A Community Service of the
American River Natural History Association







A Community Service of the
American River Natural History Association

Anna's Hummingbirds at Effie Yeaw
Thom Parrish
October 15, 2015


There is a cottonwood tree close to the river, past where the observation trail fades into cobbles; the bare forked top branches have long been the favorite perch for a certain male Anna’s Hummingbird.  The sight of this hummer has been a consistent and reliable one that I’ve come to enjoy keeping an eye out for when taking this trail to the river.  


This past Sunday morning I saw him again at his perch chattering away in the wind. The Anna’s Hummingbird has a long breeding season of half of the year, beginning early in the winter and lasting until the end of spring. 

The moment before the drop
It appears that my cottonwood Anna friend is hoping to get the season started early.  I watched him launch from his perch and soar over 100 feet straight up until he was but a speck against the blue, he paused for moment and then dropped like a dart towards the ground.  A few feet from the ground, he arced his trajectory back up, sharply whipping his tail and producing a loud “chirp.”  He repeated his “U” shaped courtship dive several times before resting again atop his cottonwood.

Not far from this male Anna’s cotton wood is a series of tall straight eucalyptus trunks that has come to be known as “the pirate ship.”  This is sometimes a great spot to see multiple hummers at once in high speed action.  Eucalyptus buds are actually one of the Anna’s favorite sources of nectar.   

The presence of migratory hummingbirds has long been a part of the American Parkway’s natural history; however the year-round residency of Anna’s in the Parkway is relatively new.  Historically the breeding and nesting grounds for the Anna’s were limited to the Baja area of Southern California.  The arrival and spread of the Australian eucalyptus tree throughout California as well as widespread planting of garden flowers in the late 19th and early 20th century is largely credited for the Anna’s wide range expansion.  By the mid-20th century Anna’s Hummingbirds became a common sight year round in California’s Central Valley.   The Anna’s is the most common hummingbird found on the west coast and has the northern most range of any hummer, extending up into Canada.  They are the only hummer species in the Central Valley that does not migrate during the cold season.  Their conservation status lists them as a species of least concern, LC. 

 

At Effie Yeaw, the Nature Center’s courtyard is another excellent location to view hummers.  The red fuchsia planted in front of the Assembly Building is one of their favorite flowers to visit. 

The Anna’s Hummingbird, Calypte anna, was named after Princess Anna de Belle Massena, a 19th century French noblewomen for whom famed French naturalist Rene Primevere Lesson collected specimens.  The Anna’s are recognizable by their iridescent emerald green back, a pale gray speckled belly and crimson encrusted gorget.  The term “gorget” comes from a piece of protective armor worn around the neck, used by knights. The red gorget of the male covers the entire neck, face and crown (the only North American hummingbird whose gorget extends over the crown).  The female Anna has a green crown and a smaller red central throat patch.The gorget may not always reflect the brilliant shimmering red, at times it may appear even black.  The throat feathers contain thin film-like layers of “platelets,” set like iridescent tiles against a darker background. Sun light reflects and refracts off these tiles creating color in the manner of sun glinting off a film of oil on water.  A hummingbird uses the bright reflection from their gorget to signal other hummers as well as in attracting a mate. They can subdue the reflection with a turn of their head when they wish to remain inconspicuous.   

 

Their tiny size and delicate jewel-like appearance is in no way a reflection of their behavior; Anna’s are extremely territorial and aggressive towards one another.  They begin to exhibit aggression towards other hummers almost from the moment they take flight and find a source of nectar.  Male and female hummers will claim their own separate territories and will defend them against all comers of either sex.   When dive bombing threats fail they will resort to aerial combat, attacking with beak and claw, sometimes even falling and scuffling on the ground.   That being said, hummers are solitary birds.  The only contact between two adult hummers other than when fighting is during mating; even that may last only a fraction of a second, after which both partners part ways with no further involvement.   Hummingbirds do not form mated pairs. A male may mate with several female hummers during a season and will never see its own offspring.  A female hummingbird will typically make two clutches of two eggs per season.  Females will also mate with more than one partner during the mating season, often resulting in each egg being  fertilized by a different father.  The female will build the nest and care for the young on her own.  The egg incubation period is up to 3 weeks and the time nesting before the babies fledge is also 3 weeks. Their nests are typically made on a sturdy horizontal tree or shrub branch 5 to 20 feet above the ground.   Females build their nests using soft material often gathered from plant fluff and spider webs then reinforced with moss and lichen.  For additional security female hummers have even been known to build their nests near the nest of a hawk.  Hawks typically don’t prey on hummingbirds and they keep away birds like scrub jays that are notorious for nest robbing. 
Hummers are very curious birds, mostly when it comes to determining whether something is a threat, food source, or competition.   Hummingbirds are brave when it comes to predator inspection.  I have seen hummingbirds fly dangerously close in front of cats, almost as if taunting.  Most of the time a hummingbird can evade a predator with ease, but of all animals cats are the number one killer of hummingbirds.  Other animals that make attempts to prey on hummers, especially nesting chicks, include jays and crows.  Because of their small size hummingbirds must also worry about large predatory insects.  Preying mantises have been known to lay in wait near flowers and feeders to ambush unaware hummers.  Dragonflies have also been known to prey on nesting hummingbird babies.   Last Monday just outside the Nature Center I observed what I believe was hummingbird predator inspection.  I was watching the western screech owl perched in front of its tree cavity in the evening just after 6pm.  I was surprised when a hummingbird flew directly in front of the screech and hovered there for a moment. The screech stared back at the hummer with seeming indifference and then the hummingbird darted away.  Every ten minutes or so a hummingbird, not always the same one, would repeat this close hovering inspection of the owl.  Sometimes the hummingbird would perch on a branch and watch the owl and other times even two hummers at once would hover close to investigate.

PART TWO Read more on Anna's Hummingbirds