Hummingbirds – miracles of evolution

Of all birds hummingbirds are one of the most fun to watch.  They are fast, colorful, and tiny, the smallest ones roughly the same size as a large moth or butterfly.  They are probably best known for their maneuverability.

Anna’s Hummingbird (Calypte anna) coming in for a landing. Note the small tail, the curve of the body, and the large wing muscles.

These birds are compact and extremely well muscled.  Their tails are short and flexible, notice how the tail of the Anna’s Hummingbird in the above photo is curved to the side and folded to cup the air to assist in guiding the bird in to its landing spot.  Their wings are short with thick muscles covering the limbs and have a range of motion far greater than that of other birds.

The name Hummingbird comes from the noise of their wings beating at 25 beats per second, about 1500 beats per minute. This high wing-beat and the extraordinary wing flexibility allows hummingbirds to hover far more effectively and energy efficiently than any other bird.

To hover they flap their wings in a figure-8 pattern, generating lift on both the down and upstroke.  Approximately 75% of the life of generated on the down-stroke with the remainder on the up-stroke.  The University of Texas has some nice graphs and charts providing more detailed information on how this works.

Anna’s Hummingbird hovering in front of Tobacco Tree (Nicotiana glauca) flowers

In to achieve this maneuverability hummingbirds give up the ability to glide.  In effect they have no low energy flight, they are always running at near full speed.  A 170 pound person would need to eat (and metabolize) 130 pounds of bread a day to keep up with energy output of a hummingbird.  Their energy output is so great that they enter torpor at night, a sort of hibernation.  If they did not do this the hummingbird would starve to death during the night.

Hummingbird flight characteristics are very nearly a blend of bird and insect methods of achieving lift.

Hummingbirds are generally extremely colorful, especially the males.  Like many birds this color is not pigment generated, but is the result of highly specialized feathers light refracting feathers.  Think of oil on water, that rainbow sheen that you see when light reflects from it.  Birds use the same technique, but in a far more specialized way.  Rather than an undifferentiated rainbow of colors the micro-structure of the feathers refracts only specific colors.  The natural color of the feathers is a dark brown, almost black.

Anna’s Hummingbird (Calypte anna) perched on a non-native Tobacco Tree (Nicotiana glauca)

I know I’ve used this photo before, but it illustrates the refraction vs pigment issue well.  The bold purple-pink behind the bird’s eyes is the color we associate with the male Anna’s Hummingbird’s head and gorget (the throat portion).  The dark, almost black, feathers are at the wrong angle to reflect the light and show the natural dark color of their pigment.

The tree in these photos is a Tobacco Tree (Nicotiana glauca), not native to North America, but native to South America, a place where there is a stunning variety of hummingbirds.  This tree and hummingbirds have a long relationship and have mutually evolved to reinforce that relationship.  Hummingbirds and may other birds and insects (and not a few mammals and reptiles as it turns out) drink nectar from flowers.  Not everyone who drinks the nectar will pollinate the plant, thus special relationships evolve.  Plants with long tube-like flowers (penstemon, humming-bird sage, tobacco, monkey flowers, heliconia, etc) are specialized to provide nectar for animals with long tongues that can reach the nectar.

Hummingbird tongue

Hummingbirds not only have long, narrow beaks, they have long, feathery tongues with which to lap up nectar hidden deep inside the tube-like flowers.  As they drink the plant deposits pollen on the beak and sometimes the bird’s head (two photos up you can see the pollen discoloring the hummingbird’s beak).  The next flower the bird visits gets a little pollen from the previous flower and the plant is happy.

A quick look at the shape and color of flowers will often give you a good sense of what type of animal the plant relies on for pollination.

Hummingbird catching insects under a Coast Live Oak

Hummingbirds need protein as well.  Some, such as the Anna’s Hummingbird, catch insects in flight, many others raid spiderwebs for insects.  Here in North America this is a relatively safe prospect, but in parts of South America there are spiders that will happily catch and eat a hummingbird and spin webs more than strong enough to trap the birds.

Hummingbirds have such a need for vast quantities of high energy foods that they are often extremely territorial, engaging in vicious fights and high speed chases.  Like most animals they would rather warn opponents off than waste energy fighting them.  Different species have various methods of letting others know how tough they are.

Anna’s Hummingbird staking out its territory

The little fellow above is marking out territory by fluffing out his head feathers.

One of the most amazing things about hummingbirds to me is that they migrate long distance, some species crossing the Gulf of Mexico in one long flight with no food.  At the shortest distance this is a flight of 480 miles, many birds fly closer to 600 miles to make this open water trip.  For a bird that only weights several ounces, cannot glide, and needs to eat constantly this is a truly remarkable voyage.

On a final note, hummingbirds are far more intelligent than most people realize.  Their memories are phenomenal, allowing them to keep track of individual flowers within their territories and when they were last visited for nectar.  They have the largest brain-to-body size of any bird.

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A Brief Stopover in the Santa Monica Mountains

I am back on the West Coast of the US for a few weeks before I fly off into tomorrow sometime in November.  The specific part of the west coast I am in is the Santa Monica Mountains, a rugged stretch of steep sided hills perched over the Pacific Ocean covered with blanket of dense chaparral.

Evening sunbeams in Topanga

The precipitous, heavily weathered mountain slopes are eroding from ancient sea-floor uplifted and broken by geologic stresses, frequently manifesting in the form of earthquakes.  The region is dry, though fog is common and periodic rainstorms can quickly drench the area, causing local flooding and landslides.  The dusty ground is colored a dull orange/tan with angular, flat, broken pebbles peeling out of shallow, soft bedrock with occasional anemonite and bivalve fossils.  Under the twelve foot chaparral canopy the gritty soil is overlain by several inches of slowly decomposing leaf-litter and twigs, loose in some places, held together by dense mycelial mats in other places, particularly under the scrub and live oaks.

Infrequent damp, cool places are home to massive coastal live oak (Quercus agrifolia) and California sycamore (Platanus racemosa) while a bewildering variety of woody shrubs make up the body of the chaparral cloaking the rest of the mountains.  Here and there small meadows, potreros in the southern California vernacular, and wind-blasted rock outcrops break up the gray/green vegetation.

Lemonade Berry (Rhus integrifolia) flower buds

Chamise, Toyon, Scrub Oak, Lemonade Berry, Ceanothus, Yucca, and various sages make up much of the more common large shrubs with Black Walnut, Elderberry, Coastal Live Oak, and California Sycamore making up the primary larger trees.  The softer vegetative plants of the understory tend be short-lived, only appearing to bloom and set seed after the rain.

The thick, leathery leaves of the Lemonade Berry (Rhus integrifolia) in the image above are fairly typical of chaparral plants in that they are mostly evergreen and have evolved to husband moisture.  Some plants steal their nutrients from other plants, Dodder (Cuscuta californica) is common in the chaparral, some years blanketing their hosts with yellow-orange leafless vines sporting nearly invisible flowers.

Dodder (Cuscuta californica) on Lemonade Berry. Dodder is most active after rains.

For such a dry region the diversity of both plant and animal life is astounding.  The most obvious animal life during the day are the birds.  Birds of all sizes everywhere, year round.  Little tiny acrobatic birds such as the Bushtit traveling in small noisy flocks.

Bushtit (Psaltriparus minimus) on scrub oak

Large birds of prey soaring overhead in search of thermals or their next meal.

Red-Tailed Hawk (Buteo jamaicensis) riding the wind

Meadowlarks, finches, wrens, thrashers, scrub jays, woodpeckers, hummingbirds quail, and a host of other birds flit about within earshot, if not within eyesight.

Western Meadowlark (Sturnella neglecta) atop a Toyon (Heteromeles arbutifolia) shrub, a popular food bush for many birds. Toyon is also known as Hollywood, the plant Hollywood owes its name to.

Anna’s Hummingbird (Calypte anna) perched on a non-native Tobacco Tree (Nicotiana glauca)

Mammals abound as well.  Small rabbits scatter like frogs in a pond in the evenings, and in the mornings I find fresh coyote, fox, bobcat, skunk, raccoon, deer, and mountain lion tracks on the unused dirt roads.  In the potreros badgers are not uncommon, large woodrat piles abound, bats fly through the canyons in the evening, and ground squirrels are everywhere.  Sometimes, if you have a quiet foot, a lot of patience, and good deal of luck you sneak up on these animals.  A few years back I was out here and found a coyote sleeping in the sunlight.

Coyote (canis latrans) sleeping in the sunlight

This being a dry area there are numerous lizards and snakes, mostly hidden from sight, and insects of all sorts.

I prefer wet places, places that stay green, but I do appreciate and enjoy the diversity of life here in the steep chaparral.  It is strange to be here between damp New England and my next home in Borneo where I will receive 3-4 meters of rain a year.

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Some of these photos are taken with a Nikon D80, some with a Nikon D90, and several with a Nikon D600.  I am still learning the latter camera, but if any of you out there are debating buying the D600, I can honestly say I recommend it.  The Meadowlark and Hummingbird images were taken with the D600 and are cropped from much larger images.