(1) The next time you pucker up under the mistletoe for that holiday kiss, remember that the plant also provides food, cover and nesting sites for birds, butterflies and mammals in the United States.
(2) There are more than 1,300 species of mistletoe found all over the world. And more than 20 species are listed as endangered, according to United States Geological Service (USGS) scientists.
(3) Two kinds of mistletoes are native to the United States: the American mistletoe (the one commonly associated with our kissing customs) and the dwarf mistletoe. American mistletoe is found from New Jersey to Florida and west through Texas. The dwarf mistletoe, much smaller than its kissing cousin, is found from central Canada and southeastern Alaska to Honduras and Hispaniola, but most species are found in western United States and Mexico.
(4) Mistletoes are rather strange plants that grow on the branches of trees and shrubs. The American mistletoe’s scientific name, Phoradendron, means “thief of the tree” in Greek. Once its seed lands on a host tree, the mistletoe sends out roots that penetrate the tree and start stealing some the host tree’s nutrients and minerals. Eventually, mistletoes grow into thick masses of branching, misshapen stems, giving rise to a popular name of witches' brooms, or the Navajo name of "basket on high."
(5) The plant's common name -- mistletoe -- comes from early observations that mistletoe would often appear in places where birds had left their droppings. "Mistel" is the Anglo-Saxon word for "dung," and "tan" is the word for "twig." So, mistletoe means "dung-on-a-twig." Talk about taking the romance out of that next kiss under the mistletoe!
(6) Even though bird droppings do not generate mistletoe plants, birds are an important part of mistletoe life. Birds find mistletoe a great place for nesting and many birds, including grouse, mourning doves, bluebirds, evening grosbeaks, robins and pigeons eat mistletoe berries.
(7) This year, USGS is beginning a study on mistletoes that live on acacia and mesquite trees in the desert. Todd Esque, a USGS researcher, said that his goal is to understand the distribution of the host trees in relation to mistletoe patterns and bird behavior. "We know the relationship is mutually beneficial for both species," said Esque.
(8) According to butterfly expert and Colorado State University professor Paul Opler, three kinds of butterflies in the United States are entirely dependent on mistletoes for their survival: the great purple hairstreak, the thicket haristreak, and the Johnson’s hairstreak. The great purple hairstreak, says Opler, is the only butterfly in the United States that feeds on American mistletoe, the Christmas mistletoe. This beautiful butterfly lays its eggs on the mistletoe, where the resulting caterpillars thrive on a mistletoe diet. The caterpillars of the other two butterflies feed on dwarf mistletoes.
(9) Mistletoe is also important nectar and pollen plant for honeybees and other native bees, says Erik Erikson, a bee researcher at the USDA Bee Research Lab. Mistletoe flowers, says Erikson, often provides the first pollen available in the spring for the hungry bees. "We look upon it as an important starter food source for the bees," said Erikson.
(10) While mistletoe is poisonous to people, many mammals eat the berries and leaves, especially in the autumn and winter when other foods are hard to come by. Researchers have found that animals such as elk, cattle and deer eat mistletoe during winter when fresh foliage is rare. Other mammals that eat mistletoe include squirrels, chipmunks, and even porcupines, some of which are very fond of the plant. A variety of squirrels, including red squirrels, Abert squirrels and flying squirrels often use witches brooms for cover and nesting sites.
(11) But not everyone likes mistletoe. Many commercial foresters consider the dwarf mistletoe as a disease that reduces the growth rates of important conifer species, such as the ponderosa pine.
(12) So the next time you’re waiting for that holiday smooch, remember that some animals think of mistletoe as only a source of food and shelter.