Bird nerd: Beak geek!
A quick stroll around the Zoo can allow you to see the immense diversity of birds just by looking at one key anatomical feature – their beaks. Although birds aren’t the only organisms who get to claim the possession of this structure – see Testudines (turtles, tortoises, and terrapins) and Cephalopods (squid, octopi, and cuttlefish) – they are arguably the most recognized for having taken the structure and making it their own.
Technically, the beak is only the exterior layer that covers the upper and lower jaw of the bird, though it is often used synonymously with the term bill – the proper word to use to refer to the entirety of the bird’s mouth and nasal structures. The beak is composed of keratin, the same material found in fingernails, antlers, and hooves. Like other keratin-based structures, beaks will continue to grow and can grow up to three inches in a year for some species. While most individuals can maintain their beak length through routine behaviors, sometimes it does take keeper intervention and routine beak trims.
All birds are edentulous, meaning they lack teeth save for the egg tooth they possess as chicks, but even that tooth eventually falls off. This means that chewing their food is not an option. Instead, birds will search for bite-sized morsels or have otherwise adapted the ability to break down their food by means of ripping or tearing. Some scientists hypothesize that the lack of teeth allowed for a shorter incubation time, sparing the parents from the vulnerability and necessity of having to brood the eggs for longer periods of time, while others argue it was a faster and safer means of accessing challenging food.
Looking at the size and shape of a bird’s bill can help with identification, but can also help give you an idea of the sort of diet that individual would enjoy. The deep hook of the eagle’s beak allows for them to rip into the carcass of their prey, while the curve of the ibis’s beak allows for probing, enabling them to dig into holes in the ground to find hiding insects. The pelican’s large flexible bill enables them to fish via a netting technique, while the sharp point of an egret’s bill shows off their inclination to spear their fish. The diversity of beaks goes as far as to specialize within a closely related group of birds. Looking at the difference between the straining technique of our white-faced whistling ducks (who tend to dabble and find grains and insects near the surface) versus diving-duck species such as the smew, with their pointed bills adapted for catching long fish.
Now, the bill is used for more than just picking up food and eating. Defense, feather maintenance (preening), bill sparring, thermoregulation, and vocalizations are just some of the other uses of the bill that don’t correlate to mealtimes. The blue-throated macaws use their bills as a substitute for their hands. Not only do they use their bills to navigate the mesh in their home, but they also tend to grab several treats or small wood blocks and carry it to other areas of the habitat.
Beaks and their uses are incredibly diverse. So, the next time you visit Zoo Atlanta, I challenge you to pay more attention to them. Can you find any birds doing anything other than eating with their beaks? Can you try to guess what kind of diet that bird would have based on how sharp or long a beak might be? It’s a fun little game, and if you happen to find a Bird Team member wandering around, I’m certain any one of us would be happy to tell you if your observations and guesses are correct!
Keeper II, Birds