Graceful Guardians of the Garden: The Enchanting World of Hummingbirds

 Hummingbirds belong to the family Trochilidae, close relatives of the birds known as Swifts. They are small birds capable of hovering in mid air due to the rapid flapping of their wings. They get their name as a result of the audible humming sound made by their beating wings that typically flap at fifty to eighty times per second. They are the only birds capable of flying backwards!             

Although there are twenty-three species of Hummingbirds that are found in North America, the only Illinois resident is the Ruby-throated Hummingbird. Occasionally, the Rufous Hummingbird (Selasphorus rufus), an accidental visitor, is reported by enthusiastic bird watchers.             

The Ruby-throated Hummingbird is the smallest species of bird in the USA, east of the Mississippi. They are the only Hummingbird species that regularly breeds in the Eastern United States and Canada. It is a migratory species that spends most of the winter in Mexico, Central America and the Southern United States. Their nesting habitat is found throughout most of the Eastern North America and the Southern Canadian Prairies. Here in Illinois Ruby-throats usually arrive in early May. The males come first and stake out their feeding territories, followed later by females that breed and raise young for the summer. The males do not partake in the raising of young. Most male Ruby-throated Hummingbirds leave our area in late September to return to their winter range, followed by the females in early October.             

The Ruby-throated Hummingbird bill is approximately 2 cm (4/5 in.) long. Each half is slightly curved. Their bills DO NOT act like a straw for nectaring as previously thought, but are useful for catching small insects. It is actually a bill with 2 parts and a very long tongue inside. The tongue is the primary organ for acquiring nectar and protein. There is a crop, or pouch in the back of the mouth that is useful for temporary storage of both nectar and insects. The tongue is composed of smooth muscle (not skeletal muscle) with embedded bone pieces staggered in the tissues, allowing for a rolling out action. The tongue is split at the tip, with broadened swellings and brushy rudimentary nubs for grabbing insects. With capillary action created by the tongue design, the hummingbird laps nectar at a rate of twelve or more times per second.             

Experts feel that insect feeding is more important to hummingbirds than nectaring.  Hummingbirds insect feed to bulk up before migrating and so females lay good healthy eggs. The females also mix a slurry of nectar and small insects or pollen protein in their crops to feed their young. There is not enough nutritional value in sugar water (nectar).       

The Ruby-throated Hummingbird is known to be important, as a primary pollinator of at least nineteen different species of wildflowers in North Eastern United States and most likely co-evolved with them.  Some of these noted co-evolution flower species are also found here in Illinois and include the following: 

• Wild Columbine ( Aquilegia canadense) 
• New Jersey Tea (Ceanothus spp.) 
• Cardinal Flower (Lobelia cardinalis) 
• Beardtongue or Penstemon (Penstemon spp ) 
• Bergamot or Bee Balm (Monarda spp.) 
• Hardy Hibiscus (Hibiscus Moscheutos)
• Jewel Weed (Impatiens spp.) 
• Rhododendron and Azalea    

While hummingbirds favorite flowers tend to be red, orange or pink in color, eventually they will visit all flower colors including white and blue. One color of flower they avoid is yellow, perhaps because of the co-evolution of yellow flowers with Homopteran insects (bees, wasp and ants).

The most well-known flower that co-evolved with the Ruby-throated Hummingbird is the Cardinal Lobelia.  Lobelia’s long slender flower and the long narrow bill of the Ruby-throated Hummingbird are nearly a perfect match.

Cardinal Lobelia itself is a unique and unusual plant in that its flowers are protandrous,  meaning that the flowers start off as male ‘pollen producers’ and then go through a sex change, becoming female ‘pistilate’ to become pollinated. 

There is a unique relationship between Cardinal Lobelia and its primary pollinator the Ruby-throated Hummingbird. The Rubythroat Hummingbird carries out the pollination process of the cardinal flower inadvertently through the nectaring process. Hovering mid-air, the hummingbird laps nectar with its long tongue from the bottom of a male tubular flower.  While doing so, the Ruby-throats head brushes up against the flower, getting pollen from the stamen stuck to its feathers, which is then inadvertently transferred to a female pistilate flower at a later time when they are eventually visited. 

Cardinal flowers bloom from the bottom up on the floral spike. The newest, most upper flowers tend to be staminate, while the older, lower flowers tend to be pistilate. When the blossom wilts the pollination process has been successfully completed. Note: The wilted blossoms at the bottom of the floral spike.   

The Fall Hummingbird Migration begins by August and September. Hummingbirds are moving south, refueling their bodies in the early morning, traveling midday, and foraging again in the late afternoon to maintain their body weight. 

August brings lots of activity, when there can be as many as 10-20 Ruby-throated hummingbirds at a time, with peak numbers in early September. 

Ruby-throats gather in Florida, Louisiana and along the South Texas coast in September in preparation for the final push to the south, either over the Gulf of Mexico or via an overland route through Mexico. Some Ruby-throats do spend the winter along the U.S. Gulf Coast, from Texas to Florida, and some along the southern Atlantic coastal regions. 

Other species travel south down the Rocky Mountain chain into Mexico and Central America.