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Why are Hummingbirds Aggressive?

We've all seen these tiny birds zipping around chasing each other and battling as if it were the clash of the titans. They duel with each other in aerial dogfights and chirp madly while wielding their beaks like miniature sabers. All the while, the feathers are flared and the colors are vivid and intense. So, what is it that causes such a minutiae jewel of a bird to wreak havoc on others of his species? To understand the aggressive behavior of the Hummingbird, we'll have to go back in time and understand the development of the nectar eating bird itself.

The story, according to fossilized remains, begins in Eurasia about 30 to 35 million years ago and 22 million years ago in South America.. There are no fossil records that tie the Eurasian Hummingbird fossils to the South American fossils and Hummingbirds are extinct in Europe, Asia and Africa. What is known is that the fossils found in Eurasia are strikingly similar to today's modern Hummingbirds in the Americas. The similarities include size, the wing bone structure for hovering and the long beak for sipping nectar. These semblances lead scientist to speculate that maybe Eurasian Hummingbirds left Europe for the Americas due to climate change and loss of habitat or maybe competition from other nectar eating birds like African Sun Birds. No one really knows the answer or how Hummingbirds came to be in the Americas. However, one key difference between Hummingbirds and Sun Birds is the wing bone structure of each bird. African Sun Birds cannot hover like the Hummingbird and are considered a "Passerine" or perching song bird. Hummingbirds belong to "Trochilidae" and hover, have weak feet for perching and lack the ability to sing like song birds.

The photo to the right is a photo of one of 6 fossilized remains of Eurasian Hummingbirds. The two key elements that tie the fossil to living Hummingbirds in South America is the beak and a wing bone structure called the humerus. Feel free to click on the photo and read the story.

Hummingbirds are the only bird that has the ability to hover and with it comes an enormous requirement to feed constantly on something high in energy. This is where nectar becomes the ideal and highly prized food source for Hummingbirds. Nectar is a high energy sugar solution produced by flowers and composed of the simple sugars glucose, fructose or sucrose (a disaccharide of glucose and fructose, also known as table sugar) . Flowers produce these in different quantities to entice pollinators like bees, butterflies and Hummingbirds. Bees tend to visit flowers that are yellow, blue or purple and that produce glucose or fructose. Hummingbirds, on the other hand, prefer red, pink or orange flowers which produce sucrose. Estimates for Hummingbird calorie intake are on the order of 6600 to 12000 calories a day or one half their weight in food. As a perspective, a human weighing 100 pounds, would need to consume 50 pounds of food every single day! So, is it any wonder that these tiny birds compete so fiercely for a feeder or a group of flowers? The need for food drives them to defend a territory of nectar sources just to survive.

So, how we can we as humans help Hummingbirds in their struggle for survival? One sure way is to put out Hummingbird feeders. Placing two or several feeders will reduce territoriality and allow for more birds to feed. Be sure to distribute the feeders out of sight of each other to eliminate one bird from monopolizing the feeders. Hummingbirds will defend any flowers or feeders that they can see from a given vantage point. This may mean, placing a feeder around a corner, column or tree from another feeder to ensure that other Hummingbirds have access and will not be driven off by a more aggressive bird.

Planting flowers, flowering shrubs and trees is another way to provide nectar for Hummingbirds as well as nectar for other pollinators. Shrubs and trees will also provide nesting and roosting spots for Hummingbirds and other species of birds. Check with your local plant nurseries for the best varieties for your planting zone. We also have a section on our Blog with Educational and Informational Links for Hummingbirds on plants, planting zones and garden ideas. Find the Education and Information section here:

Flower gardens have another benefit for the Hummingbirds in that they provide the tiny insects that the birds feed on like, aphids, spiders, gnats, mosquitoes and flies. These insects provide the protein that Hummingbirds need to stay healthy, thrive and reproduce. Plus, spider webbing from spiders is what the female Hummingbird uses to construct her nest. The webbing is strong and flexible and the nest itself will stretch as the babies grow.

We hope this has been a useful Blog in explaining the fierce territoriality of Hummingbirds and their need for high energy nectar and insect protein. Let us know if you enjoyed this Blog or have questions or comments. We always welcome feedback and are open to discussion, ideas and topics. Until next month, Happy Birding!

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