What Makes a Bird a Bird?

The majority of us can characterize a bird by sight. Our criteria for doing so usually includes: it has feathers and it flies. Must be a bird! Birds have very interesting roots, as they are thought to have evolved from dinosaurs - and have been around longer than 65 million years. Our first human ancestors didn't pop up until MUCH later. 

Eastern Bluebird. Photo by Kristen Martyn. 

There are key features that make a bird, a bird. Birds belong to the class Aves. And are characterized by the following:

1. High Metabolic Rate: If you feed birds, you are no stranger to this one. Birds are so small and so active that they burn calories very quickly, necessitating them to also have a high intake of calories on a daily basis. Certain types of birds, such as hummingbirds, have even higher metabolic rates. Supporting birds by providing high quality and nutritious food, as well as planting supportive native plants can help ensure they are always able to get what they need. 

2. Toothless Beak: but of course! Birds have beaks. The style of the beak can vary quite drastically and depends largely on other life history traits, mainly what the bird eats. Raptors need a sharp beak that can tear prey, ducks and geese need wide rounded beaks for dabbling, and hummingbirds need long slender beaks for drinking nectar.

3. Laying of Hard Shell Eggs: As a rule, birds lay eggs. These also differ quite dramatically in size and shape, depending on life history. They mostly differ due to where the eggs are laid- are they on the ground and need to be camouflaged? Or are they on a cliff that they need to not roll off of? You can learn more about the biology behind eggs in our blog post on the topic here. 

4. Lightweight Skeleton: As you can imagine, if you're going to fly - you need to be light! They also have special struts for strengthening, to essentially help their bones be stronger without being heavier, a detriment to flight. They are also pneumatized, meaning they are full of air. 

Call this the 'it's a bird' checklist! If there was ever any question. 

Warmly, 

Heather