Generalist or Specialist?

Some animals have special adaptations that enable them to take advantage of a special food item that other animals can't get easily. Osprey have feet that are extremely well developed for catching fish, eyes that are adapted for seeing fish underwater when in flight, and a beak perfect for ripping into fish. Osprey are SO well adapted to catching fish, in fact, that they can't catch anything else! Most of them don't even recognize dead fish as food; if they don't catch the fish while it's swimming, they starve.

Bald Eagles catch fish, too, but their feet, eyes and beak aren't so specialized. Eagles can recognize dead fish, road-killed animals, and other carrion as food. And eagles can also catch small live animals on land. Osprey are specialists, and eagles are generalists. Which do you think is more common, and why?

You can sometimes tell a generalist from a specialistby the animal's adaptations. Specialists have "special" parts that help them do one thing very well, but that make other things harder. Because birds use their beaks for so many things, we can often tell if a bird is a generalist or specialist by the shape of its beak. Look at the beak on the female Red-winged Blackbird. This is sort of a basic beak — the kind that can allow the bird to eat many things.

Try This!
Compare the following pairs of beaks, and guess which bird in each pair is more of a generalist and which is more of a specialist.

Insect Eaters
Black Phoebe
Seed Eaters
Nectar Eaters
Sicklebill (hummingbird)
Woodstar (hummingbird)
Fish Eaters

When you're done, check how your answers compare with ours.

Journaling Question
Do you think a generalist or specialist would be more at risk if its environment or habitat changed dramatically? Explain your thinking.

National Science Education Standards

  • Each plant or animal has different structures that serve different functions in growth, survival, reproduction.
  • Living systems at all levels of organization demonstrate the complementary nature of structure and function.
  • All organisms must be able to obtain and use resources, grow, reproduce, and maintain stable internal conditions in a constantly changing external environment.
  • Biological adaptations include changes in structures, behaviors, or physiology that enhance survival and reproductive success in a particular environment.