Our First Two Subjects

On Sunday, we finally caught a few birds and spent the rest of the day training them. We ended up with a beautiful little male festive coquette and female (we think so now) saw-billed hermit.

 

The male coquette (left) is easily distinguished from the female by his much more brilliant iridescent green forehead and the almost comically festive frills (bursting from his chin and cheek) that give him his name (when they have them at all, the female’s frills are not as ‘festive’). Both sexes are quite small. Ours weighed approximately 3.5 grams. Roughly the same as a female ruby-throated hummingbird (for those of you in the east) or as much as a well-fed rufous hummingbird (for those of you in the west). They have rather short tails and short bills. When the male was startled, he could expand his frills and crest. It was not unlike the spitting dinosaur from Jurassic Park (though much more beautiful and less intimidating).

 

 

Saw-billed hermits (right – a male) are thought to be among the most ancient species of hummingbird. And they look it. They are large (8-11 grams), and rather reptilian in appearance. They have very long bills and rather large legs (for a hummingbird – after all, the order of birds in which all hummingbirds reside is “Apodiformes” = “footless form”). In the past, I have only worked with much smaller North American hummingbirds. So, I was caught off guard by how strong the saw-bills are. And, as I found out later, they are vicious! They definitely try to bite. Now, with smaller species, this is a rather cute and harmless thing. But, saw-billed hermits are so named because the males have a distinct curved (and serrated) tip to their bill. It’s not going to break any skin (at least not mine). But, it pinches a little. Considering it’s a hummingbird, it’s quite ferocious. Aside from this, the saw-bills are rather unremarkable to look at (well, again, compared to other hummingbirds anyway). They are mostly an assortment of drab brown, white and black spots and stripes. They have fairly long tails, and they perch more more horizontally than other hummingbirds, while conspicuously bobbing their tails.

 

 

Our research centers on understanding the energetics and flight performance of hummingbirds along elevational gradients. To gain this understanding, we’re studying hummingbird metabolism and wingbeat kinematics during flight. Wingbeat kinematics are relatively easy to obtain (as long as you have an expensive high speed camera – check!). Recording hummingbird metabolic rate during flight is more complicated. This requires convincing a hovering hummingbird to stick its head up into a tube (at the back of which is a nectar source) while air is pulled into the tube past the hummingbird’s head. In doing this, we can record how much oxygen the hummingbird consumes, and how much water vapor and carbon dioxide it exhales while it flies.

 

So, training the hummingbird involves acclimating them to captivity (life in a small enclosure for a few days) and getting them used to feeding from a syringe which is either suspended from the top of the enclosure (for video/kinematic measurements) or inside the tube (for respirometric - i.e. oxygen/CO₂/H₂O -  measurements). I find that, compared to most wild animals, hummingbirds are easy to train. Still, that doesn’t mean that training happens quickly.

 

By Monday morning, we had two reasonably cooperative birds. We set about accumulating data. The coquette was a master flier, easily lifting almost any weights (small strings of beads hanging from a yoke around its neck) we asked it to bear. The saw-billed hermit was not a cooperative lifter. Unencumbered, she hovered like a champ. However, the moment even the smallest chain of beads was added, she proceeded to throw herself about, madly trying to rid herself of the nuisance load. Luckily, while the female saw-billed hermit wasn’t a good lifter, she was a champion mask user, keeping her head inside for dozens of seconds continuously. I almost never get this long a measurement from smaller North American species. So, we can be quite sure we are obtaining accurate data!

 

Following their service, the two birds were transported back to where they were caught and we released. We hope all they nectar we served was payment enough for their effort.