18 The Oologisfs' Record, March 1, 1923. 



January 23rd, 1923. 

 Mr. Kenneth L. Skinner, Weybridge, England, 



Ed. " Oologists' Record." 

 Dear Sir, 



I have read Mr. Edgar Chance's challenge or wager regardmg 

 the manner of deposition of eggs by Cuckoos or other parasitic 

 birds, either direct from the oviduct or by depositing by means of 

 the beak after laying the egg outside the nest of its victim. 



Especially gathering data on behaviour and relationship of 

 birds through studies of Oology for the past forty years has enabled 

 me to follow the habits of the American Cowbird [Molothrus aier 

 ater) rather closely, and am a little surprised to find the bird's 

 mode of deposition of eggs very much disputed. Speaking of the 

 finding of Cowbirds' eggs in such nests as Parula Warbler, Bendire 

 says : " It is possible that the egg is dropped in the nest with the 

 beak." Such may be the case in rare instances, but it is more 

 probable that where the parasitic egg is found in a Parula's nest 

 it is one of the more open -entrance type of nest frequently con- 

 structed by this bird. The only nest of the Parula Warbler I ever 

 found in this section contained a Cowbird's egg along with the two 

 of the Warbler ; but in this case the entrance to the nest was almost 

 on top of the structure, and on the whole, abovit as easy of access 

 to the parasitic bird as a nest of the Orchard Oriole. 



I am enclosing a short article giving, briefly, some of my 

 experiences with the egg layings of the Cowbird. I do not know 

 whether this is of any value to your publication, or whether it is 

 against your rule to publish articles of this nature from America, 

 but I send it for your consideration. Very extensive additions 

 could be added giving more of my experiences, and if I should 

 take the time to go thoroughly through our records, undoubtedly 

 other and more interesting data could be cited. As I write, it 

 comes to me that I should have added the Blue-grey Gnatcatcher 

 to the list of species from which I have flushed female Cowbirds. 

 Nests of the Gnatcatcher, being of soft, downy substances, always 

 showed signs of the Cowbird having sat upon the entire top of the 

 same, as the rim was always " mussed " up and torn. 



Yours very truly, 



J. Warren Jacobs. 

 [We gladly publish Mr. Jacobs' article.— Editor.] 



