By Jennifer Nixon, Denver Zoo Bird Keeper
Introducing this week’s Feathered Friend, Una! She is an 11-year-old Chilean flamingo (Phoenicopterus chilensis) that was hatched and hand raised here at Denver Zoo in 2003. Una is now a breeding member of our flock and has raised three chicks, one each in 2011, 2012 and 2013 and has proven to be a very calm and good mother. Her youngest chick is named Elvis and he is still in all grey feathers. There are six species of flamingo and Denver Zoo is home to two species: Chilean and American. Today, April 18, is their first full day out for the summer season. They have been in their winter holding area near the bald eagles, but now that the weather is warming up they are back outside for the summer.
You can tell the Chilean flamingos apart from the American because the Chileans are a softer/lighter pink. All flamingos get their coloring from the food they eat. They eat food that contains carotenoids such as canthaxanthin, which colors the feathers and astaxanthin, which colors the skin and legs. In the wild they would eat invertebrates, mollusks, insects, crustaceans, algae and other plant material. Here at the Zoo, Una eats a formulated soaked pellet for flamingos. She also loves to eat krill and silversides for a treat. Flamingos can’t make the color on their own so they will fade to grey or white if they don’t eat foods containing the red pigments. The chicks are born grey or white and get the pink color as they age. Una is one of 48 Chilean flamingos here at the Denver Zoo. With the 22 American flamingos, there are now a total of 70 flamingos total with both species out enjoying the Colorado sunshine.
Una has a very special way of eating. She filters her food like some whales. Flamingos hold their head upside down in water and suck in water and food with their piston-like tongue that fits inside the lower beak. The tongue has barbs facing the throat that pulls the food in and the water is pushed out through the lamellae (rows of keratinous plates covered in tiny hairs called cilia) similar to some whales. Sometimes you will see her stamping her feet in the water to flush up more food from the bottom.
When you look at Una you might think that she has a backward facing knee. This is one of the interesting facts about bird anatomy. What looks like a knee to us is actually the equivalent to her ankle joint. Her knee joint is up high in her feathers and hidden from view. Her upper leg (tibio-tarsus) is the same as the human lower leg. Her lower leg is what we would call the upper foot bones also called the tarsometatarsus in birds. There is also minimal muscle in bird legs below the knee. Instead of muscle they mostly have tendons in their lower legs.
You can visit Una at her summer home on the Flamingo Ponds near Lorikeet Adventure. You can tell her apart from the other flamingos by her leg band, Green 40 on her left leg. She is also the shortest adult Chilean flamingo. Celebrate the warming spring weather and come see them out in their summer home. We have our fingers crossed for some nesting on the island and new arrivals this summer!