Hummingbird Homecoming

 

Hummingbird feeders are busy during spring migration!

Early spring marks the beginning of several natural events, and one of the most welcome is the return of hummingbirds to central Texas.  While the number of hummingbirds migrating north in the spring is only about half of those migrating north in the fall (as the fall migration includes all immature birds that hatched in the summer as well as surviving adults), spring migration for these tiny birds is nonetheless an incredible feat.

Most scientists believe that the lengthening of daylight hours triggers the journey north, and evidence exists that hummingbirds follow a different route in the spring versus the fall.  While they follow the Texas coast south in the fall, presumably to avoid hurricanes in the Gulf of Mexico, in the spring they travel north hundreds of miles non-stop directly over the gulf’s calmer waters. 

Hummingbird feeders, filled with a clear solution (no red dye) of one-part white table sugar to four-parts water, should be placed out in early March.  Records show that the migrating hummers start arriving in our area at that time.  While these migrants can include more northern species that are just passing through, they mainly include the arrival of species that breed in our area, such as the Black-chinned Hummingbird (Archilochus alexandri) and the Ruby-throated Hummingbird (Archilochus colubris).

Black-chinned Hummingbird, male

Measuring a mere three and one-half inches long with a three and three-quarter-inch wing span, the Black-chinned hummingbird weighs only three to three and one-half grams, which is about equivalent to the weight of a dime plus a dollar bill. The male is dull metallic green above, gray below, black on the chin and upper throat, with an iridescent violet lower throat known as a gorget (pronounced gore-jet). The female lacks the characteristic coloring on the chin, upper throat, and lower throat.  Ruby-throated hummingbirds are also only about three and one-half inches long with the adult male having a black upper chin and ruby-red gorget, and they are a more eastern species with Austin being the westernmost border of their range. 

Ruby-throated Hummingbird, male

Like all hummingbirds, nectar serves as a main food source, fueling the tiny bird’s extreme metabolism.  These hummingbirds feed on several species of blooming plants, most notably native penstemons, agaves, salvias, sages, and honeysuckles.  While artificial feeders supplement their diet, they also prey on insects and spiders, particularly during nesting season, which gives them the dietary fat and protein necessary to breed.

The hummingbird’s unique skeletal structure allows them to fly forwards, backwards, sideways, and even on their backs!  This requires a wingbeat frequency of about 50 beats per second, and massive muscles that make up a third of their tiny body weight.  While the males perform an elaborate flight display during courtship, no pair bond is formed between the males and females.  Females build the tiny nest (out of spider webs, mosses, and various plant fibers), incubate the eggs, and raise the young, while the males are feeding and off chasing other females.  This is unusual among birds as a whole, since this class of animals exhibits the greatest amount of monogamy among vertebrates (animals with a backbone or spinal column).

Rufous Hummingbird. male

While most hummingbird species have moved out of our area by late October, be sure to leave a feeder out for stragglers and northern species that may spend the winter in your yard.  The most common overwintering species is the Rufous Hummingbird (Selasphorus rufus), but you can sometimes get a wayward winter visitor such as a Broad-billed Hummingbird (Cynanthus latirostris), a rare species in our area that arrived on our back porch feeder on September 11, 2021 and is still with us!

Broad-billed Hummingbird, male

Magical Migrant

Typical hummingbirds in our area include Black-chinned and Ruby-throated.

Known for their diminutive size, long thin bills, and amazing agility in flight, hummingbirds are in the order Apodiformes, meaning ‘unfooted birds’, as they have characteristically tiny feet and are unable to walk on the ground. They are in the avian family Trochilidae, often described as a group of more than 300 species of small, often brilliantly colored hummingbirds.  

While we frequently have Black-chinned and Ruby-throated Hummingbirds here during the warmer months, we also generally expect to have a Rufous Hummingbird spend the winter in our yard.  As such, we are used to keeping a feeder up all year round, but imagine our surprise when a male Broad-billed Hummingbird (Cynanthus latirostris) showed up at our feeder on September 11th!

The male Broad-billed Hummingbird at our back porch feeder.

Most of the Broad-bill’s range lies in Mexico, but it normally spends the breeding season in the mountains of extreme southeast Arizona and southwest New Mexico, where it prefers semi-shaded stream canyons and riparian areas with sycamores, cottonwoods, and willows.  They are short-distance migrants, and their winter range is typically entirely within Mexico.  Very few remain in the U.S. in winter, usually very near the Mexican Border, so to find one in Central Texas is a rare treat!

The brilliantly beautiful male Broad-billed Hummingbird!

Broad-bills are a rather small hummingbird with a long, straight bill and a center tail notch.  The male’s vivid red bill, rich emerald green body, and glittering sapphire blue throat (also called a gorget) is unmistakable!  Females are golden-green above and pale gray below, with a white line behind the eye.  When courting the female, the male hovers about a foot from the female and makes a flight display that is likened to a precise swing of a hypnotist’s pocket watch.  

The male Broad-billed Hummingbird perches in our Escarpment Black Cherry
in between trips to the feeder.

The female typically chooses a nest site about three feet off the ground in a downward-hanging tree branch or shrub. They weave 1-inch tall, 0.75-inch wide cups of bark strips, grasses, and leaves held together with spider silk that appear similar to clumps of vegetation deposited in branches during periods of high water, offering them a degree of natural camouflage.  After laying a clutch of 2 to 3 white eggs, the female incubates them and raises the young alone.

In the warmer months these hummers visit flower gardens but rely on sugar water feeders in winter when blooms are not readily available.  They consume more than 1.5 times their body weight in nectar each day, and often travel long distances between nectar sources.  They feed most often in the morning and late afternoon, which is when flowers produce the most nectar. Broad-bills can also capture tiny insects by gleaning them from plants and flycatching.  As small as they are, they often join others birds in mobbing owls perched during the day, to reinforce to young ones what predators look like or to help drive potential predators away.

There are 5 or 6 similar subspecies of Broad-bills in Mexico, but only the subspecies magicus is known to occur in the U.S.  Climate change has already begun to reshape the range of this hummer, although scientists believe that the vulnerability of this species will remain fairly stable overall.  It has been estimated that for its current range, about 16% has already been lost in the mountains of Mexico, 85% is maintained, and 35% is gained by expanding further north into Arizona, New Mexico, and West Texas.  Whatever the outcome, we welcome this magical migrant, and hope that he spends the entire winter with us!