The Feathered Bees’ Spring Arrival

RTHU in flight. PC: Michael Janke.

The smell of spring permeates the air as the grass begins to poke through the sodden dirt and buds emerge from the tips of the trees.  Concurrent with the change of seasons is another great event – hummingbird spring migration!  While there are more than 330 different species of hummingbirds (Trochilidae), only around 12 to 15 species routinely nest in the U.S.  For us resident Bay Staters’ we can expect to see even less!  The Ruby-Throated Hummingbird (Archilochus colubris; RTHU) is the only breeding hummingbird in eastern North America.

Twice a year, these tiny powerhouses undergo an 805 km migratory route—some individuals coming from as far away as the Pacific slope of Costa Rica and flying up into Central Alberta, Canada.  Despite their small size (females averaging 3.5 grams and males averaging 3.0 grams), most fly nonstop across the Gulf of Mexico during spring migration.  In Massachusetts, you can expect to see these sparkling gems beginning in mid-April.  In fact, the first sighting was just reported on eBird—an online database of real-time bird observations—in East Falmouth, MA on April 27th.

Before embarking on their migratory routes, RTHU will gain about 25-40% of their body weight, fattening up on nectar and insect.  Once they have arrived in North America, RTHU get right to work replenishing their depleted reserves.  While hummingbirds are birds, they feed similarly to insects and have appropriately been dubbed “feathered bees” by the National Audubon Society.  Like insect pollinators, hummingbirds fly from flower to flower in search for nectar.  As a hummingbird dips its bill into flowers, pollen grains stick to their feathers and bill which get carried and distributed to the next flower.  It is estimated that nearly 8,000 plant species throughout the Americas rely on hummingbirds as their primary pollinator.

Female RTHU resting on flower. PC: Nick Dorian.

Hummingbirds and plants represent a classic example of a plant-pollinator relationship and demonstrate coevolution—the phenomena of intimately linked organisms influencing each other’s evolution.  Hummingbird-dependent plants have evolved several “pro-bird” traits including sucrose-rich nectar, brightly colored, unscented flowers (smell is important for insects to find flowers, while birds rely on vision), and tubular flowers that allow easy access for hummingbirds.  Like other pollinators, when native plants thrive, so do hummingbirds.  To sustain a heightened metabolism (their hearts beat as fast as 1,260 beats per minute after all), hummingbirds eat once every 10 – 15 minutes and visit between 1,000– 2,000 flowers per day!

Unfortunately, the preferred habitats of RTHU are changing along their migratory routes due to habitat conversion and climate change.  There has been an increase in the concern about the conservation of pollinators in urban environments.  A known way to mitigate the impact of urbanization is through native plants gardens which provide both habitat and resources for pollinators.  Such efforts can also encompass native plants with specialized hummingbird-pollinated flowers in urban landscaping.  In the northeast, planting red cardinal flower (Lobelia cardinalis) or trumpet honeysuckle (Lonicera sempervirens) in your garden may contribute to community restoration and ecosystem functioning by attracting RTHU—and who wouldn’t want these cuties flying around their yard?

Female RTHU drinking from L. cardinalis. PC: Max McCarthy.

Do you want to start your own pollinator garden this year, but don’t know what plants to get? Come to our Grab-n-Grow Native Plant sale next month to stock up on all thing native plants!  More information can be found at: https://sites.tufts.edu/pollinators/cultivate/native-plant-sale/.

Leave a Reply

Your email address will not be published. Required fields are marked *