Tag Archives: Methods

Cognition in the wild, brought to you by the Rufous Hummingbird

Today’s date is 03/14 (that is, in the foolish countries that put the month number first), so it has become ‘Pi day‘. Few realise that it’s also Albert Einstein‘s birth date… and mine!

To celebrate, I’ve decided to write about my preferred animal behaviour topic (thus far): the study of cognition in the wild!

( ̄¬ ̄) Close enough

( ̄¬ ̄) Close enough

Why is it relevant? Because to understand the evolution of cognition in vertebrates, we need to examine animals’ abilities under natural conditions, where they face having to find food and mates, all the while evading all sorts of dangers. That way we can hope to identify some of the factors affecting the selection pressures at work. It is true that for some species, especially “smaller” ones, the line between the laboratory and the natural environment can get very blurry, if not inexistent. For “bigger” ones, though (like birds, mammals, and reptiles), the border is quite real. And those are the animals I’m interested in (again, thus far).

With doing something as messy as studying invisible processes in a rather uncontrollable environment comes great responsibility an assortiment of challenges. Let me list some of them as mentioned by Healy and Hurley (2013) in their review on ‘What hummingbirds can tell us about cognition in the wild’:

  • The participants may use different cues than in the lab, or use them differently, during tests;
  • Their ‘answers’ may not reflect the psychological dimension you’re trying to measure (an issue shared with all kinds of tests, I’m afraid);
  • How to make sure they’re motivated to actually participate?
  • What task to use?!?!! Meaning: what dimension are we going to choose to extrapolate their cognitive abilities??

Quite alarming, isn’t it? Well, it can be less so if you’re thoroughly prepared.

First, you need to find a “logistically amenable to testing” species which, in Healy and Hurley’s case, were rufous hummingbirds Selasphorus rufus. They focused on the males because those guys are territorial, so they fight off conspecifics from their patch, and feed frequently enough that nice amounts of data can be collected each day.

Rufous Hummingbird Selasphorus rufus. Credit: jessi.bryan on Flickr

Then, the species’ ecology should be such that you can formulate predictions about the abilities that might have been ‘encouraged’ by evolution, the same abilities that you’ll want to investigate. This requires, in particular, knowledge of their sensory ecology, of how they apprehend the world and might apprehend your experimental task.

I won’t go into too much detail here about the methods used by the authors and their colleagues in their experiments. They describe them rather well in their paper (see below for a direct link to it). But I will tell you this: it involves artificial flowers, arranged differently depending on the ability studied. As an example, in studying 3D spatial cognition:

… when flowers were presented on a vertical pole …, birds found it difficult to learn which one of five flowers was rewarded but when the flowers were presented along a diagonal pole, the birds were relatively quick to learn which was the rewarded flower (Flores Abreu, Hurley & Healy, 2013). Here it appears that the addition of a horizontal component to the flower’s location may have facilitated the learning of its vertical component.

Another set of findings they discuss are related to the use of colour, or lack thereof, in learning flowers’ refill rates – rufous hummingbirds use this cue “only when space is not relevant”. They also seem to possess a somewhat episodic-like memory, meaning they can simultaneously retain information on the what, the where and the when of an occurrence.

YES

YES

They conclude by stating that more data from comparative research is needed to continue figuring out the interaction between cognition and natural selection, especially the benefits of cognitive abilities as they pertain to particular animals and to their ecological demands.

This ‘required research’ business is very cool! Because an increased number of people understanding the necessity of it means that, maybe, just maybe, my own interests in the topic could one day neatly align with a supervisor’s and, who knows, some grants committees’…

Reference:

Healy, S. D., & Hurley, T. A. (2013). What hummingbirds can tell us about cognition in the wild. Comparative Cognition and Behavior Reviews, 8, 13-28. doi: 10.3819/ccbr.2013.80002 <– THAT’S THE DIRECT LINK

On crowd-sourcing in animal behaviour research

Science–Public (post illustration)

Science <–> Public

Or in science in general, really.

The basic idea is the following: what if researchers used the public as a bunch of data collectors? Organisations such as ‘Adventurers and Scientists for Conservation’ already engage people to become citizen scientists (more about them on their website).

Nelson and Fijn (2012) recently suggested that visual media could be extremely valuable for studying animal behaviour. Specifically, they discussed how YouTube video clips of play behaviour, given they met certain requirements, can help explore hypotheses and further ideas by providing inspiration. As they conclude:

… displaying behaviour using YouTube as a visual medium is an excellent avenue to report or illustrate findings in the field of animal behaviour, in addition to its potential for further observation and research.

For links to hilariously cute videos, I definitely recommend taking a look at their paper (see below)!

I have to say, this essay brought quite a few ideas to my mind. For example, why not formalise crowd-sourcing like this by creating an online platform dedicated expressly to citizen scientists’ recordings – video clips as well as photos? These wouldn’t need to be restricted to animal behaviour, either. I imagine a variety of content, from corvids playing in the snow to peculiar rock formations, accompanied by information on the recording (time, location, weather context, etc.).

Maaaybee I’m getting ahead of myself, though. Either way, I’m excited for the future and I’ll definitely be on the lookout for more projects actively bringing science and the public together.

What about you? Has content from social media ever been an inspiration for your research?

Reference:

Nelson, X. J., & Fijn, N. (2012). The use of visual media as a tool for investigating animal behaviour. Animal Behaviour, 1-12. doi: 10.1016/j.anbehav.2012.12.009

Salmon ACTUALLY use Earth’s magnetic field to find their way home

Five years ago, it was hypothesized that marine migrants, such as salmon and turtles, travelling long distances to reach their natal waters to spawn (a process known as natal homing) use geomagnetic cues to navigate to the correct area (Lohmann, Putman & Lohmann, 2008). Now, for the first time, there is empirical evidence to support this hypothesis.

Sockeye salmon Oncorhynchus nerka. Credit: Wikipedia.

Sockeye salmon Oncorhynchus nerka. Credit: Wikipedia

Adapted from Putman et al. 2013

Putman et al. (2013) analysed fisheries data spanning 56 years, from 1953 to 2008, that described the proportion of sockeye salmon Oncorhynchus nerka that took either the northern or the southern route to reach the mouth of the Fraser River, near Vancouver Island, Canada (see the above illustration). They examined whether these proportions were correlated with changes in magnetic field intensity and other environmental factors.

They found that, the more the magnetic field of a strait resembled the one of the Fraser River mouth, the higher the proportion of salmon that used it. It is as if they had previously imprinted on the magnetic field of the river, much like geese imprint on a parent some 13 to 16 hours after hatching, and were able to use this information years later during spawning migration.

The other significant factor affecting their itinerary was Sea Surface Temperature (SST). Years with higher SST were characterized by an increased propotion of salmon choosing the northern route, possibly because fish preferred colder waters.

Changes in magnetic field intensity, SST and the interaction between the two explain up to 66% of the variance in migratory route use.

This study employed a retrospective non-experimental design, which does have its shortcomings, including a multitude of possible confounding variables. Notwithstanding, these findings are crucial to understanding natal homing mechanisms and, as Putman et al. put it, “call for experiments on the navigation abilities of adult salmon as well as further investigation into the magnetic imprinting hypothesis”.

PS: I would like to thank my brother for drawing my attention to this study.

References:

Lohmann, K. J., Putman, N. F., & Lohmann, C. M. F. (2008). Geomagnetic imprinting: A unifying hypothesis for long-distance natal homing. Proceedings of the National Academy of Sciences, 105(49), 19096-19101. doi: 10.1073/pnas.0801859105

Putman, M. F., Lohmann, K. J., Putman, E. M., Quinn, T. P., Klimley, A. P., & Noakes, D. L. G. (2013). Evidence for geomagnetic imprinting as a homing mechanism in Pacific Salmon. Current Biology, 23, 1-5. doi: 10.1016/j.cub.2012.12.041

American Bisons Killed for Research

In the spring of 2012, I read Fuller’s (1960) paper on the “Behaviour and social organization of the wild bison of Wood Buffalo National Park, Canada”. It taught me that bisons (Bison bison) are decidedly very cool creatures. They have developed senses which allow them to detect danger from up to several hundred meters away, they produce a multitude of sounds in relation to the social situation, they run fast and swim with ease. The paper also taught me that researchers, and in all likelihood other people, killed bisons.

…Yup. Bisons were rounded up each year in ‘corrals’ where they were kept until the “slaughter”.

American bison Bison bison – PD

American bison Bison bison

Screen shot 2013-01-21 at 01.12.08

Why?!?!? Why did they do that!?! Maybe the answer is evident. Maybe I am ignorant, but I find these methods outrageous. Fuller later mentions cows’ and calves’ behaviour in corrals:

Screen shot 2013-01-21 at 01.13.07

Oh really, they bawl? Well that is a surprise. No, really, who would expect them to be freaking out in these situations?

Actually, Fuller himself shot at least three individuals for research purposes. At this point in the paper, my disconcertment was due mostly to the matter-of-fact tone of his writing.

Screen shot 2013-01-21 at 01.08.41

Screen shot 2013-01-21 at 00.44.03

Hahaha: “had to be shot”, as though he had no other choice whatsoever. Like, for example, let her stay with her calf, you know, the one that he shot. Or maybe not shoot the calf in the first place.

Granted, these were not the only ways that Fuller gathered data. He also stalked herds, did road and plane counts, thus observing bisons for long periods of time.

bison-60592_640I do not wish to undermine his research, which was genuinely interesting, but rather to express my astonishment at some of the methods of the past. I do hope the slaughters and unwarranted shootings are over.

Reference:

Fuller, W. A. (1960). Behaviour and social organization of the wild bison of Wood Buffalo National Park, Canada. ARCTIC, 13(1), 2-19. Retrieved from http://arctic.synergiesprairies.ca/arctic/index.php/arctic/article/view/3685