The area of insertion of the deltoid muscle is elongated in those birds with shortened humeri; these birds have also greater flight power than do birds with longer humeri and therefore a shorter external condyle. Table 1. Lengths of Arm Bones in cm. =========================+=========+========+======+======= Species | Humerus | Radius | Ulna | Manus -------------------------+---------+--------+------+------- Ptilogonys caudatus | 2.39 | 2.57 | 2.79 | 2.25 Ptilogonys cinereus | 2.24 | 2.48 | 2.78 | 2.38 Phainopepla nitens | 2.21 | 2.59 | 2.82 | 2.39 Phainoptila melanoxantha | 2.40 | 2.51 | 2.70 | 2.25 Dulus dominicus | 2.23 | 2.38 | 2.63 | 2.31 Bombycilla garrula | 2.35 | 2.58 | 2.88 | 2.67 Bombycilla cedrorum | 2.06 | 2.34 | 2.60 | 2.38 -------------------------+---------+--------+------+------- Table 2. Arm-trunk Ratios (in percent) =========================+=========+========+======+=======+======= Species | Humerus | Radius | Ulna | Manus | Total -------------------------+---------+--------+------+-------+------- Ptilogonys caudatus | 85 | 92 | 93 | 80 | 2.58 Ptilogonys cinereus | 84 | 90 | 103 | 89 | 2.76 Phainopepla nitens | 84 | 98 | 107 | 91 | 2.82 Phainoptila melanoxantha | 73 | 77 | 82 | 69 | 2.31 Dulus dominicus | 78 | 83 | 92 | 81 | 2.51 Bombycilla garrula | 69 | 75 | 87 | 78 | 2.34 Bombycilla cedrorum | 67 | 76 | 85 | 77 | 2.29 -------------------------+---------+--------+------+-------+------- Table 3. Arm-trunk Ratios (in percent) =========================+=========+========+======+=======+======= Species | Humerus | Radius | Ulna | Manus | Total -------------------------+---------+--------+------+-------+------- Corvus brachyrynchos | 90 | 101 | 111 | 106 | 307 Dendroica audubonii | 68 | 82 | 90 | 77 | 237 Setophaga ruticilla | 69 | 82 | 91 | 75 | 235 Myadestes townsendi | 71 | 84 | 96 | 81 | 248 Sialia sialis | 72 | 84 | 98 | 86 | 256 Hylocichla mustelina | 75 | 81 | 92 | 80 | 247 Parus atricapillus | 85 | 90 | 106 | 81 | 272 Tachycineta thalassina | 71 | 95 | 107 | 128 | 306 Myiarchus crinitus | 83 | 105 | 115 | 92 | 290 Dumetella carolinensis | 76 | 75 | 89 | 78 | 243 Polioptila caerulea | 85 | 93 | 105 | 71 | 261 Eremophila alpestris | 91 | 99 | 110 | 95 | 296 Muscivora forficata | 85 | 111 | 120 | 108 | 313 -------------------------+---------+--------+------+-------+-------