Factors Contributing to the Destruction of 

 Birds' Nests and Eggs 



By IRA N. GABRIELSON, Portland, Oregon 



FOR a number of years, I have made it a habit to record the cause of the 

 destruction of birds' nests whenever such cause is positively known. 

 To accumulate any considerable data along this line necessarily re- 

 quires that one be in a position to visit nests in the same territory at frequent 

 intervals. 



During 19 14 and 191 5 such opportunity was presented to me, and I gathered 

 most of these data at that time. My record now includes fifty nests on which 

 I have been fortunate enough to secure positive data. It will, of course, be 

 understood that a large number of nests were found destroyed which could 

 not be included because of lack of definite records regarding them. For example 

 on one day I discovered eight Brown Thrasher nests — all of which had con- 

 tained eggs the previous day — destroyed. All were located in gooseberry 

 bushes and had evidently been destroyed by some bird or mammal, as bits of 

 shells were found in the bottom of each nest. 



The following list shows the kinds of nests and gives detailed information 

 regarding the destruction of each : 



Blue-winged Teal. July 8, 1907. Webb, Iowa. Cut into by mowing-machine and 

 eggs broken. 



Bittern. July 12, 1909. Webb, Iowa. Five young killed by mowing-machine. Dis- 

 covered after passage of machine. 



Spotted Sandpiper. June 2, 1914. Marshalltown, Iowa. Washed away by flood of June 8, 



Mourning Dove. May 8, 1910. Sioux City, Iowa. Robbed by boys. May 23, 1910. 

 Sioux City, Iowa. Location of nest unknown to me until I passed close by. The old bird in 

 her fright threw both eggs from the nest as she left. 



Cooper's Hawk. April 30, 19 10. Sioux City, Iowa. Nest destroyed by farmer whose 

 chickens the Hawks were getting. I was attempting to secure photographs of the nest and 

 young at the time and on a return trip found them gone. I happened to mention this to a 

 farmer living nearby and he told me he had destroyed the nest. 



Black-billed Cuckoo. June 2, 1914. Marshalltown, Iowa. Two eggs. Filled with 

 mud and water by flood of Iowa River on June 8. 



Yellow-billed Cuckoo. June 29, 1914. Marshalltown, Iowa. Saw fox squirrel destroy 

 this nest. 



Hairy Woodpecker. June 28, 1914. Albion, Iowa. Three young killed by felling of 

 stub for firewood. Nest location unknown until after stub fell. 



Kingbird. June 23, 1909. Webb, Iowa. Young killed by exposure to storm. Found 

 parent bird on nest afterward, but young dead; nest and young both soaked. 



Phcebe. April 23, 1910. Sioux City, Iowa. Eggs taken and nest torn down by boys. 

 Saw fresh tracks made by boys in mud when I arrived. 



Western Meadowlark. May 15, 1911. Sioux City, Iowa. Robbed by boys. Found 

 the boys with eggs in their possession shortly after they had taken them. June 5, 1914. 

 Marshalltown, Iowa. Parent bird and seven young found drowned in nest after flood of June 

 8 subsided. June 5, 19 14. Marshalltown, Iowa. Three young. Found drowned after flood 

 of June 8. 



Red- winged Blackbird. July 21, 1910. Webb, Iowa. Nest cut down by mowing- 



(136) 



