We all remember those lectures we got about the birds and the bees, but chances are an important part of that lecture was left out. Collectively, this diverse group of wildlife including insects, birds, bees and bats, are known as pollinators. They contribute to a healthy ecosystem by transporting pollen from one plant to another to facilitate fertilization. In fact, bees are responsible for pollinating more flowers than any creature on earth. We see pollinators everywhere during the summer months, but where do they go during the fall and winter, and what enables them to produce fruit and seed when the weather warms up again?
Off-Season Activities of Pollinators
Many bees and other insects die, leaving their eggs or pupae to lie dormant. These are tucked away in sheltered places-behind bark, under dead leaves, buried in soil-where they are protected from frost until the following spring, when life can continue. Others survive as adults, hidden in similarly sheltered spots.
In contrast, some pollinator species undertake astonishing journeys to avoid unfavorable weather conditions. Monarch butterflies and rufous hummingbirds fly thousands of miles across North America. Long-nosed bats make shorter, but no less rigorous migrations over hundreds of miles of desert. The monarch butterfly has arguably the most amazing migration of any creature. During the summer, monarchs may be found as far north as central Canada, but as summer fades millions of butterflies head south towards a few small patches of forest in the mountains of Michoacan, Mexico. Some fly more than 3,000 miles, taking over two months to complete the journey. There are also many smaller overwintering sites on the coast of California, but the Mexican sites are the winter home for more than 99 percent of the population. Here they gather to overwinter in the cool, stable conditions provided by Mexican forests.
The journey north next spring is undertaken in two generations. As they fly north from Mexico, the butterflies lay eggs on flowering milkweed. They may lay eggs for a thousand miles before dying. The generation born from these eggs will fly further north again as the milkweed flowers. The monarchs that reach Canada may be two generations removed from those that overwintered in Mexico. Some hummingbirds undertake an equally impressive trek. Along the West Coast, the rufous hummingbird breeds as far north as Alaska, and the ruby-throated hummingbird breeds across central and eastern parts of the continent into southern Canada. Both species overwinter in Mexico. To reach their winter territory, some birds travel well over 2,000 miles! Along the migration route, they stop at flower patches to lap up carbohydrate-laden nectar and feast on fat and protein-rich insects that together provide energy for the exhausting flight. Hummingbirds are known to live for over a decade. To have completed this annual migration so many times is a pretty astonishing achievement for a bird that weighs less than a nickel!
Preparing For Migration
The lesser long-nosed bat over-winters in Mexican caves and migrates several hundred miles north into southern Arizona and New Mexico as warmer temperatures and longer days allow desert flowers to bloom. Migrating pollinators need rest stops along the way. Rufous hummingbirds, for example, cannot complete the entire journey on one tank of nectar and insects. Monarch butterflies need milkweed on which to lay their eggs to ensure the next generation of migrants. Sustaining pollinator populations means ensuring that plant resources are available along their route. Patches of nectar-rich habitat act as stepping-stones that the pollinators can move between, together forming nectar corridors across landscapes altered by agriculture and development.
Hummingbirds are not at all shy, and can be viewed at close range when they visit feeders placed near the house or on windows. Fresh sugar water in feeders will supplement their regular diet of nectar and insects and help ensure that they will be regular visitors to your yard all summer.
The shy, solitary bees, like orchard bees, can help fill the gap in pollination left by the declining American honeybee. These bees are harmless and have solitary nests rather than hives. A nest of small, hollow tubes in which they can raise their larva helps keep them in your yard.
Our Produce Depends On Pollinators
Pollinators are responsible not only for the continued existence of healthy plant communities - and therefore the ecosystem upon which we rely - but their pollination service also provides us with much of the produce we humans need and enjoy. Unfortunately, pollinators as a group are on the decline worldwide. Habitat destruction through sprawl, use of chemical pesticides, spread of invasive non-native plants and animals, and sometimes just plain ignorance about the important role pollinators play are some of the causes for this decline.
Help Pollinators By Providing Their Habitat
Experts at the National Wildlife Federation (NWF) say the most important things you can do now in your yard to accommodate pollinators, or attract pollinators next spring are: plant native plant species as a source of nectar for bees, butterflies and hummingbirds; plant host plants for butterfly caterpillars; replace lawn areas with prairie or meadow nesting sites; and discontinue the use of chemicals and fertilizers in your yard.
To learn more about specific pollinators in your area, check out the Wildlife Finder at NWF's web site, including info on how to create wildlife-friendly landscaping through NWF's Backyard Wildlife Habitat program. When your habitat meets all the criteria for sustaining wildlife, it can be certified by NWF as an official Backyard Wildlife Habitat site.
Matthew Shepherd of the Xerces Society contributed to this article as part of the efforts of the North American Pollinator Protection Campaign.
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