Respiratory and Heart Rates of Birds at Rest

The respiratory rates of birds are inversely METHODS related to their body weights (Groebbels 1932; Salt and Zeuthen 1960).Odum ( 1945) In this study respiratory frequencies were noted that birds breathe at lower frequencies measured by direct observation and heart than do mammals of similar weights.Neither rates by observation of pulses in arterial catheof these observations has been expressed ters, using a stopwatch and hand tally.Most quantitatively.birds had been in captivity for several weeks.The respiratory and heart rates of mammals Air temperatures during the observations were can be predicted from empirical equations 22-26C.Smaller and more excitable birds given by Adolph (1949) and Stahl (1967) were observed through one-way plastic winwhich express the resting rates as functions dows or peep-holes in curtains while they of body weight.The utility of comparable were in cages or compartments appropriate for their sizes.The birds were not handled equations for birds prompted the collection during the observations and were free to move and analysis of appropriate data.Data on within the compartments.respiratory and heart rates were obtained Unfortunately, published values for respirafrom the literature and from additional obser-tory rates are not usually accompanied by vations on 11 species.complete information on the experimental My intention in this report is not only to situations.The selection of data used in this provide a first approximation for such predic-report consisted of excluding values when tions, but also to recommend that collection there was an indication that any one of the of data on respiratory rates and heart rates above criteria had not been met.However, in the absence of complete information, all of be made under more rigorously standardized these criteria may not have been met in some conditions than has been the case previously cases.Equations were fitted to the data by (and reported in conjunction with body the methods of least squares, after logarithmic weights).Reports by Odum ( 1945) and transformations of the data according to the Lewis (1967) are models to follow in this method of Simpson et al. ( 1960).