EASTERN CROW 251 



Wilson (1923) reports a case in which a crow was attacked by a 

 large snake, but such instances are probably rare. 



Among mammals, the crow's greatest enemy is man. Since the 

 economic status has been questioned thousands of crows have been 

 killed by poisoning, shooting, and especially by bombing the populous 

 roosts. A few are killed on the highways by automobiles. 



No comprehensive study of the diseases of the crow has been made 

 to my knowledge, but as has been shown in the case of other species of 

 birds, disease is probably an important factor in the life of the species. 



Mitchell (1929) reported an epidemic of tuberculosis in crows of 

 western Ontario, where he conducted experiments to see if infection is 

 likely to be carried to other animals. Eaton (1903) has given us a de- 

 tailed report of an epidemic of roup in the Canandaigua crow roost in 

 Ontario County, N. Y., during the winter of 1901-2. Eaton estimates 

 that at least a thousand crows succumbed to the disease in that region 

 alone. Dr. Fox (1923) in a pathological examination of 16 crows, found 

 cases of tropidocerca, occasional intestinal cestodes, and a few filaria. 



Dr. E. B. Cram (1927) lists five internal nematode parasites found 

 in the crow. Three of these are found in the proventriculus, the glan- 

 dular part of the stomach, and the other two in the trachea, or lungs. 

 The parasites are as follows: Acuaria cordata (Mueller), found in the 

 wall of the proventriculus; the males range from 10 to 11 and the 

 females 22.5 to 40 millimeters in length. Microtetrameres helix Cram, 

 found in the walls of the proventriculus ; the males of this small worm 

 are 4.9 and the females 1.2 to 1.3 millimeters in length. Tetrameres 

 imispina (Diesing), known only from the female, which is 3 millimeters 

 in length ; this parasite is found also in the proventriculus. Syngamns 

 trachea (Montague), occurring as adults in the trachea and bronchi 

 and as larvae in the lungs ; immature worms have been found in the 

 peritracheal tissue and air sacs ; the males are 2 to 6 and the females 

 5 to 20 millimeters in length. Syngamus gracilis Chapin, found only in 

 the trachea; the males are 3 to 3.3 and the females 8 to 11 millimeters 

 long. 



Harold Peters (1936) lists three lice and one tick as common ex- 

 ternal parasites of the crow. The lice are Degeeriella rotundata (Os- 

 born), Myrsidea americana (Kellogg), and Philopterus corvi (Osborn) 

 and the tick is Haemaphysalis leporis-palustris Packard. A different spe- 

 cies of tick and two species of mites have been found on the southern 

 crow. The tick is Amblyomma americanum (Linnaeus), found in a crow 

 from South Carolina, and the mites are Liponyssiis sylinarum (Canes- 

 trini and Fanzago) and Trouessartia corvina (Koch), found on crows 

 collected in South Carolina and Florida, respectively. 



