OLIVE-BACKED THRUSH 187 



drop down from the high road of travel to feed and rest in the friendly- 

 woods and thickets." He recognizes the notes of the olive-backed 

 thrush on migration as different from any other bird with which he is 

 familiar; "a singular mellow and almost plaint-whistle, sweet-toned 

 and far reaching, seems best to describe the calls of this thrush. 

 * * * As I have seen birds" come down to rest as early as 5 a. m., 

 and on the other hand, leave for the night's journey at 6 p. m., it is 

 not unlikely that this species travels the air for eleven hours at a time. 

 If they cover two hundred miles in a night, which is not a maximum 

 figure by any means, their rate of speed while in the air would be 

 slightly over eighteen miles per hour, which, as near as I could judge, 

 was about the speed that the individuals traveling in the early morning 

 were making." All the birds observed over his marked square were 

 flying almost directly southwest, which would be part of an almost 

 straight line from Newfoundland to New Orleans. 



The fall migration is very heavy at times at Point Pelee, Ontario, on 

 the islands in Lake Erie and on Cedar Point, Ohio. At the former 

 point, according to Taverner and Swales (1908), "in September, 1905, 

 the first arrived the 6th, becoming very common the 8th. It dis- 

 appeared that night, but gradually increased again to the 13th, when 

 it fairly swarmed all over the place, then slowly decreased in numbers 

 to the end of our stay, the 16th." And Dr. Jones (1910) says: "On 

 the day of my arrival on Pelee island, August 29, there were none 

 found, nor any the next day in spite of a careful search, but with the 

 first faint dawn of the 31st the peculiar notes of this bird were heard, 

 and the full light revealed hundreds of them in the bushes and every- 

 where in the woods. They remained thus numerous until my de- 

 parture the evening of the next day." 



Mrs. Nice (1931) calls the olive-backed thrush a regular spring 

 transient throughout Oklahoma, but remarks: "The lack of fall 

 records is curious; for seven reasons [seasons?] I followed the fall 

 migration with the keenest interest, but never once saw a thrush of 

 any species." This is additional evidence that this thrush does not 

 always follow the same route on both migrations. Perhaps the main 

 fall flight may cross the Gulf of Alexico to southern Central America, 

 or to South America. Ludlow Griscom (1932) says that, in Guate- 

 mala, "October and November are the main months of the fall migra- 

 tion. November 15 is the latest date for western Panama, and there 

 is one December record for Costa Rica." According to Dickey and 

 van Rossem (1938), it occurs in El Salvador only as a spring migrant, 

 or a "rare midwinter visitant." 



Winter.— The 1931 Check-list says that the olive-backed thrush 

 "winters from southern Mexico to Peru, Bolivia, Brazil, and Argen- 

 tina." But Mr. Griscom (1932) says: "The Olive-backed Thrush 



