NO. I LOCOMOTOR MECHANISMS OF BIRDS — HARTMAN 3 



Roller-Smith balance with a capacity of 1,500 milligrams and a sensi- 

 tivity of 0.02 milligram. Only healthy adult birds were used, except 

 for a few immature specimens which are mentioned in the text. 

 Nomenclature is based largely on Peters' check list (1931-1951) and 

 on the check list of the American Ornithologists' Union (1957) for 

 North American passerine species. The values obtained were listed 

 in tables. In our earlier work some of the muscles were not weighed, 

 which accounts for the lack of complete data in some species. The 

 text figures make comparison of typical values in each family, those 

 preceded by an asterisk in the table being represented. 



Material for this work was collected in Florida, Maine, Ohio, and 

 Panama. Panamanian birds were collected during the period January 

 through March at the following stations : Juan Mina, Canal Zone, on 

 the Rio Chagres ; Rio La Jagua in the Pacora marshes, in the Province 

 of Panama east of Panama City; Cerro Copete (elevation 7,000 ft.) 

 above Boquete, and the finca "Palo Santo" near the village of El 

 Volcan (4,250 ft. above sea level), in the Province of Chiriqui. 

 Florida birds were collected at different seasons on Lake Okeechobee, 

 around the islands of the Gulf Coast, and on the prairies and ham- 

 mocks of the peninsula. Ohio birds were obtained from the central 

 part of the State, and Maine birds were collected at or near Lake 

 Kezar in the southwestern part of the State. Most specimens were 

 obtained in the morning before 11 o'clock. 



ACKNOWLEDGMENTS 



I am very much indebted to Richard Archbold, of the Archbold 

 Biological Station, Florida, for his personal assistance in the collection 

 of material, and for the use of the facilities of the Station. In 

 Panama the studies in the Canal Zone were based at the Juan Mina 

 Field Station of the Gorgas Memorial Institute through the good 

 offices of Dr. Carl Johnson, the director. The La Jagua Hunt Club 

 permitted the use of their facilities for work in the open country near 

 the Rio La Jagua. Pablo Brackney kindly granted our party the use 

 of a cottage at "Palo Santo," and the late Tollef Monniche aided us on 

 our expeditions on Cerro Copete above Boquete. Alois Hartmann also 

 permitted us to stay at his place in western Chiriqui. The late Dr. 

 James Zetek, then Resident Manager of the Canal Zone Biological 

 Area on Barro Colorado Island, was very helpful at all times with 

 advice. I wish to thank Dr. Alexander Wetmore for the identification 

 of some of the Panamanian birds and for a critical reading of the 

 manuscript. Many of the measurements and calculations were carried 



