These are some of the most important articles I found while researching information on crows and their intelligence.
​
Sources for Literature Review of Crow Intelligence:
Heather N., Cornell, Marzluff John M., and Pecoraro Shannon. “Social Learning Spreads Knowledge about Dangerous Humans among American Crows.” Proceedings of the Royal Society B: Biological Sciences, vol. 279, no. 1728, Feb. 2012, pp. 499–508. EBSCOhost, doi:10.1098/rspb.2011.0957.
John Marzluff, wildlife scientist, and his colleagues at the University of Washington have been doing many different long-term studies on the wild crows in their campus. “Social Learning Spreads Knowledge about Dangerous Humans among American Crows,” is an extension of his previous work on crow recognition, and aims to show that information of potential dangers is passed through horizontal and vertical social learning. Their hypothesis is proven though the tracking of scolding and general reaction of the crows who were not directly captured. Over a five year period, the range of scolding has increased and the amount of scolding from uncaptured crows, as well as young crows also increased. This shows a type of social learning that crows do to spread information about potential threats, expanding upon the intelligence of the crows previously shown by Marzluff.
Wascher, Claudia, et al. “Carrion Crows Learn to Discriminate between Calls of Reliable and Unreliable Conspecifics.” Animal Cognition, vol. 18, no. 5, Sept. 2015, pp. 1181–1185. EBSCOhost, doi:10.1007/s10071-015-0879-8.
Wascher, animal behavior researcher, and her colleagues at Anglia Ruskin University in Cambridge, England wrote “Carrion Crows Learn to Discriminate between Calls of Reliable and Unreliable Conspecifics,” as an expansion of a line of similar tests done on many different animals. The goal was to analyze whether or not crows could differentiate "reliable" and "unreliable" calls by showing certain groups of crows a "dead" conspecific, allowing them to hear their calls and monitor their reactions. The results showed a clear distinction showed by the crows between hearing the call of the "reliable" versus "unreliable" source. This reveals a sense of self-awareness and "trust" between crows that is required from animals with complex social structures, similar to humans.
Hillemann, Friederike, et al. “Waiting for Better, Not for More: Corvids Respond to Quality in Two Delay Maintenance Tasks.” Animal Behaviour, vol. 90, Apr. 2014, pp. 1–10. EBSCOhost, doi:10.1016/j.anbehav.2014.01.007.
Hillemann, behavioral ecologist, and researchers of Max Planck Institute for Evolutionary Anthropology wrote “Waiting for Better, Not for More: Corvids Respond to Quality in Two Delay Maintenance Tasks” in order to test a crow's ability to control impulses. Through the test, the crows traded for a higher quality food item at the cost of waiting. This proved successful, as one crow was willing to wait over ten minutes to trade. This impulse control is an important tracker of intelligence and ability in animals. The crows were concluded to have made conscious decisions as while they traded for higher quality items, they did not trade for increased quantities.
​
​
Here are 3 articles the clearly outline some problems that birds face.
​
Loss, Scott R., et al. “Bird–Building Collisions in the United States: Estimates of Annual Mortality and Species Vulnerability.” The Condor, vol. 116, no. 1, 2014, pp. 8–23., doi:10.1650/condor-13-090.1.
Scott Loss is a wildlife ecologist acting as an assistant professor at Oklahoma State University. He wrote “Bird–Building Collisions in the United States: Estimates of Annual Mortality and Species Vulnerability” to find quantitative evidence of mortality rates of birds through collisions. What he found was that there were approximately 100 million to 1 billion bird deaths each year due to building collisions. This is second only to cat mortalities, which account for around 4 times as many deaths.
​
Runwal, Priyanka, and July 09. “Building Collisions Are a Greater Danger for Some Birds Than Others.” Audubon, 9 Apr. 2021, www.audubon.org/news/building-collisions-are-greater-danger-some-birds-others
Written by Priyanka Runwal, a freelance journalist, and published in the Audubon
Magazine. “Building Collisions Are a Greater Danger for Some Birds Than Others.” was written to talk about the death tolls buildings have on birds, especially small migratory birds. Luckily she also talks about some solutions that are being done such as the bird-safe buildings act.
​
Gross, Rachel E. “The Moral Cost of Cats.” Smithsonian.com, Smithsonian Institution, 20 Sept. 2016, www.smithsonianmag.com/science-nature/moral-cost-of-cats-180960505/.
Rachel Gross is a famous science writer working for the Smithsonian Magazine, but also appearing in The New York Times, National Geographic, and WIRED. In "The Moral Cost of Cats" Gross goes over the great affect cats have had on bird populations and how scientists are trying to rein in the cats and keep them indoors. Interviewing different scientists, many estimated cats to the cause of death for around 12 billion small animals. Ultimately, she concluded that not much is being done for they fact cats are able to kill many small pests such as rats, and that they are a beloved pet. However, this is at the cost of many endangered bird and other animal species.
​
​
Some Examples of Solutions and What You can do
​
“Legislation, Ordinances, & Code.” American Bird Conservancy, 13 Jan. 2021, abcbirds.org/glass-collisions/legislation/.
The American Bird Conservancy is a national organization that aims to solve problems for birds through both legislation as well as grassroots methods. On this page from their website you can find information on what is being done in ways of legislation to support birds. Specifically the "Bird-friendly" building guidelines and glass.
​
Society, National Audubon, and May 06. “Biden Administration Moves One Step Closer to Reinstating Migratory Bird Protections.” Audubon, 6 May 2021, www.audubon.org/news/biden-administration-moves-one-step-closer-reinstating-migratory-bird.
The Audubon Society works similarly to The American Bird Conservancy, as a national organization trying to lobby for national legislation. However, The Audubon Society also has a magazine, meant to spread the love of birds and information on dangers. This article talks about the actions the Biden Administration is taking to rollback the changes President Trump did to the Migratory Bird Treaty Act. This will reinstall the protections for birds and punish the killing of these endangered animals.
​
“Take Action.” American Bird Conservancy, 10 Nov. 2020, abcbirds.org/program/cats-indoors/take-action/.
The American Bird Conservancy advocates people to be more active in their participation. Their website has a lot of different problems outlined, which you can support by signing. This link will send you to the "cats indoors" pledge. In order to prevent more unnecessary cat-bird killings, you will pledge to keep you cats indoors and do your part in solving the problem.