Hummingbirds have excellent eyesight. They have large eyes in proportion to their body weight. The eyes are set on the side of the head allowing the hummingbird to see both ahead and on the side peripherally. Hummingbirds have many more rods and cones than humans in their eyes. This makes them better able to see colors and ultraviolet light. The ability to see in ultraviolet light enables them to see nectar guides in flowers. Nectar filled blossoms are found by sight, not fragrance.
Bill and Tongue
The long, thin bill is well adapted for retrieving nectar from flower blossoms and for capturing tiny insects. The tongue retrieves nectar by a rapid lapping technique. The tongue is divided, grooved and covered with tiny bristles that collect and hold liquid where it is then squeezed out by the bill and swallowed. A hummer will dart its tongue up to 10 times per second into a nectar source. One can see a hummingbird extend its tongue out of its bill several times after feeding to clear nectar residue from the grooves.
The hummingbird skeleton is perfectly adapted for flight. The bones are porous, a weight reducing adaptation. There is a large breast bone keel to which flight muscles (which are proportionally larger than those of other birds) are attached. The rib cage is made up of eight pairs of ribs rather than six pairs found in most birds. The shoulder is a ball-and-socket joint. Unlike almost all other birds, the “wrist” and “elbow” joints in the wings of hummingbirds are fused. This makes the wings rigid in flight and able to efficiently use the force exerted on them by their powerful flight muscles.
Hummingbirds have the least average number of feathers of any bird family, but they more than make up for their lack in quantity through quality. When hummingbirds are viewed in indirect light they are actually flat, dark colors. The brilliant flashy metallic colors that make the feathers so noticeable come from melanin pigment arrange in flat platelets. The platelets contain tiny air bubbles that act as reflectors and cause the feather to appear iridescent. When light shines directly on a hummingbird feather, some wavelengths of light are absorbed and others are reflected. The feathers appear vibrant, metallic. The most iridescent feathers are on a male’s gorget (throat patch). The hummingbird can position these feathers to reflect in the same direction all at once. This flash of color is used in courtship displays. A hummingbird molts its body feathers once a year in early to midwinter. Wing and tail feathers are replaced annually independent of body feathers. Juveniles obtain their adult plumage by their first winter.
Legs & Feet
Ruby-throated hummingbirds have very short legs which are not well suited for walking of hopping. They function mainly as a grip, used for perching. Hummingbirds are in the taxonomic order, Apodiformes. The name means “without feet,” which is how they look most of the time and is why there is the myth that hummingbirds have no feet.