day per week to field work, and this will, perhaps, ac- 

 count for many oversights with regard even to common birds. 

 The eggs which I obtained w'ere miniatures of those of the fol- 

 lowing species. 



139. Polyborus tharus (J/c/.). Carrancho (meaning un- 

 known). — Abundant and well known everywhere, but appearing 



