Hummingbird
When I was growing up in London, birdwatching was one of my hobbies. A very amateur ornithologist, my principal concern was to tick off more and more birds on my ‘life list’, identifying the species listed in my Field Guide to the Birds of Britain and Europe. It appealed to me: bird watching combined the challenge of completing a collection, the opportunity to go off to new places, and a solitary pursuit! Inevitably, the list of birds seen grew, despite the fact that trips because less frequently as I began my secondary education. Then in no time at all I was married, had children, and time for ornithology dropped down and down. I kept my copy of Peterson’s Guide, however. After all, it contained my checklist.
Then I moved to Australia. That was a shock, not the move, but the discovery there was a whole world of new birds, and some that might have seemed exotic in the past were now everyday. There were cockatoos, parrots of all shapes and sizes, and even that amazing creature, the black swan. I bought another book to help me identify birds in Adelaide, then in Melbourne, and wherever I went on holiday. However, I didn’t tick new sightings off on my list. I didn’t even start an Australian checklist. Instead I became fascinated by some birds.
Now I was more interested in just watching. There were Splendid Blue Wrens in the garden, and I loved them, as they dashed in close by the living room window. As quickly as they appeared, they would disappear again. Brief, slightly tantalising visits. At the other extreme, there was a pair of Wedge-Tailed Eagles that would circle about our house when the Sheldrakes moved outside Melbourne. From time to time I’d get out my binocular, and watch them lazily circling above the valley, waiting for that moment when one would plunge towards the ground, incredibly quickly, to pick up an unsuspecting rabbit for lunch.
Then I moved to the United States. By this stage in my life, checklists and even an attempt to seek out various birds was lost. Too late. However, early on, I discovered there were humming birds where we lived, if only there for the warmer months. The Ruby-Throated Hummingbird generally spends the winter in Central America, Mexico, and Florida, and migrates to Canada and other parts of Eastern North America for the summer, and to breed. It is the most common hummingbird variety in eastern North America, having population estimates of about 35 million. Within a year of arriving, I had bought a hummingbird feeder, a plastic dish with a bright red cover, which I suspended from one of the beams in our upstairs pergola. The cover was decorated with flower shapes, and in the centre of each flower was a hole. My task was to fill the dish with sugar water (in a 1:3 ratio), put the cover lid on the bowl, suspend it, and wait.
I’m not sure if it was the colour or the faint smell of that sweetened water, but before long the hummingbirds arrived. The door to the pergola from the living room was mainly made of glass, and I could watch my visitors. Eventually I became bolder, and would sit outside, away from the feeder and watch. The next year I took my camera out with me and started photographing hummingbirds both in flight and on the feeder. I put up a second feeder.
I guess I was a naïve observer, at least to begin with. I knew those Ruby-Throated Hummingbirds were the only variety I would be seeing in North Carolina. The hummingbird is native to the Americas, and there are more than 350 varieties that have been described. However, the great majority of these species lived south of where I was based, and especially in the central and the northern parts of South America. Not that I cared about such matters. I loved the ones in my garden.
They are small birds. The body is about 8 cms long, and the wingspan is around 10 cms. The sexes differ in feather coloration, with males having a distinct brilliance together with the ornamentation of their head, neck, wing, and breast feathers. The most typical feather ornament in males is what is called a gorget: below the beak this is a bib-like iridescent neck-feather patch that changes colour and brilliance depending on your viewing angle. As I am sure you have already realised, this isn’t to entrance birdwatchers, but to attract females and warn male competitors away from one bird’s territory
However, I soon discovered I was naïve in another way. Hummingbirds are very territorial. As with many bird species, the colourful males are distinctive, and it didn’t take me long to realise there were two males that would come to my feeder. One of the two considered my pergola and its feeders as ‘his’, and he was extremely aggressive. He, and ‘his’ females, would rest in one of the trees across the lawn, close to the small pond at the bottom of our garden. I don’t know where the other male hid, but he would sneak over to the pergola and take a couple of sips of sugared water if he got the chance to do so, before the other male appeared and chased him off. Sometimes he couldn’t even get to the feeder.
Ruby-throated hummingbirds are described as solitary. Adults are not social, other than during courtship, which is described as “lasting a few minutes”. Then the males buzz off and the female is left to care for her offspring. Both males and females of any age are aggressive towards any competitors. They defend their feeding territory, attacking and chasing other hummingbirds and any other threats that dare to enter.
As part of their spring migration, birds fly from Mexico across the Gulf, arriving first in Florida and Louisiana. Some of these then travel further north, including to North Carolina. Their migration is impressive, as it is an 800 km non-stop flight over water. The birds can double their body mass in preparation for their Gulf crossing, using up the whole of their fat reserves during the 20-hour non-stop crossing, given food and water are unavailable.
Wikipedia reveals “Hummingbirds have one of the highest metabolic rates of any animal, with heart rates up to 1260 beats per minute, breathing rate of about 250 breaths per minute even at rest, and oxygen consumption of about 4 ml oxygen/g/hour at rest. During flight, hummingbird oxygen consumption per gram of muscle tissue is approximately 10 times higher than that seen for elite human athletes. (all this amazing data comes from research by J L Hargrove, reported in the 2005 volume of Nutrition Journal (issue 36)).
They feed frequently while active during the day. When temperatures drop, particularly on cold nights, they may conserve energy by entering a state rather like suspended animation. Given the uncertainty of weather, I had put up a couple of nesting boxes for the hummingbirds, but I soon realised that only one was used in my garden!
Perhaps I should have explained about the name ‘hummingbird’. These tiny birds aren’t silent fliers. Their name derives from the humming sound their wingbeats make while flying and hovering to feed or chasing other hummingbirds. Apparently, humming serves a number of purposes, in particular alerting other birds of the arrival of a fellow forager, potential mate, or intruder. The noise is made by the rapid wingbeats (around 50 beats per second), and they sound a bit like a child’s musical toy. The sound they make is distinctive, quite unlike the whine of a mosquito, let alone the buzz of a bee. Disconcertingly, there is another sound you hear when an intruder appears: one bird will ‘buzz’ another, and the wings may actually touch, producing a snap. I have to assume that this might lead to wings being damaged, but I never saw any evidence of that.
Did I say ‘disconcerting’? The sound was alarming, and I wanted to find some way to warn the other male who kept invading the pergola that he should buzz off and cause trouble elsewhere. It was quite obvious that the intruding male was a poor learner – or was addicted to the sugar water. It didn’t matter how off he was chased off; he would return. A puzzle I can’t answer is about the females. Some (well, one at least) were sometimes (rarely) allowed to use the feeder, and on a few occasions I would see both a male and a female sipping up the sugar water at the same time; however, an outsider female was chased off immediately, and I seldom any allowed to drink actually managing to get more than a quick sip.
Despite the aggressive behaviour shown to outsiders, ‘my’ hummingbirds were remarkably tolerant of me. It didn’t take long for them to ignore me sitting in a chair less than ten feet away from the feeder. It took a little long for them to accept the camera with its lens directed toward the, but eventually, and somewhat cautiously, that was accepted too. I must have taken scores of photographs of hummingbirds feeding and in flight. I fact, it was a bird in flight that provided some of best images, and I have used shots of hovering hummingbirds in calendars over the years.
The more you study hummingbirds, the more fascinating they become. Overall, their relatively compact bodies combined with bladelike wings enable them to fly in any direction, or hover. Their legs are short, with no knees, three toes pointing forward and one backwards. I have learnt they don’t walk on the ground or hop, but rather shuffle laterally, using their feet to perch (and to grab feathers of opponents!). Moreover, they use their legs rather like pistons, pushing them up to gain some thrust as they begin to fly, and then they tuck their feet under the body, creating a sleek body suitable for aerodynamics!
That’s not all. Studies of their brains suggest they have in enhanced ability for perception and processing of fast-moving visual stimuli encountered during rapid forward flight, when insect foraging, in competitive interactions, and during high-speed courtship. They have a fourth sensitive visual cone in their eyes (humans have three cones in their eyes) that detects ultra-violet light, helping with their colour discrimination, and it is believed this may play a role in flower identity, courtship displays, territorial defence, and predator evasion, as they would be able to see as many as five non-spectral colors, including purple, ultraviolet-red, ultraviolet-green, ultraviolet-yellow, and ultraviolet-purple.
Finally, as you might have guessed, hummingbirds are overwhelmingly nectarivorous, and they are the only birds for whom nectar typically comprises the vast majority of energy intake, with their long, probing bills and tongues which ensure their rapid take up of fluids. They are capable of extracting over 99% of the glucose from nectar feedings within minutes and have co-evolved in complex ways with flowering plants; thousands of American species can only be pollinated by hummingbirds. Flowers which are attractive to hummingbirds are often colorful (particularly red), open daily. However, it’s not just nectar they seek. Most, if not all, supplement their diet with the consumption of insects.
Though not as insectivorous as once believed, and far less so than their relatives, such as the swifts. About 95% of individuals from 140 species in one study showed evidence of arthropod consumption, while another study found arthropod remains in 79% of over 1600 birds from sites across South and Central America. Typically, they pursue small flying insects, but they also eat spiders, pulled from their webs. In fact, spiders are a common prey item, along with flies, wasps and ants. However, nectar is still the major source of food. Estimates based on time budgets and other data, suggest the hummingbird diet is generally about 90% nectar and 10% arthropods by mass. That ties in with another observation. Hummingbirds do not spend all day flying, as the energy cost would be prohibitive; the majority of their activity consists of sitting or perching. Hummingbirds eat many small meals and consume around half their weight in nectar (up to twice their weight in nectar, if the nectar is 25% sugar) each day.
Despite all that eating. I still think of hummingbirds as slight, little wisps in the air. Perhaps that is one of the reasons they pop up in literature. The Hummingbird’s Tale is an Amerindian story told by Pierre Rabhi:
One day, a long time ago and in a faraway place, or so the legend goes, there was a huge forest fire that was raging in the countryside. All the animals were terrified, running around in circles, screaming, crying and helplessly watching the impending disaster.
But there in the middle of the flames, and above the cowering animals, was a tiny hummingbird busy flying from a small pond to the fire, each time fetching a few drops with its beak to throw on the flames. And then again. And then again.
After a while, an old grouchy armadillo, annoyed by this ridiculous useless agitation on the part of the hummingbird, cried out “Tiny bird! Don’t be a fool. It is not with those minuscule drops of water one after the other that you are going to put out the fire and save us all !”
To which the hummingbird replied, “Could be, but I’m going to do my bit.”
Not just offering us a story about patience and perseverance. Here’s D H Lawrence, who wrote a poem on the topic of ‘Hummingbird’:
I can imagine, in some otherworld
Primeval-dumb, far back
In that most awful stillness, that only gasped and hummed,
Humming-birds raced down the avenues.
Before anything had a soul,
While life was a heave of Matter, half inanimate,
This little bit chipped off in brilliance
And went whizzing through the slow, vast, succulent stems.
I believe there were no flowers, then
In the world where the humming-bird flashed ahead of creation.
I believe he pierced the slow vegetable veins with his long beak.
Probably he was big
As mosses, and little lizards, they say, were once big.
Probably he was a jabbing, terrifying monster.
We look at him through the wrong end of the long telescope of Time,
Luckily for us.
What an extraordinary image. A monster hummingbird with its long beak and buzzing wings, it sounds like something in a fantasy novel. An addition to demons, ghosts, flesh-eating monsters, now I have to worry about hummingbirds six feet long, ready to suck my blood! Thank you, Mr Lawrence. Why couldn’t you have stuck with Kangaroo and Lady Chatterley’s Lover?
