The hidden world of hummingbirds

The aerobatic skills of Life Story’s booted racket-tail hummingbird are just one example of how this fragile bird equips itself for a tough world

Life Story’s booted racket-tail hummingbird (Ocreatus underwoodii) uses its formidable flying capabilities to slip past its larger relatives unnoticed, winning the competition for the best flowers despite its tiny size.

But when confronted by its own kind, the juvenile takes its chances in hummingbird “fight club”, showing its delicate looks can definitely be deceiving.

Here are seven more secrets of hummingbirds' little big lives.

1. 'Hummers' are always on the go

Hummingbirds hover by flapping their wings 50 times or more a second, which creates the humming sound they’re named after. They average speeds of 30mph (42kmh) which is useful for those species who face migratory journeys of up to 2,000 miles (3,200km).

To sustain this breakneck activity, a hummingbird’s heart beat has been measured as high as 1260 beats per minute and as a result they also need to eat a lot. They consume more than their body weight in energy-rich nectar daily, with some visiting more than 2,000 flowers a day just to avoid starvation.

2. They love sugar, even though they shouldn’t

Scientists have discovered that hummingbirds lack the T1R2 gene which allows most mammals to taste sweet foods, yet somewhere in their evolution their sweet tooth returned, allowing them to use nectar and rapidly spread out into new areas.

Maude Baldwin’s video shows a ruby-throated hummingbird’s clear preference for sweet things, rejecting plain water in the top feeder for sucrose in the bottom one, from which it enjoys several good, long slurps.

3. They have marvellous metabolism

Hummingbirds are unique among vertebrates in being able to use both components of sugar - fructose and glucose - super-efficiently, moving it at speed from their blood to their muscles, University of Toronto Scarborough research showed in 2013.

Co-author Kenneth Welch said if a hummingbird were human-sized, it would have to drink a can of fizzy cola every minute to keep going - all while maintaining its famously svelte figure. 

4. Those feet weren’t made for walking

When they aren’t flying, hummingbirds like to just sit and rest, which is a good job because their feet aren’t developed for walking and are just about suitable for perching. Many species can even go into a hibernation-like state called torpor to conserve valuable energy when needed.

5. Their flight technique is halfway between birds and insects

As Life Story’s booted racket-tail demonstrates, hummingbirds are incredibly manoeuvrable, able to hover and dart in every direction - even backwards and upside down.

But a study of their aerodynamics dispelled the belief that their tactics are the same as that of large insects like hawk moths.

The authors showed hummingbirds have not evolved symmetrical hovering – equal lift between down and up strokes – because their wings are made of feather and bone making them less flexible than insects’ wings.

Instead, hummingbirds gain three quarters of their lift from the downstroke and just a quarter from the upstroke. Other birds rely 100% on the downstroke.

6. Pilots and F1 drivers have nothing on them

Hummingbirds’ aerial feats aren’t only reserved for feeding and aggression, some are displays of courtship.

Male Anna’s hummingbirds (Calypte anna) were filmed achieving speeds “greater than the top speed of a fighter jet” by a US researcher whose stuffed models of females enticed the males into their extreme dives. 

Another study also showed the same species of hummer shakes its head with such acceleration that they can reach a g-force of 34, well over the 6g typically encountered by Formula 1 drivers.

The physically demanding manoeuvre is completed in mid-air to remove water from its feathers during wet weather.

7. Engineers are still learning from them

Being small and remaining relatively still while hovering makes the hummingbird the perfect muse for flight engineers trying to perfect their craft.

Studies using high-speed cameras have so far discovered how the birds bend and flex their wings to optimise their wing shape for staying in the air.

Research has also shown that the wings of the best hummer are more efficient than the blades of the world’s most advanced micro-helicopters, because they use less power to lift their weight.

Watch the booted racket-tail hummingbird learn to stand its ground in episode two of Life Story at 21:00, Thursday 30th October, BBC One.