The Hummingbird Festival in Sedona

I just got back from the Hummingbird Festival in Sedona, Arizona. It was an honour to be invited there to present our work on flight.

Sedona Hummingbird Festival, 2017.

Photo by Maria Mahar at www.hummingbirdpictures.net

The audience at the festival had a ton of great questions and I learned a lot. For example, the Anna’s hummingbirds are a fairly recent arrival in Sedona, just as they are in Vancouver, because urbanization has also allowed the species to gradually expand its range east into the desert (as well as north). I wonder how that has affected the hummingbird community there? I also learned that it is pretty easy to set up an outdoor Drosophila colony as a protein source for breeding hummingbirds.

We saw the Grand Canyon and more bats, hummingbirds, and aura photographers than ever before in one place. Arizona has great insects, too. My favourite? The “pleasing fungus beetle” we spotted at Starbucks.

View from the south rim of the Grand Canyon

Photo by Charlie Croskery.

Flight school

Our research on hummingbird flight is featured in the July 2017 National Geographic!

The article is all about hummingbird science, and how new techniques are allowing us to see aspects of their behaviour that aren’t available to the unaided eye. You can read the print article here, see a beautiful video summary here, and another one here. Here’s one of an Anna’s hummingbird in a wind tunnel. He’s remarkably good at keeping his head steady as the wind ramps up:

The photographer, Anand Varma, took a great shot of my vision experiments at UBC that shows a bird perching in a strange, Tron-like environment of glowing green stripes:

Hummingbird in the virtual reality flight tunnel

Photography and video by Anand Varma in National Geographic.

Between getting the scene right, adjusting the lighting, and then waiting for the bird to act in just the right way, this one photograph took an entire week of work (hands on work that is, no photoshop!). Given all the other complex shorts in the article, it’s easy to see how the whole endeavour took a couple of years – much like a scientific study. Working with Anand that week, it was interesting to see how many other parallels there are between what he does and our research. A lot of trial and error, a lot of patience, and a lot of coping with the quirks and surprises of animal behaviour.

The article ends with a scene from the summer when the writer, Brendan Borrell, spent a couple of days with me in the lab. I have the honour of being described as emerging from the lab with a “sheen of sweat” on my forehead. It is embarrassing, but true! It was a hot day and we were working hard in that room.

There is also a nice editorial about the project here.

A murder and a mutant

I woke up the other day to see this:

A little closer:

Those aren’t leaves covering the trees – they’re crows! There must have been a few thousand of them (the picture only shows part of the flock, which extended to cover several other trees and rooftops). This is the third time this winter that I’ve seen a mega-roost in downtown Ottawa. Each time it has been on days that are much colder than usual. By noon, the flock had dispersed.

We had more bird encounters in Quebec last week where we saw a partial albino black-capped chickadee:

Here’s a black-capped chickadee with regular plumage, for comparison:

In domestic birds, partial albino (pied) mutations are recessive and fairly rare. It took about 100 years of cockatiel breeding before the pied mutation was established in the US, in 1951. I can’t find published numbers for chickadees, but bird banders counting mourning doves have recorded only 1 partial albino among 10,749 individuals. So this was probably a pretty rare bird! And here’s Ada, no longer impressed by a regular old chickadee:

Bird-inspired drones

This Christmas the strong winds decorated the trees with shiny new drones:

(photo by Rod Croskery)

Drones of the future are going to get a lot more maneuverable.

A group at Imperial College London has now built an aquatic diving drone with wings that can tuck in for protection during rapid plunges, inspired by the hunting behaviour of seabirds in the family Sulidae (gannets and boobies).

And a Swiss team has developed a drone with feather-like elements that allow the wing to fold into a range of configurations, analogous to the way birds can overlap their wing feathers. This allows the drone’s wings to be adjusted to suit the conditions – reducing wing area in strong winds, for example.

These advances should make it possible for drones to maneuver in a greater range of tough-to-access environments, just like birds.

Both studies are published in a new issue of Royal Society Interface Focus:

Siddall et al. Wind and water tunnel testing of a morphing aquatic micro air vehicle.

Di Luca et al. Bioinspired morphing wings for extended flight envelope and roll control of small drones.

How hummingbirds control flight

We have a new study out on how birds use visual cues in flight. Here is a summary:

Thanks to Charlie for helping to capture the video footage! The study is a collaboration with Tyee Fellows and Doug Altshuler at UBC.

For the experiments, we used eight high-speed black & white cameras to capture the entire length of the 5.5 metre-long flight tunnel (I only had space to show two in the Youtube video above). The cameras were part of an automated tracking system that tracked the birds’ motion, and determined the birds’ 3D flight paths from the different camera views. This works similar to the way multiple cameras are used to make 3D movies.

Hummingbirds were great subjects, not only because they are incredible fliers, but also because they are sugar fiends! They have to feed every 10-15 minutes throughout the day. This meant that we were able to design big experiments and test a wide range of visual conditions.

Here are two other clips that illustrate the data from the tracking system:

The best part about this project was that we started with a pilot study that seemed like a failure, at first. We tried to repeat what had been previously shown for other birds (based on a pioneering study of budgies), but we did not see the same results. At first, that can be pretty disappointing. But it also gives you the chance to think of new ideas, and then figure out ways to test them. I think this evolution from failed experiments to ones that work is the most exciting part of science! The catch is that it can take years to get there. I really started to appreciate this once I began working with birds in the lab.

Dakin, Fellows & Altshuer. 2016. Visual guidance of forward flight in hummingbirds reveals control based on image features instead of pattern velocity. PNAS, in press.

Peacock physics

We have a new paper out!

Biomechanics of the peacock’s display: how feather structure and resonance influence multimodal signaling

In this study we describe the rapid feather vibrations that peacocks use during courtship. These vibrations – at a rate of about 26 Hz on average – represent a substantial mechanical and metabolic challenge for the birds, especially given that they are performed using a massive array of feathers with widely varying lengths.

IMG_3139

A peacock shows his stuff. His train feathers range from 10 cm to > 150 cm in length, and the whole thing weighs about 300 g. Photo by Roslyn Dakin.

We recorded high speed videos of peacocks displaying in the field. We also used lab experiments to test whether the peacocks move their feathers at resonance (which would be an efficient strategy), and to understand how the colourful eyespots can remain so steady during these vibrations. One surprising result was that the peacocks with the longest trains actually used slightly higher vibration frequencies overall – making their displays a greater challenge to perform. The next step is to understand how these feather motions influence the iridescent colour patterns as viewed by the peahens (the females), and ultimately, the hens’ choice of a mate.

Media coverage has been great – here are a few of my favourites:

…and Suzanne reports that her husband met a couple in the Netherlands who had just read about our study in that newspaper. Pretty gratifying to hear that!

The videos associated with the paper are available here.

Dennis Hlynsky’s small brains en masse

Dennis Hlynsky’s videos are among the best things I’ve seen online recently. Check ’em out:

Hlynsky uses frame-blending to great effect, to give you a sense of overall motion trajectories. When he turns his lens on animals, the results are both beautiful (see fruit flies paint a still life here), and an exciting way to visualize huge amounts of data. It’s got me thinking I could use this method to illustrate the 100s of hummingbird flights in our latest experiment here at UBC in a single animation.

Thanks to Suzanne Amador Kane for pointing these out to me!

Feel the vibration

In between field work, I’ve been making a lot of videos lately – mostly for my students in the summer course in Ecology and the Environment. But my latest creation is entirely different: it’s for the upcoming American Ornithologists’ Union (read: bird nerd) conference.

It features slow-motion clips of peacocks vibrating their train feathers during their courtship displays. I used a special high-speed camera to film this behaviour at 210 frames per second – it was incredibly difficult to do, because the high-speed camera requires that you get really close, and males only perform the vibration when a female is nearby (and not a human one!). In the end, I was able to coax some hungry peahens practically into my lap by slowly doling out the treats. This allowed me to film males displaying at the females from just a couple of feet away.

From these videos, I estimated that peacocks vibrate their eyespot feathers at a rate of 25 Hz (i.e., the feathers move back and forth a whopping 25 times each second). That’s incredibly fast, but it’s hardly record breaking for birds. For instance, Teresa Feo and Chris Clark recently showed that hummingbirds vibrate their tail feathers at a rate of more than 80 Hz to produce a buzzy trill-like sound during their display dives. However, the hummingbirds do it passively, I believe.

Other birds are also making the news these days for their choreographic skills. Anastasia Dalziell and her coauthors at the Australian National University have shown that superb lyrebirds actually coordinate song and dance during their remarkable courtship displays.

Further Reading

  1. Feo and Clark. 2010. The Auk 127: 787-796.
  2. Dalziell et al. 2013. Current Biology. In press.

Nest in the city

One of the most incredible things about peafowl is how well these birds thrive in the suburbs. There were hundreds in Arcadia, CA, where I studied them, and every once in a while I hear about some other town where they’ve taken over – Orange County, Palos Verdes, Miami – they even disperse and occasionally pop up somewhere new (like here, or here). I’ve been told that in India (where the species is originally from), flocks also tend to settle down in villages. (And the name for a group of peafowl? A muster!) And peacocks are now on the cover of a book on urban birds1.

So what makes peafowl so much better at urban living than other, similar species?

It could be that they’re catholic about their diets, or that they’re tolerant of a broad range of environmental conditions2. Other research has suggested that, in mammals at least, successful invaders tend to have relatively large brains3 – possibly because a large brain confers the ability to respond flexibly to new situations. American crows fit this theory, as an urban success story with relatively large brains. But peafowl are some of the smallest brained birds out there, when you consider brain size relative to body size – and pigeons, starling and house sparrows aren’t particularly well-endowed, either. So what if it has more to do with how they use their brains to adapt?

A new study points to an intriguing benefit of city life for some birds, and it has me wondering about learning as a mode of urban adaptation. Apparently, some urban birds use cigarette butts to build their nests – and researchers have now shown that the cigarette butts actually improve the living conditions for young birds.

Continue reading →

Is animal care due for an update?

Canadians will fiercely defend nearly any Canadian-made thing, and we have an uncanny ability to keep track. Insulin? Discovered by a Canadian. The telephone? Also Canadian. Sir Sandford Fleming and his time zones? Canadian too. Tom Cruise? Spent his childhood here.

At the philosophy symposium here in September on ethics and animals, I learned of yet another point of pride: our national body governing the care of animals in research was one of the first in the world. Although the first official law to prevent cruelty to animals was passed in Britain in 1876, and the US had its Animal Welfare Act a few years before Canada’s Council on Animal Care (CCAC) was official, the CCAC had its beginning in the early 1960s – and it was revolutionary at the time.

But is it due for an update?

Continue reading →

Neanderthals were into birds

Well, into their feathers anyway. Thanks to a new study out this week, we now have paleontological proof that Neanderthals collected birds for more than just food. They probably used bird feathers for decoration – just like we do – suggesting that we aren’t the only hominid species to have developed an artistic culture1.

The research team – led by Clive Finlayson – used a combination of archaeological and paleontological evidence from several different sites where Neanderthals lived during the Paleolithic, ranging from Gibraltar in southern Spain to sites in the near East. For each site, the researchers tallied up the number of different bird species found in the fossil record at the same time and place as the Neanderthals, and they discovered that certain species were most frequent. The most common species were raptors (like vultures, kites and golden eagles) and corvids (like crows and choughs). Crucially, the researchers found that the remains of these particular species are far more abundant at the Neanderthal dwellings than they are at other paleontological sites – suggesting that the bird bones were there for a reason.

Continue reading →

Elections are like peacocks

Both are loud, and both cause colourful flashy things to pop up on lawns everywhere. And much like elections, the peacock’s train is a costly endeavour. The species might be better off in terms of survival and abundance if they could just do away with those feathers. In terms of sheer waste, they remind me of the Green party pamphlets in our apartment building entrance way. They were stuffed blindly into all of the available mailboxes – which happen to be for street level businesses on our downtown block, not residents. Nice.

Peacocks and elections are both supposed to experience strong positive feedback effects. In politics, momentum can lead to rapid climbs in popularity. Sexual selection can be similar: as Ronald A. Fisher pointed out, exaggerated male traits can potentially evolve through a process of positive feedback. If enough females prefer the particular male trait initially, and the next generation inherits both the female preference and the exaggerated male trait, it can kick-start a runaway process of sexual selection to extremes.

Despite claims to the contrary, we don’t actually know whether Fisher’s runaway process contributed to peacock evolution. But it may be reasonable to assume that it played at least some role: positive feedback should set up easily so long as mate choice is not very costly for females2.

Thinking about peacocks gave me an insight that may have cured my allergy to all things political, at least temporarily. Not that I don’t care about the election – I do – but I can’t get over my frustration at the kinds of things that count as good arguments in the political sphere. Here’s an example: I’d like to learn more about the Green party, but they seem to support a whole lot of pseudoscientific nonsense. Apparently their health care platform includes homeopathy and various other forms of alternative medical quackery. How can we be sure they won’t apply the same less-than-rational approach to the environment? If only there could be “one true party”, I thought after the leaders’ debate – a notion that, briefly, made me wonder whether I might be a closet fascist.

This doubt came up again when I was reading an article in this week’s Nature about the effect of social media on research priorities. It focused on the controversial and totally unproven “liberation procedure” for MS – extremely popular in Canada but, oddly enough, nowhere else1. The article mentioned that Michael Ignatieff has stated his support for clinical trials of the treatment, despite the recommendation by a panel of CIHR experts that a clinical trial would be premature without further evidence from observational studies1. The authors of the Nature article – a group of doctors and medical researchers in Canada – ended up somewhere close to Ignatieff’s position nonetheless. They concluded that the benefits of a full-blown experimental trial might outweigh the costs if thousands of social media-influenced patients are travelling outside of the country to receive private treatment anyway, “exposing themselves to the risks and costs”1. In other words, popularity is an important – and rational – consideration when it comes to medical science.

I have two things to offer for election day. First, there is a good summary of where the major parties stand on science and research funding here. Some are a lot more rational than others.

On to the peacocks. Democratic elections, like sexually selected traits, are communal illusions. Money is another example. The more you accept them, the more you believe in them, the better they work.

References

  1. Chafe, R. et al. 2011. Nature 472: 410-411.
  2. Lande, R. 1981. PNAS 78: 3721-3725.

Another reason for eggs

Roman soldiers used them for protein1. In Mexico, men steal them from endangered sea turtles for their supposed effects on virility2. Bird eggs and roe, the ripe ovaries of fish, have a rich balance of proteins, fats and minerals – nutritionally, almost everything a predator needs. The whole point of these things is to feed something for an extended period of time. It’s no wonder eggs are so delicious.

The applications go beyond adding energy to our diets and structure to baked foods. Laying hens also contribute to medicine. Fertilized chicken eggs are used to grow viruses for mass production of vaccines. In 2007, scientists figured out how to genetically engineer hens to incorporate certain cancer-fighting proteins right into their egg whites, in a more efficient way to manufacture drugs that has been dubbed “pharming3.

This morning, enthusiasts have yet another reason to celebrate, since a new study suggests that bird eggs might hold even more promise for medical research.

It has to do with migration, but not the kind you’re used to hearing about with birds. Cellular migration refers to the movement of cells within an organism during growth or embryonic development. For a long time, biologists studying this behaviour focused on the movement of single cells in isolation. In the last decade, however, the focus shifted to cells moving in a large, cohesive group. This collective migration is a fundamental part of gastrulation and neural crest development – two of the necessary steps for turning a blob of cells into a fully formed embryo during development (watch a time lapse video of this process in zebrafish).

Collective cell movement, or epithelial migration, occurs on a grand scale during bird embryo development. Every fertilized egg contains a tiny blastula, the hollow ball of cells that will eventually become a fetus. Early on, the cells of outer blastoderm layer of the ball start to expand across the vitelline membrane that surrounds the egg yolk, in a process known as epiboly. Eventually, the expanding sheet of cells envelops the entire yolk – a requirement for the yolk sustain the embryo during its transformation from a ball of cells into a viable chick.

Bird embryo and yolk

A chicken embryo grows while attached to its yolk, because of epiboly. Modified from drawing by D.G. Mackean.

This around-the-yolk migration happens rapidly, within days. From the perspective of a single cell, it’s a feat that bioengineer Evan Zamir likens to “an ant walking across the earth”4. And we still don’t know exactly how birds do it, with their humongous yolks; so far, most research on epithelial migration has involved other organisms.

Continue reading →

A royal waste?

Giant pandas are in the news again, this time for their annual date night at the Smithsonian National Zoo in Washington DC. But hardly a day goes by without a report somewhere on the latest captive panda birth, strategic breeding attempt or panda relocation.

A blogger at the London Review of Books compared the bears to members of the British royal family: both are suffering from shrinking ecological niches and in serious danger of extinction, hanging on by virtue of their marketing potential. The similarities don’t end there. Giant pandas, like royals, are expensive to house, with a fee of over $1 million per year for a zoo to lease a pair from China. Naturally, the breeding activities of giant pandas are as intensely scrutinized as those of Prince William.

This entails some surprising efforts when it comes to the pandas. The history of captive breeding for Ailuropoda melanoleuca is no sordid royal affair. It’s long, and for the most part, pretty unfortunate; zoos have been failing to produce heirs to the panda legacy for decades.

For starters, it’s nearly impossible to get the bears to mate in captivity, and it’s not just their deficiency in the looks department, as comedian Mike Birbiglia suggests. Captive pandas can’t seem to figure out a working sexual position1. Females often start things off all wrong by lying down, but the males are just as clueless. This led to panda porn: zoos started making videos of pandas achieving copulatory success, as training tools for the more hapless bears2. Other attempts to use Viagra on pandas were less encouraging, but the porn worked – for females as well as males – leading to a boom in captive births in recent years3.

Giant panda cub

Visitors can pay to see the cubs at the Chengdu giant panda breeding centre. File photo modified from newssc.org.

Continue reading →

Groupthink

Which animal would use Facebook most, if it could?

My poll in class last week was a popular one – a fact that I couldn’t properly enjoy, since Charlie came up with it for me in a fit of brain-dead incapacity. Charlie’s Facebook question elicited chirps of excitement, compliments and even a few drawings on the response sheets. Here are the results, ranked by favour among the students:

  • Chimpanzees: So they have opposable thumbs, and can “use the spacebar” (is this actually important in Facebook?). A number of students gave bonobos special mention, since they would probably want to keep track of all their casual sexual relationships.
  • Dolphins: Highly intelligent, social, and they might also be interested in monitoring multiple sexual conquests. Dolphins and migratory whales could use Facebook to keep in touch while roaming widely over the oceans – the long-distance relationships of the animal kingdom. For some reason, students in different tutorial groups who chose dolphins were inspired to draw them for me as well. Coincidence?
  • Parrots and other birds: Especially in species that have high levels of extra-pair paternity, birds could use Facebook as a form of mate-guarding to keep tabs on their social partner1,2. There are other reasons to think that songbirds might easily make the transition to internet gossip. Female black-capped chickadees, for instance, eavesdrop on the outcome of song contests between rival males, and use this information when deciding on a mate3.
  • Eusocial animals: Like ants or naked mole rats (the only known eusocial mammal). A couple of students also mentioned highly social meerkats, since living in groups of 10-40 individuals would require them to keep track of a lot of social information.
  • Other yappy follower-types: hyenas, seals, lemmings, and Yorkshire terriers all got a mention.

Charlie and I discussed it over dinner at the Iron Duke. My first thought went to ants, for their extreme group lifestyle. The problem is that ants don’t really care about what other ants do or think about each other. Insect sociality is all about the greater good: worker ants toil away for the colony despite having no hope of reproducing on their own. Ok, so maybe the internet isn’t conducive to real reproduction either, but ants just don’t have the ego required. Plus, as one clever student pointed out, a colony of eusocial animals are all very close genetic relatives of one another – and she tends to block family members from Facebook.

Charlie mentioned peacocks for spending so much time on courtship and preening, but I rejected that one too.

Continue reading →