Hummingbirds are some of the most coveted backyard birds, but what is a hummingbird? What makes these birds so different from other common backyard birds?

Hummingbird Species

There are more than 300 hummingbird species in the world, though the exact species count varies depending on different classification systems and accepted divisions of subspecies and closely related birds. Hummingbirds are actually related to swifts and share many features in common with them, but “hummers” are unique and distinct.

Hummingbird Geography

Raptors, shorebirds, gulls, songbirds and other bird species are found throughout the world, but hummingbirds are only located in the Western Hemisphere. Only a handful of species are regularly seen in North America, though unique species can be found in abundance throughout South America, Central America and the Caribbean. The species that do nest in North America are migratory, though many other hummingbirds stay in the same tropical ranges all year round.

Hummingbird Physiology

The real characteristics that define a hummingbird are physical. Every birder can instantly recognize a hummingbird by its appearance and behavior, as well as the characteristic “hum” the birds’ wings make in flight. Understanding the physical characteristics of hummers can help define what makes these tiny birds special.

• Size: A hummingbird’s diminutive size is one of its most familiar characteristics, and in fact some hummingbird species are the smallest birds in the world. Other species, however, are larger and more robust, though they are still tiny when compared to other backyard birds.
  
  

• Shape: Hummingbirds may look different than other bird species, but they have a similar shape that makes them instantly recognizable. The stubby body, long wings and long, narrow bill are features found in every hummingbird’s shape.
  
  
• Bill: The needle-like bill of a hummingbird is its most unique physical characteristic. The bill is extremely long and thin compared to the bird’s overall size, and it is used as a tube for the bird to lick nectar from flowers, sap wells and feeders with its long and agile tongue.
  
  
• Wings: A hummingbird’s wings are long, narrow and tapered to give it better agility in the air. Even more important than wing shape, however, is its construction – the shoulder and elbow joints of the wing are very close to the body, which allows each wing to pivot and tilt. This is critical for the bird’s ability to change flight directions and hover.
  
  
• Legs and Feet: Hummingbirds have very tiny legs and feet; so small, in fact, that the birds cannot walk. They can manage an awkward sideways hop, but the hummingbird’s primary locomotion is flight.
  
  
• Plumage: Many bird species have bold colors and patterns, but hummingbirds’ overall iridescent plumage is unique. In particular, the brightly colored throat – gorget – of male birds is a key field mark in shape and color. Females are generally plainer but still show iridescent colors for many species.
  
  
• Metabolism: Hummingbirds have the highest in-flight metabolism of any bird species. Their efficient energy conversion is necessary to sustain their rapid heart rate and wing speed, though they can enter a state of torpor when at rest, particularly at night, to conserve energy without constant feeding.

Hummingbird Behavior

Like most birds, hummingbirds have some unique behaviors that help distinguish them from other species.

• Flight: A hummingbird’s flight is its most unusual behavior. Hummingbirds are the only types of birds that can sustain long term hovering, and they are acrobatic flyers that can also fly backwards and change direction almost instantly.
  
  
• Feeding: Hummingbirds eat almost exclusively nectar and insects. While some hummingbirds will experiment with fruit, doing so is usually a way to extract sweet juice similar to nectar and they do not eat the fruit’s flesh. Hummingbirds do not eat seeds even occasionally, unlike many other backyard birds.
  
  
• Pollination: Like many insects, hummingbirds are critical for flower pollination. Many flowers have evolved elongated blooms that require the birds to brush against pollen in order to feed, even with their long bills. As the hummingbirds get pollen on their heads and bills, they transfer it between different flowers and help the plants propagate.
  
  
• Aggression: Many birds are aggressive and will drive intruders away from their territory, but hummingbirds can be among the fiercest birds. This is especially astonishing when their tiny size is taken into consideration, but many birders have observed hummingbirds successfully repelling much larger birds away from their preferred feeders and flowers.

From their geographic distribution to their physiology to their behavior, there are many characteristics that make hummingbirds unique. Understanding what a hummingbird is can help birders better appreciate these avian jewels and make observing them even more enjoyable.

Photo – Anna’s Hummingbird © Joan Gellatly