Ornithologist studies evolution of feeding systems

Photo: Peter Morenus

Margaret Rubega, assistant professor of ecology and evolutionary biology, with bird specimens in the Biology-Physics Building.

Proper etiquette says you should not eat with your mouth open, unless you're a bird, that is.

For some birds, eating with an open mouth is one way nature takes advantage of the laws of physics, and their beaks have evolved to equip them to do precisely that, says Margaret Rubega, a UConn assistant professor of ecology and evolutionary biology who is also the state ornithologist. She conducts research on the evolution of feeding systems in birds and its relationship to the environment to answer the question: Why do birds have so many different kinds of beaks?

"In comparison with other kinds of vertebrates," she says, "birds have such variable mouth parts." Mammals all have jaws, and most have teeth, she notes. Yet there is enormous variation in the size, shape and structure of birds' beaks. Rubega's research focuses on how this variation influences birds' feeding performance, making detailed observations of how birds feed.

Working with shore birds in her lab, she films them feeding at close range with high-speed video equipment - about 250 frames a second. She then reviews the tape at half speed to see which type of beak works best if you give different birds the same food under the same conditions.

"You can't give both a pelican and a duck a fish and expect them to eat it in the same way," Rubega says.

She combines lab research with field investigation. Although keeping birds temporarily in captivity creates an artificial setting, she says, her lab work enables her to control the environment to gather critical data to make direct performance comparisons that are not possible in the field.

Rubega, who came to UConn in 1998, is building on her past research inquiries showing that the red-necked phalarope employs a feeding mechanism that had not previously been associated with any other bird. The phalarope - a bird that spends part of the year out at sea in the Arctic, part in meltwater pools on the tundra, and part on lakes in the western United States - eats tiny invertebrates, using surface tension transport. The bird grabs its prey in the tip of its jaws and water sticks to it, forming a droplet with the prey suspended inside. The droplet is suspended between the bird's upper and lower jaw and when the bird opens its beak, the droplet moves in the direction where it can be as small as possible - in this case, to the back of the bird's beak. The bird pumps its tongue against the roof of its mouth so that the water in the droplet is pushed out and the bird swallows the prey. The entire process happens very quickly.

Rubega hopes to find out how the bird's feeding performance varies in each of its three habitats. She has already learned that oil spills can have a devastating effect on birds' ability to feed using the surface tension mechanism. "If there's oil on their beaks, they can't feed at all," she says, noting that research at the micro level lays the groundwork for examining larger ornithological issues. "Feeding mechanisms translate up. If you want to conserve populations of animals, you have to understand their biology."

She seeks to communicate her excitement about the natural world to her students in an outdoor lab course that is a companion to a lecture class.

"I can't imagine teaching about birds without teaching outside," she says. "You don't need to study the world's most exotic birds to be blown away by how amazing bird biology is."

During a lab last year, the temperature was just 10 degrees outside. Rubega took her students for a campus walk to observe sparrows and talk about thermo-regulation in birds: "The students were complaining (about the cold), yet they were wearing Goretex, Polar Fleece, and down. These birds had just spent the night at 5 below zero."

Rubega explained that birds pick microclimates that help with their metabolism and roost in the most sheltered places they can find.

"In a hard winter," she says, "a lot of birds don't make it," noting that the right beak helps.

Birds have to eat all day long to maintain body temperature, she says, and knowing that they have the right eating utensil - a different beak for each bird - helps them to survive and thrive.

- Elizabeth Omara-Otunnu