A "Murder" of Crows

Throughout history, humans have had the idea in mind that only us are unique and different, that we’re born special, and we are just superior to other animal species. The opinion of other animals being inferior, however, started to change in recent years. In the book Beyond Words: What Animals Think and Feel, Carl Safina said that “Animals know who they are; they know who their family and friends are. They know their enemies. They make strategic alliances and cope with chronic rivalries. They aspire to higher rank and wait for their chance to challenge the existing order. Their life follows the arc of a career. Personal relationships define them. Sound familiar? Of course. ‘They’ includes us” (Safina 1). After developing higher intelligence that allowed us to become the dominant species of planet Earth, we forgot about the fact that we are not something uniquely distinguished from kingdom animalia. We are just a species of animal, nothing too special. Thinking and consciousness are also not something that’s unfamiliar to them. In this literature review essay, I’m going to review some studies done on New Caledonian Crows. I will use evidence proven in three of the studies to prove that New Caledonian Crows are intelligent species. They can learn from experience and observation, and develop their own way of thinking and use tools effectively.

Crows are intelligent

Historically, the crow family is not welcomed. Crows are often seen to be representative of death, disease, and bad luck. A crowd of crows can be described by “a murder of crows”, which the word “murder” refers to killing and unwilling deaths. Masaki Okuyama from North-Kanto Regional Office for Nature Conservation, Japan, in his article Administrative Measures against Crows included laws of Japanese government that act against crow protection. “In Tokyo, the government has launched an urgent project, including aggressive capture programs, to decrease the population of crows in response to rising complaints from urban residents about crows” (Okuyama 2003). Complaints include reasons like crows are noisy or untidy, and crows can potentially be harmful to agriculture.

However, in 2009, a zoologist from the University of Cambridge found that a rook from the crow family could drop rocks to a pitcher from large size to small size in order to reach water in it. It was able to figure out that larger rocks can fill the pitcher quicker (Kluger 13). In the 21st century, scientists have started to realize that crows are actually one of the smartest bird species in the world. They are able to manufacture and use tool-shaped tools (Kluger) and can think complicatedly. Now, more and more research about crows is done to discover the secrets hiding in their brains.

This review’s purpose is to prove that New Caledonian Crows are able to think and learn through the process of them trying to solve problems using tools. First I will show how their behaviors while facing problems are related to their wild habitat environment by presenting a study in 2011 by Alice M. I. Auersperg et al., comparing New Caledonian Crows with Keas called Flexibility in Problem Solving and Tool Use of Kea and New Caledonian Crows in a Multi Access Box Paradigm. Then I will show a study made by Jackie Chappell and Alex Kacelnik in 2001 called Tool Selectivity in a Non-Primate, the New Caledonian Crow (Corvus Moneduloides), which proved that they understand their needs while using tools to solve problems, and they can think their way to the correct tools to use. Finally, I will present a study by Auguste M. P. von Bayern et al. in 2009 called The Role of Experience in Problem Solving and Innovative Tool Use in Crows, which shows higher potential intelligence of New Caledonian Crows, that they present likely behaviors of trying to figure out the triggering preconditions of trap doors made by humans. In the concluding section, I will return to the fact that since now we know that crows are more intelligent than what we thought in previous centuries, should we reconsider what’s the meaning and definition of animals, and how we should treat them afterwards?

Although the crow family is one of the most intelligent species in birds, they are not the only species that understand to use tools to help them. How are their behaviors different from other tool-using birds when approaching the same problem? Alice M. I. Auersperg from the Department of Cognitive Biology, University of Vienna and her fellow researchers published the article Flexibility in Problem Solving and Tool Use of Kea and New Caledonian Crows in a Multi Access Box Paradigm on Plos One. Their study conducted an experiment on both kea and new Caledonian crows to compare their ability to solve problems and adapt the way of solving it. A clear box with food in it is provided with 4 possible ways to get to it. New Caledonian crows are more gentle to the box and more used to using strings as that is one of their familiar tools in the wild, while keas try to destroy and damage the box and show more curiosity. While multiple keas reach their heads into the box for food, New Caledonian Crows are more cautious and instead use tools to reach the food inside. The final result shows that New Caledonian Crows have a more efficient and precise problem solving skill using tools than keas (Auersperg 5).

The conclusion of this experiment suggests that the actions taken by keas and New Caledonian Crows are likely related to their natural habitat environment. While keas live in a more harmless environment with no predators aiming on them, they are more willing to try out and explore unknown things themselves. New Caledonian Crows, on the other hand, live in a more cruel environment in the wild, in which they need to fight for food and steal from prey of other predators, they are more cautious when handling potential dangers (Auersperg 6). Although crows and parrots are both clever bird species, the result of the experiment clearly indicates that New Caledonian Crow is the cleverer species among the two.

Humans and only a small portion of primate species were observed to have high intelligence and can use tools to solve problems, and it is until recently that researchers started to find evidence that crows, being a species that’s not one of primates, are also intelligent. Jackie Chappell, animal behavioral scientist from University of Birmingham, and Alex Kacelnik, zoologist from University of Oxford, published the article Tool Selectivity in a Non-primate, the New Caledonian Crow (Corvus Moneduloides) on Springer Verlag in 2002. This research article opened the gate of knowledge about animals, which we now know that intelligence is not something unique to primates. The article conducted two experiments on New Caledonian crows, the first one placed tools with different lengths in sight for them to use to extract food from a tube, and the other placed tools away from sight with the same procedures. Those subjects were able to mostly figure out a tool with suitable length for the first experiment, but sometimes fail but try to correct their mistakes by replacing the tool with the more accurate one in the second. In successful cases, sometimes the tool used is still shorter, but “this was possible because it used the ‘tip’ holding technique and held the tool very close to the end, inserting part of its beak into the pipe” (Chappell 75). The tool with the longest length is not often used because its downside is hard to manipulate. It shows that crows are able to learn about finding the correct solution by sight, and they clearly understand the situation when they choose one of the shorter tools.

The experiment proves that New Caledonian Crows are aware of what they are facing and what they should do to solve problems. When selecting tools that are not matching, they know that they made a mistake, and they know exactly how to correct that. This gives us an understanding of crows’ intelligence level, but what we don’t know yet is that this might not be their full capability. They might be even smarter, smart enough that simply solving a single problem is not enough to satisfy their curiosity.

When a Maths teacher teaches a student, he or she wants the student to understand the mathematical formulas. He needs to learn how to solve all sorts of problems similar to that, not just one problem. Crows do that too. Animal behavioral scientist Auguste M. P. von Bayern from University of Oxford, et al., published the article The Role of Experience in Problem Solving and Innovative Tool Use in Crows on Current Biology. The article conducted an experiment and studied crows learning from their experience. There are two groups of crows, one has seen a stone opening a trap door before and the other hasn't. The first group was able to perform the task of dropping a stone to open a trap door for food themselves while the second can't. It suggests that crows can learn from their observation and perform similar tasks based on their experience (Bayern).

Besides, something interesting happened during the experiment, which is that a crow dropped a feather on the trap door as an experiment. This may be a sign suggesting that the crow is instead trying to figure out the exact theory of how the device works rather than just getting food for this particular try. If more research is done about this area, it might lead to a new possibility that our current understanding of crows’ intelligence is still not complete enough. These creatures may be even smarter than we thought.

In conclusion, New Caledonian Crows are intelligent. They are able to adapt their cautious habits in the wild to problem solving using tools, and they are also capable of not just selecting the right tools for the right tasks, but also learning from watching other individuals perform a task, and develop a possible theory of how things work. Now since we know that New Caledonian Crows are intelligent and adaptive, we should really reconsider the negative images we impose on them, that they are representatives of death and disease, and are signs of bad things happening in the future. Besides, human kind is destroying their natural habitat. Since those crows are not welcomed in residential areas by humans, we should at least give them their natural habitat back, right?

Crows are facing problems

In 1970, psychologist and philosopher Richard Ryder introduced a new concept called “speciesism”. Same as infamous racism and sexism, speciesism is the action of discriminating against specific species. He came up with a fundamental definition of animal rights, of how humans should measure treatments to a specific species is right or wrong. He said that it is measured by animals’ ability to feel pain. If they have complicated enough brains that can feel pain the same way humans do, we should not treat them badly and should instead give them rights. Crows are conscious and intelligent animals. It is not hard for us to predict that they have a fully functional pain system built in their brains. However, it is legal in the USA to hunt crows. Farm owners see them as pest animals because crows which habitats are close to a farm would prey on ducks and crops, which would cause economic loss to the farm. It is absolutely normal to hunt crows in the USA, just like nobody cares about how many rats or mosquitos are killed each year, there isn’t even statistical datas to calculate how many crows are killed each year in hunting events. There are companies which help kill crows for farms and clubs for people interested in hunting crows gathering up each week for hunting events. The number of innocent crows dying each year must be enormous. Besides hunting, the accelerated climate change due to human activities is also causing some crow species to be endangered, some even facing extinction.

Mariana Crow is a species of the crow family whose natural habitat is located in Mariana Islands. Steven G. Fancy, from Biological Resources Division of Pacific Island Ecosystems Research Center, published the article Status of the Mariana Crow Population on Rota, Mariana Islands on Micronesica. The article is about a research survey on the population of Mariana Crows on Rota, Mariana Islands. They used a method called variable circular-plot (VCP) to count the population of the crows on the island and recorded data every 8 minutes. Their previous data collected in 1982 showed that the total population of Mariana Crows was about 1348. The new data collected showed that there are only 592 crows left (Fancy 1999). The comparison indicated a 56% decrease of Mariana Crow population, suggesting to be the result of habitat loss due to human development, typhoons, and persecution.

Hawaiian Crows, on the other hand, are not so lucky. Unlike Mariana Crows, who are still under protection by humans in 2021, Hawaiian Crows did not escape their fate of extinction. Before their extinction in the wild, Jon G. Giffin from Hawaii Department of Land and Natural Resources, Division of Forestry and Wildlife, Kamuela, published the article Habitat Selection and Management of the Hawaiian Crow in 1987. The article studies habitat selection of the endangered species Hawaiian Crow and the cause of their decreasing population. They made a survey of both their habitats in breeding seasons and non-breeding seasons. The result shows that Hawaiian crows nest in high-elevation areas in Moist Koa-Ohia during mating seasons, which are spring and summer, and in lower-elevation areas during non-mating seasons, which are fall and winter. The reason for the decreasing population is believed to be reduced food levels due to habitat disturbance. Some minor causes are predation on fledglings, avian disease, and human hunting (Giffin 1987).

The endangered situation of crow species can be a result of humans’ opinions towards them. Adrienne F. Sussman, Ph.D. from Department of Psychology, University of Washington Seattle, published the article Attitudes, Knowledge and Practices Affecting the Critically Endangered Mariana Crow Corvus Kubaryi and Its Conservation on Rota, Mariana Islands on Cambridge University Press with her fellow researchers. The article is about surveys she has done on residents of Rota in order to show their attitudes toward Mariana Crows. Similar to Fancy's research in 1999, Mariana Crows are still critically endangered species in 2015. Sussman made surveys and collected opinions of local citizens on the crow species. 72% thought environment issues were critical and 76% knew about the endangered situation of Mariana Crows. However, only 55% are concerned about the possible extinction of the bird, 17% thought it is okay to hunt birds, and 52% thought it is fine to chase crows. Chamorro landowners of the island are more likely to oppose Mariana Crows (Sussman 2015). Data shows that the decreasing number of Mariana Crow population can be a result of people's attitudes toward the species. In other words, when more people do not care about these birds, it's more likely to accelerate their speed of disappearing in the wild.

Potential solutions

Some researchers have noticed these problems that crows are facing. As responses to the existing problems, various solutions are provided, including artificial nest protection, captive breeding, and enhancing public education on endangered species.

Since Mariana Crows’ population is too small, it makes the species vulnerable to any predators. Any further decrease of its population can have a great effect on the whole species’ existence. In order to protect the species, one way to do so is for humans to set devices that block their habitat from their predators. Division chief of the Guam Department of Agriculture's Division of Aquatic and Wildlife Resources, Celestino F. Aguon, together with his fellow researchers, published the research article Efficacy of Electrical Barriers Used to Protect Mariana Crow Nests on Wildlife Society Bulletin. The article introduced one of the major cause of Mariana Crows to be endangered is the brown treesnake (Boiga irregularis), which is an invasive species who prey on crows' eggs. The test is conducted at Mariana Crow habitat at Guam. A platform wrapped with electric wires is placed on each test tree which are trees with Mariana Crow nests on them. Number of brown treesnakes is recorded on each test tree along with control trees without the device mounted. The result shows that zero brown treesnakes were caught on trees with electrical barriers, while 49 were caught on control trees (Aguon 2002). It is proven that electrical barriers can be effective in protecting the nests of Mariana Crows from being destroyed by ground predators, and at the same time protect the population of endangered wild Marian Crows.

However, it is also possible that since nests of Mariana Crows are isolated, they are blocked from the rest of the ecosystem. Brown treesnakes would instead prey on other species, and eco-balance can break and affect other species’ population in the long term.

Different from Mariana Crows, Hawaiian Crows have already become extinct in the wild. Luckily, before the extinction, scientists have already started the captive breeding plan. That has become the only hope to bring the species back to the wild. Philip W. Hedrick is a population geneticist and conservation biologist from the School of Life Sciences, Arizona State University. He published the article The Influence of Captive Breeding Management on Founder Representation and Inbreeding in the 'Alala, the Hawaiian Crow with other researchers in 2015. The article talks about the captive breeding strategy to prepare for the reintroduction of the already-extinct Hawaiian Crow to the wild. Wild Hawaiian Crows have been believed to be extinct since 2002. The only individuals left are the offspring of captured pairs in the 1970s. Originally, 9 individuals were captured in the wild and placed in an artificial habitat environment. Offspring of one pair from the 9 founders show high desire of breeding which the 76% of existing Hawaiian Crow population in 2014 are descendants of that pair (Hedrick 2015). The total population of Hawaiian Crows increased from 9 to the current 113 in 40 years, showing a possibility to develop a larger population and be introduced back to the wild in the future.

The captive breeding plan has a downside to it too. First of all, the ancestry population is too small, which in this case only contains nine founders. It is hard for the population to develop a genetic diversity, which by only including genetic information of those nine founders in later generations can make the species vulnerable to some disease they don’t have immunity in their genes. It is hard for the species to survive another round of natural selection. Besides, the result of the article shows a dominant pair of ancestry. The willingness to reproduce should also be taken into consideration. If some or all of the pairs are not willing to reproduce in one generation, the species can lose genes from their genetic base which already is meeting shortage. The reintroduction to the wild also needs to be considered, which is not only hard to train domestic individuals to adapt, it is also possibly going to threaten the ecosystem of the habitat region. Since the species have already vanished from the wild for decades, the ecosystem evolved and adapted to the new one without them. Reintroducing the species back can be seen as introducing an invasive species, which is going to harm the balance of the new ecosystem.

Another solution is to eliminate possible harm to the population from its source, which is to enhance education upon the species to humans living near the habitat area. Emily L. Cook and Alison A. Ormsby, both being Environmental Studies researchers from Prescott College, published the article Measuring and Developing Ecological Literacy to Conserve the Critically Endangered Mariana Crow on Applied Environmental Education & Communication in 2021. The research is about students at Mariana Island of Rota's attitudes toward and ability to identify Mariana Crow after being educated about them. Lack of knowledge about endangered species and hatred towards crows cause people to harm Mariana Crows and make their already-endangered situation even more critical. Fifth and Sixth grade students are tested on. A part of them received education about Mariana Crows and the rest of them did not. The group that received education on Mariana Crows showed a better understanding of how to identify a Mariana Crow and what they need to survive. Their attitudes toward Mariana Crows have also improved. The study result shows the possibility of protecting the wild Mariana Crow population by educating students about the species (Cook, Ormsby 2021). A longer-term education program is recommended. Below is a graph representing the result of whether the participant agrees that it is okay to chase Mariana Crows.

While there are 22 participants agreeing or strongly agreeing on the scenario, they showed a change of their attitudes after being educated, with the number of participants agreeing decreased to 0. This is by far the best solution. If we always plug the holes after a bottle starts leaking, the water inside of the bottle will be less and less, eventually reducing to a point that it dries out itself. The best way to stop water from drying out is to prevent the bottle from leaking. If the bottle never leaks, the amount of water inside will always be the same. Since the problems crows are facing majorly come from human activity, the best way to protect them is to educate others and prevent them from being harmed by people without knowledge or holding a negative attitude. If everyone agrees with not harming other species or destroying their habitat, and everyone develops a thought of protecting the natural environment and stop polluting, there will not be any problems appearing in the future that innocent animal species need to face. By educating and convincing others not to harm animals, we can bring back the beautiful planet which is friendly to all species’ survival.

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