The overwintering monarchs do not mate until the increasing temperatures and daylight hours in February trigger the development of their sexual organs. On warm days, the butterflies will leave the trees entirely, seeking out nectar sources with which to replenish their energy reserves, but always returning well before evening to once again cluster in the trees. Since their flight muscles do not function well unless the temperature is above 55 degrees, they rest quietly on the trees, resembling dead leaves, until sunlight warms them enough to fly. At night, they may cluster together in small groups, but as winter approaches, they move on to more permanent overwintering sites.Īfter arriving at their destination, the monarchs cluster in large masses for protection from the elements. The Monarchs feed on flower nectar during the journey, attempting to build up fat reserves that will enable them to survive the winter months. Triggered by the decreasing daylight and angle of the sun, these butterflies delay sexual maturity and begin flying toward their overwintering grounds, in some cases up to 2,000 miles away. These Monarchs live much longer, up to eight months. In late summer and early fall, a special generation of monarchs is born. Monarchs cluster in the eucalyptus trees at the Monarch Grove Sanctuary, as well as in eucalyptus groves at Natural Bridges State Park in Santa Cruz, and at the North Beach Campground in Pismo Beach near San Luis Obispo. The proliferation of Australian eucalyptus trees, first introduced into this country in the 1850s, has also affected traditional overwintering patterns by providing a tree that is not only well-suited to sheltering monarch clusters, but also provides the butterflies with a convenient nectar source since it blooms in winter. The City is attempting to reverse this decline with an aggressive campaign of tree planting, mulching, and trail improvement. However, urbanization, aging of the trees, and environmental stresses have caused a decline of this habitat. Pacific Grove's George Washington Park is also a part of the original overwintering habitat. However, due to the number of monarchs returning to the Sanctuary year after year, the Xerces Society for Invertebrate Conservation ranked it as the 6th most important California overwintering site in a 2016 report. The Pacific Grove Monarch Sanctuary is merely one of approximately 400 overwintering sites along the California coast. In fact, several generations of monarchs have lived and died since last year's butterflies departed. In contrast, migrating monarchs have never been to their destination before. Why is this migration so unique? In many migrating species, such as birds and whales, the same individuals travel the migration route year after year.
A mighty achievement for such a seemingly fragile insect! En route, they may travel as far as 2,000 miles, covering one hundred miles per day, and flying as high as 10,000 feet. Monarchs east of the Rockies spend their winters in the high mountains of central Mexico. Monarchs west of the Rocky Mountains migrate to locations on the central California coast. To survive, monarchs migrate to safe overwintering sites that are neither cold enough to kill it, nor so warm that it wastes precious energy flying too much. It cannot withstand freezing winter temperatures. Where do they come from? The monarch butterfly (Danaus plexippus) is a widespread tropical insect that ranges as far north as Canada. For information, please call 648-5716 ext 20. It can be completed as a self-study at any time during the fall-winter butterfly season. If you are interested in becoming a Monarch Docent, please contact the Pacific Grove Museum of Natural History. Volunteer OpportunitiesThe Museum Monarch Docents provide interpretation at the Sanctuary during the Monarch's overwintering season, from October through February. The Pacific Grove Police Department enforces strict regulations that prohibit the "molestation of butterflies." The fine? $1,000.įor more information on monarch viewing and to access weekly monarch counts, please go to the Pacific Grove Museum of Natural History. Citizens of Pacific Grove voted to create an additional tax to create the Monarch Grove Sanctuary which is cared for by dedicated volunteers. Their migration to Pacific Grove is so unique that Pacific Grove is nicknamed "Butterfly Town, U.S.A." The community has always welcomed the butterflies and advocated for their protection. Every Year Thousands of Monarchs Overwinter in Pacific GroveĪrriving in October, monarch butterflies cluster together on pine, cypress and eucalyptus trees in the Sanctuary.
0 kommentar(er)
