Bird Adaptations - Bird Adaptations - BeaksBeaks

Did you ever wonder why Did you ever wonder why there are so many types of there are so many types of bird beaksbird beaks

(scientists call them bills)?(scientists call them bills)?

The most important function of a The most important function of a bird bill is feeding, and it is bird bill is feeding, and it is shaped according to what a bird shaped according to what a bird eats.eats.

Extreme Beaks!Extreme Beaks!A look at some adaptations that help A look at some adaptations that help birds get the food they need.birds get the food they need.

ToucanToucan The toucan's beak The toucan's beak

is adapted to grab is adapted to grab and crush fruit and crush fruit and nuts.and nuts.

It is strong like a It is strong like a nutcracker.nutcracker.

HummingbirdHummingbird

A hummingbird’s long A hummingbird’s long thin beak can get to the thin beak can get to the nectar in flowers.nectar in flowers.

PelicanPelican

The pelican’s beak is The pelican’s beak is adapted to scoop up adapted to scoop up fish to eat. fish to eat.

(Only in cartoons do they use their beaks to transport fish to safety!)

WoodpeckerWoodpecker The woodpecker’s chisel-like The woodpecker’s chisel-like

beak allows it to drill holes in beak allows it to drill holes in trees and eat the insects trees and eat the insects within.within.

Background Background InformationInformation During his five-year trip aboard During his five-year trip aboard

the H.M.S. Beagle, Charles Darwin the H.M.S. Beagle, Charles Darwin discovered that birds called discovered that birds called finches were found on all of the finches were found on all of the Galapagos Islands. Galapagos Islands.

He arrived in the Galapagos in He arrived in the Galapagos in 1835 and found 13 species of 1835 and found 13 species of finch living on different islands. finch living on different islands.

The finches were similar in size and The finches were similar in size and coloration, but had very differently sized coloration, but had very differently sized and shaped beaks. The beaks of these and shaped beaks. The beaks of these finches were adapted to the island where finches were adapted to the island where they lived and the food that they ate. they lived and the food that they ate.

Darwin believed that the process of Darwin believed that the process of evolution took too long for us to observe evolution took too long for us to observe it happening. But the finches of the it happening. But the finches of the Galapagos were an example of evolution Galapagos were an example of evolution taking place and he wrote about them in taking place and he wrote about them in his book called “The Voyage of the his book called “The Voyage of the Beagle”. Beagle”.

Darwin decided that these finches Darwin decided that these finches all used to have bills like other all used to have bills like other finches, but when they came to finches, but when they came to live on the Galapagos and started live on the Galapagos and started eating different things, their beaks eating different things, their beaks changed over thousands of years. changed over thousands of years. This is called divergent evolution. This is called divergent evolution.

Each finch species has evolved according Each finch species has evolved according to its particular food source. For to its particular food source. For instance:instance:

Long beaks are for probing trees and cacti. Long beaks are for probing trees and cacti. Cactus finches have long beaks adapted for Cactus finches have long beaks adapted for reaching into cactus flowers and eating the reaching into cactus flowers and eating the nectar. Warbler and woodpecker finches have nectar. Warbler and woodpecker finches have long beaks for probing into trees to find insects long beaks for probing into trees to find insects and other small animals to eat. and other small animals to eat.

Thick, wide beaks are for crushing hard seeds. Thick, wide beaks are for crushing hard seeds. Ground finches have beaks adapted for Ground finches have beaks adapted for crushing seeds. Medium finches are better crushing seeds. Medium finches are better adapted at eating small seeds than large ones, adapted at eating small seeds than large ones, so they are not likely to be found on islands so they are not likely to be found on islands with variation in seed size and large ground with variation in seed size and large ground finches who are able to eat larger seeds. Wide finches who are able to eat larger seeds. Wide beaks also allow them to take in more food. beaks also allow them to take in more food.

Many of the finches in the Galapagos are not Many of the finches in the Galapagos are not yet distinct species because they are still able yet distinct species because they are still able to reproduce. However, as they are separated to reproduce. However, as they are separated onto different islands, physical barriers prevent onto different islands, physical barriers prevent groups from reproducing. Different species groups from reproducing. Different species may develop when a population is divided and may develop when a population is divided and then the groups evolve in separate ways.then the groups evolve in separate ways.

If the two parts of the population evolve in If the two parts of the population evolve in

different ways and then are able to come pack different ways and then are able to come pack together (if the geographic barrier is together (if the geographic barrier is removed), the two populations may compete removed), the two populations may compete with each other. Or, they may have developed with each other. Or, they may have developed specializations that allow them to no longer specializations that allow them to no longer need the same food type or nesting space, so need the same food type or nesting space, so they may be able to live in the same space they may be able to live in the same space without competition.without competition.