NESTING HABITS OF OROPENDOLA — CHAPMAN 373 



proup.'^ Possibly, since their ranp:es arc conterminous, it n»ay 

 prove to be parasitic upon all of them. Whether it also parasitizes 

 other species docs not appear to he known. 



To our scanty knowlodire of the relations between this species and 

 its hosts 1 append a summary of my observations on linrro 

 Colorado. 



In 1026, Cassidix was first observed on January 28; in 1927, on 

 January 10, and in 1928, on January II, or respectively 20, 11 and 9 

 days after the bcirinninc: of nest buildin*;. In 1926 earlier visits to 

 the oropondola colony may have been overlooked for my attention 

 was not then focused on these birds. From the dates mentioned 

 imtil that time in each year when my observations ended, Cassidix 

 was frequently seen in the Zarhynchiifi nest tree. For some periods 

 my records show daily visits and at times several visits each day. 



A female is first recorded as entering]: a nest in 1926 on February 

 4; in 1927, in spite of frequent attempts, one was not seen to succeed 

 until February 25; and in 1928, on January 18. Since on the last- 

 named date the nest entered was not completed, the bird was evi- 

 dently making,' a reconnaissance. As most of my observations were 

 made in the morning the greater number of my records of the pres- 

 ence of Cassidix in the oropendola tree were made before noon. 

 The earliest is at 7.40 a. m. but the species was seen in the colony as 

 late as 6.30 p. m. 



The birds seemed to come from a distance and usually alighted at 

 or near the top of the sand-box tree. Here they would remain for 

 several minutes and then pass from limb to limb and along the 

 limbs toward the Zarhynchus nests selecting, as a rule, those fin- 

 ished or most nearly completed. The earlier visits of Cassidix ap- 

 peared to be for inspection and when attacked by Zarhynchus they 

 quickly retreated and soon took fliglit. Later, when their needs 

 were doubtless more pressing, they persisted in their attempts to 

 enter the oropendola nests sometimes succeeding in spite of the 

 combined efforts of several oropendolas and the resident pair of 

 Lr.gafus to prevent them. On leaving the tree they usually started 

 on an extended flight, sometimes over the lake, that soon carried 

 them out of sight. 



Visits from single birds or twos was the rule, more rarely three 

 were observed together and on February 8, 1927, five females, the 

 greatest number seen togetlier, perched in the tree top. Several at- 



" Tlie recorded spocloa and locnlitips nre as follows: 



Oatinops dccumnnUK. — Soulliprn Brazil, Goeloi, 1894, "Avos do Brazil," p. 284; 1807, 

 This, p. .^.64. British Gulnnn, 1R5)0, Lloyd, TIhk hri. N. S., X. p. 37. 



Oymnontinoiis mont' :umae. — Costa Uica, Crandai.l, 1014. Zooloplrn, I, pp. .330, 341. 



Zarhynchua tca'/leri tcaijJrri. — Costa Klcn, Ciundaii., 1914, ZooIOKica, pp. 338, 342. 



Carious crla. — I'ara, Brazil, Kv.siiF.r-, 1K90, Ibis, p. 585; 1897, J. F. O., p. lOS. Gorldi, 

 1897, Ibl.s, p. 304. Brlti.-ih Gulnna, I.loyd, 1807, Tlmolirl, N. S., XI, p. 5. 



Cadcua hacmorrhoiia. — Brltl.sh Guiana, Li.OYp, 1807, T'niehrl, N. 9., XI, p. (j. 

 28095—31 25 



