CATBIRD 345 



bronzed grackles. W. L. Burk (1938) relates a case of a catbird that 

 built a nest and laid one egg. A brown thrasher removed the egg, 

 appropriated the nest, and reared its brood. W. M. Orford (1929) 

 writes that a pair of cardinals that appeared in a thicket containing 

 a newly built nest of a pair of catbirds repeatedly chased the rightful 

 owners away and took possession of the nest. The cardinals added 

 new nesting material and apparently settled down to use the structure. 

 When the nest was visited 2 days later it contained a single egg of the 

 cowbird and was deserted. 



Casualties. — H. B. Wood (1934) and others report catbirds being 

 killed on the highways by speeding motor cars. H. F. Lewis (1927) 

 reports that catbirds w^ere killed by flying into various lighthouses 

 during the time of migration. Several of the lighthouse keepers along 

 the coast of Maine have told me that catbirds are frequent victims at 

 their stations during the migratory flights. Robert Overing ( 1938) , in 

 reporting on the 1937 fall migration at the Washington Monument, 

 mentions the catbird as being killed by flying into the structure. These 

 instances lend support to the view that the catbird flies chiefly at night 

 during its migration and spends the daytime resting and feeding in 

 preparation of the next leg of its journey. Weather also proves to be 

 a factor in the mortality of the species. A. T. Wayne (1899) writes 

 that a large number of birds including the catbird perished during 

 the great cold wave of February 13-14, 1889. Mrs. G. W. Trine ( 1940) 

 states that catbirds were killed by a terrific wind and hailstorm at 

 Eed Cloud, Nebr., on June 22, 1940. 



Diseases and parasites. — Bird banders who have trapped catbirds 

 have found them subject to certain diseases. T. E. Musselman ( 1930) , 

 in his banding operations at Quincy, 111., trapped a catbird that had 

 both legs badly diseased up to the tarsal joints. He writes: "Heavy 

 cellular proliferation resulting in grayish crusts and knots nearly 

 doubled the size of the bird's legs. So burdensome were the incrusta- 

 tions that the bird could fly only with gi*eat effort and walking was 

 practically an impossibility." H. A. Allard (1930) writes concerning 

 a catbird with a deformed bill observed in his garden at Arlington, 

 Va. The bill was deformed in such a way that the upper mandible did 

 not close upon the lower in a normal manner. The bend of the upper 

 mandible was somewhat past the middle toward the nares and formed 

 an angle of about 45° with the plane of the lower mandible, exposing 

 much of the inside of the mouth and tongue. He did not see it feed 

 but the bird appeared well nourished and lively. 



The majority of catbirds are infested by a few and some by many 

 external parasites. H. S. Peters (1933, 1936) reports the catbird to be 

 host to the louse Myrsidea incerta (Kell.) ; the two bird flies Ornltho- 

 myia avicularia (Linn.) and O. anchineuria Speiser; the two mites 

 Liponyssus occidentalis Ewing and L. sylviarwm (C. & F.), and the 



