Why Do Scientists Collect Specimens?

Later that afternoon after releasing the odd unwanted bird from our nets, we finally caught a male black manakin. Like clockwork each team member assumed their roles for the preparation of this specimen. The title of today's post is a question I asked myself that day on that trip: why do scientists collect specimens? This is also a question I have been asked many times before, and discussion sometimes ended in a heated debate. Like the majority of research topics, the benefits of specimen collecting are mostly indirect and sadly unappreciated.

At its most basic, a specimen serves as definite proof that a species lives in an area. Wrong identifications are reduced, as the specimen is readily available for review. This is useful when new species are discovered, as an extensive amount of work must be done before it can get its name as a species. But this is far from being the only purpose of a specimen.

A specimen itself can represent an almost limitless amount of data. When we collected our prize, we took measurements of its morphological features, blood and feather samples from various portions of its body. When we processed and prepared it as a specimen, samples were taken from parts of its brain. Its organs were measured and collected in such a way that would ensure that it would be viable for research many years from now. Nothing was wasted.

(Us preparing a blood sample)

In our case, the blood of our bird would be used for DNA studies, while its digestive tract could be used to study its diet. Instead of killing multiple animals for different studies, only a few have to be sacrificed for collection in a single expedition, and scientists who are not able to make it out into the field can work on the animal from their lab.

Another question I often get asked after explaining this is: why do scientists keep collecting specimens? Isn't a single one enough? The answer is "not quite". The first reason being that of research design: the more individuals you sample, the more reliable any conclusions will be. For example, if someone were to judge the entirety of humanity on whether or not I liked chocolate, they'd conclude that chocolate was a torture device fed only to the masochistic.

(Seriously, look at that stuff.)

The second reason is that a specimen is like a photograph; a single moment in time, captured. An animal is affected by its environment and the factors present during its life. These affect its characteristics, making it a representative of the time period and the location from which it is taken. As the development of new methods of research continues, we may find ourselves in future with new capabilities, new questions to answer, and the specimens to answer those.

There's an inherent irony to be had in killing the same animals one is trying to save, but there's a purpose. In the end, research will benefit animals and humans alike. Conservation decisions cannot be made without understanding a species, and medical breakthroughs might be waiting. From the sacrifice of a few, we can gain the data to save far more. Scientists are not evil creatures merely out there to murder everything we see.

Out of the Camp and into the Jungle

When I left off last, we just set out walking in the early hours of the morning. As I mentioned before, night time in the field is colder than it is in town. This is feeble, though, and fades as soon as the sun is properly awake. Thankfully we reached the trail into the forest, before the heat picked up, and found ourselves under the shade of the trees.

(The forest)

Dennis, our guide, was sure footed, maneuvering his way within the jungle at a blistering pace, leaving the rest of us behind. (As I became more experienced, I learned this is true of all amerindian guides). Willow, on the other hand was at least a foot taller than I was (and two or more feet taller than Dennis), and kept up with relative ease. Lainy and Claire were accustomed to this, and kept their pace well, leaving Leram and I struggling. Every now and then Leram or I would get distracted by something we saw in forest, or simply just by the surroundings themselves. Occasionally they would all stop for a second and point off in the distance, hearing a bird call we hadn't, in a direction we were unsure of.

(Distractions like the lichen on this rotten stump)

(Apparently green is a distracting colour in the forest)

This went on until we stopped for a short break. Willow produced a portable speaker system and played the call of the bird we were searching for, to familiarize us. Then, handing us some bags of nets and rope, her and Claire went off by themselves to investigate a site further away. The rest of us head off in the opposite direction, searching for the elusive black manakin.

The call of the black manakin

(funny enough, this is the very same call she played for us. 

imagine the smile I had when I found it online)

During our hour or so of walking, we heard them maybe only once. The calls of birds in the wild are many and varied, and as such, without experience, their identification is difficult. There are other more indirect methods one can use to find animals, though. In this case, as Lainy told us, manakins were especially fond of Melastome berries (family: Melastomataceae), and after locating a few of these and some fruiting trees, we found our sites and set up the mistnets.

(Mistnets being set up)

The setting up and of mistnets is similar to packing for me; something I've gotten quite adept at over time, but also a minor inconvenience I will continue to rue every single time without fail. Like packing, I'll discuss in more detail later on. Mistnetting is a passive method of surveying, so most of the time mistnetting is spent simply waiting, and walking. Like all methods, though, there is a certain danger posed to the animals being sampled. Birds have a risk of overheating or getting soaked in the rain, and as such, mistnets must be checked every hour without fail. Our distance from camp made walking back and forth completely inefficient, so we found a small clearing with some logs, and there we sat for the majority of the time we were there.

It's things like these, though, that make fieldwork so great. In the lack of technology, you either spend time with the surroundings, or the people you're with. Lainy, who had been exhausted on the bus and did not speak much, was now quite animated and we soon became well acquainted. When there was no conversation, often there was the wind blowing through the leaves, or the odd bird calling in the distance, or even, just a comfortable silence. Soon, we caught a anticlimactic manakin female in the nets. After taking the measurements, Lainy released her, and we set off to camp for lunch.

The Manakins

There are stark differences with the person I am at home versus in the field. Generally, I struggle to wake up on time every morning, yet when I'm out camping, I often find myself awake earlier than I need to be. My attempts to bridge the two have been met with little success, probably because unlike Georgetown, Guyana (my version of civilization), the temperature in the interior dips dramatically at night. On my first night out, I probably would have found myself awake and freezing way earlier had Leram not lent me an extra thick bed sheet which he'd brought along. Ironically enough, it was he complained about cold the next morning.

Nevertheless, we were both up in good time, and after packing our bags with the supplies we'd need, the entire team set out just after sunrise. We were not only with Willow and Lainy, but two master's students, Justin and Claire. They were all there for the same reason: to study manakins.

Manakins, the birds of the family Pipradae, are one the most showy groups of the neotropical songbirds. In addition to their flashy and sometimes ridiculous colours, manakin males are most noted for the fact that they dance. Yes, they dance.

(The Red-capped Manakin (Ceratopipra mentalis) From the PBS Documentary "Deep Jungle - New Frontiers")

(Lance Tailed Manakins (Chiroxiphia lanceolata) performing for a female. At the end of this paired mating dance, only one male gets to pass on his genes)

Manakin females are especially picky. As a result, males from within the family have evolved elaborate mating rituals in order to impress them. The Golden Collared Manakin (Manacus vitellinus) goes as far as clearing a section of the forest floor and darting from twig to twig which clapping its wing bars together (see clip above for slow motion video) to produce clicks. 

(The Golden Collared Manakin mating ritual)

The cost of these complex mating behaviours is the large amount of brain power they require. Male manakins have to be able to perform these actions with an incredible amount of dexterity, while females need to be able to see the subtle differences between two dances to determine which is the better mate. The male manakin brain actually increases in size during the mating season specifically to accommodate this. All for the purpose of passing on their genes.