214 Clark, Curved-billed a7id Palmer's Thrashers. fibril 



CURVED-BILLED AND PALMER'S THRASHERS. 



BY JOSIAH H. CLARK, 



The following is a comparison of the measurements of the eggs 

 of the Curved-billed Thrasher (yHarporhynchus curvirostris) from 

 Ramos, State of San Luis Potosi, Mexico, where the elevation is 

 about 8,000 feet, with those of Palmer's Thrasher {Harporhynchus 

 curvirostris palmeri) from El Plomo, Sonora, Mexico, where the 

 elevation is about 1,200 feet. 



Having been located as a mining engineer in the above men- 

 tioned localities, I had the opportunity of making a study of these 

 birds. I am aware that the same variety of birds under dif- 

 ferent conditions of altitude or latitude will vary both as to the 

 time of nesting and the number of eggs to a set. So that two 

 men may describe the nesting habits of a bird, and though they 

 may agree as to the composition and position of the nest, they 

 will give a different average for the number of eggs to the set, 

 the date of nesting, and their measurements. 



For example, Mr. G. B. Sennett says the Curved-billed Thrasher 

 along the Rio Grande in Texas commences to breed in March 

 and lays four eggs. Mr, Charles J. Maynard says that it lays 

 four or five. 



1 examined over one hundred nests of this bird during the 

 years 1899 and 1900 and in all only three times were there more 

 than three eggs, and these were, one nest with four young, and 

 two nests with four eggs each. For Ramos I would say that the 

 average was less than three, also their earliest nesting in May, 

 The reason that the birds do not nest earlier is because April and 

 May are the hottest months of the year in this locality, and there 

 is not so much for the birds to eat ; the rains begin in June. An 

 example of late nesting at Ramos is the Scaled Partridge. The 

 natives tell me it never nests before the middle of July, I found 

 nests of fresh eggs August i and August 25. From this it shows 

 how important it is not to rely too much on facts from any one 

 locality, but as these two localities are especially favored by these 

 birds, and as they outnumber all other birds almost two to one, I 

 could not help comparing them, and I would like very much for 



