608 Recent Literature. [^ t k 



were a male Argus Pheasant (Argusianus argus), an adult male Regent 

 Bird (Seriallus chrysocephalus) , a Green-backed Trumpeter (Psophia 

 viridis), a Double-banded Puff-bird (Bucco bicinctus) " probably never 

 before exhibited alive," and a chick of the Galeated Curassow (Pauxi 

 pauxi). Among the birds bred in the Park during the year were three 

 Upland Geese (Chloephaga magellanica) and a Banded Curassow (Crax 

 sclateri) — both apparently first records of the breeding of these species 

 in the United States. The census of birds on January 1, 1919, showed 736 

 species represented by 2,406 individuals as compared with 813 species and 

 2,799 individuals the previous year. The number of species in some of the 

 larger groups in the collection were as follows: Galliformes, 68; Columbi- 

 formes, 61 ; Anseriformes, 54; Psittaciformes, 66, and Passeri formes, 332. 

 The Tropical Research Station in the Bartica District of British Guiana 

 was compelled to suspend field work, but the Director, William Beebe, and 

 the Preparateur, John Tee Van, " spent all the time available in a careful 

 review of past collections and of zoological literature for records of the 

 higher vertebrates of British Guiana, resulting in a preliminary check 

 list " which will be published in the near future. The number of species 

 of birds credited to the Bartica District is 426. An expedition in charge 

 of Director Beebe sailed in February, 1919, to reopen the station on a new 

 and permanent site at Katabo, at the junction of the Mazaruni and Cuyuni 

 Rivers.— T. S. P. 



The Meaning of Natural Control. — In a paper l with this title Mr. 

 John D. Tothill calls attention to the obvious fact that in each generation 

 of any animal, all but two individuals from the total progeny of each pair 

 must perish. This mortality is due chiefly to natural control, and in explain- 

 ing how the natural control of certain insects is accomplished the author 

 makes certain interesting references to birds. 



Among predatory enemies of insects the chief are birds and insects. 

 In the case of the Forest Tent-caterpillar the percentage of destruction due 

 to various enemies is estimated, and chickadees and mites together are 

 credited with the destruction of 25 % of the eggs. Doubtless the major 

 share of these fall to the chickadees. As further examples of the work 

 of birds, the author states that the Cecropia moth in New Brunswick is 

 held in check chiefly by the Downy and Hairy Woodpeckers, and that 

 the Red-eyed Vireo is one of the chief factors in the control of the Fall 

 Webworm. 



In the tabulation of the enemies of the latter insect, birds are credited 

 with a percentage of destruction of the broods, varying in different years, 

 from 11.4 % to 89.5 %. In 1912, when the insect was fairly plentiful, a 

 reduction in numbers was brought about chiefly by parasites (insects). 

 In succeeding years the parasites gradually died out as the insect became 

 rare, and control was maintained almost exclusively by birds. — W. L. M. 



1 Proc. Ent. Soc, Nova Scotia, 1918, pp. 10-14. 



