Table 1 The hummingbird’s tracheal dimensions are relatively shorter than in other birds.

From: The vocal organ of hummingbirds shows convergence with songbirds

 

Bee Hummingbirds

Zebra finch

White-rumped SwiftletC

OilbirdD

Body mass (BM in kg)

0.0035–0.01

0.015

0.010

0.419

Trachea length (TL in cm)

0.88 ± 0.12

3.3*

2.2

11

Expected tracheal lengthA

(in cm)

TL = 16.77 *BM0.394

1.8–2.7

3.2

2.72

11.9

Tracheal diameter (TD in cm)

0.09

0.12

0.15

4.4

Expected tracheal diameterA

(in cm)

TD = 0.531*BM0.348

0.074–0.106

0.12

0.11

0.39

  1. This appears not to decrease the air space volume since bronchial length is much longer than in other small birds (Fig. 2). Expected tracheal length and diameter were calculated based on a model developed by Hinds & Calder57.
  2. AHinds and Calder57; BDaley and Goller67; CSuthers and Hector42; DSuthers and Hector43.