Each spring I anticipate bird migration. Every morning I step out my backdoor and listen for the morning chorus to see who may have arrived overnight. I pay close attention to the pin oaks as they are now in full bloom and this is where the birds are often found.
Why oaks? Temperatures begin to warm initiating the new growth of leaves and the production of flowers. With oaks, the flowers emerge first before the leaves. The male flowers are in the form of a drooping flower called a catkin, and the female is an inconspicuous small reddish flower closer to the tips of the branches. Like many of the trees in our area, oaks are wind pollinated producing a large amount of pollen. The pollen is transported by spring winds, hopefully landing on suitable female oak flower. Typically oaks bloom for about two weeks and this just happens to be when millions of songbirds are migrating through our area. The pollen attracts insects, not for pollination purposes, but to consume the pollen as a high energy food. These insects attract hungry birds, fueling them as they continue their journey north. As the flowers fade new leaves begin to grow and these now tender leaves are food for numerous caterpillars, butterflies, an impressive number of beetles, and other insects adding to the food source for this critical period of birds' annual life cycle.
Oaks' wildlife value does not stop at providing food for migratory birds. They provide a hoard of additional insects for nesting birds too. In Dr. Douglas Tallamy’s book “Bringing Nature Home” he writes about how native oak trees have been shown to support 534 Lepidoptera (butterfly and moth) species and will churn out caterpillars from May – October.
Some nesting birds are caterpillar experts like the Baltimore oriole feeding on countless caterpillars throughout the summer
The wildlife value of an oak continues into the fall when their acorns begin to ripen and fall. Numerous animals utilize this mast crop to increase their fat reserves for the upcoming winter. The list is long from squirrels, raccoons, deer, mice, turkey, ducks, and blue jays to name a few. Other animals will harvest and store them for a winters food supply including chipmunks, flying squirrels and even red-bellied woodpeckers, stashing acorns in holes or crevasses of trees.
Humans too benefit from oaks. They provide shade, oxygen and for centuries they have been a source of hardwood for building ships, homes, furniture and providing heat. Because of their monitory value, oaks have been, and continue to be, harvested from the landscapes. Without replacing them we are slowly losing this very important wildlife tree.
What can be done? This year, Arbor Day is on April 25th and this day for over 140 years has been a tradition to plant trees: http://www.arborday.org/arborday/history.cfm I am encouraging everyone to plant an oak tree on Arbor Day to honor of those who saw the value in restoring trees to the landscape. Everyone can find a species of oak for any soil type in your yard. They will need to be nurtured and protected from deer while they are young, but with luck they will grow and begin to fulfill their role in the ecosystem. In the future others will be able to enjoy the morning chorus of migrating birds from the comfort of their own backyard. And, I am sure the birds and other animals will appreciate it too!
Watershed Stewardship Center