1 Burnie, David. 2008. Bird. New York, NY: DK Publishing.
2 Castro, Joseph. "Grudge-Holding Crows Pass on Their Anger to Family and Friends." Discover. June 30, 2011. Accessed: October 20 2019.
3 Chakraborty, Barnini. “Feds Look Other Way as Wind Farms Kill Birds? But Haul Oil and Gas Firms to Court.” Fox News. December 17, 2012. Accessed: March 22, 2013.
4 Cota-Larson, Rhishja. "16 Things You May Not Know about Vultures." Annamiticus. August 27, 2012.&n
5 "Esmeraldas Woodstar." Center for Biological Diversity. Accessed: September 7, 2019.
6 "Falcon." Online Etymology Dictionary. Accessed: January 5, 2017.
7 "Fear of Ducks Phobia – Anatidaephobia." FearOf.Net. Accessed: December 26, 2016.
8 Jacabo, Julia. "Two-thirds of birds in North America at risk of extinction due to climate change." October 10, 2019. Accessed: October 15, 2019.
9 Mayell, Hillary. “Evolutionary Oddities: Duck Sex Organ, Lizard Tongue.” National Geographic. October 23, 2001. Accessed: March 22, 2013.
10 Miller, Sara Swan. 2001. Bizarre Birds. New York, NY: Watts Library.
11 Molly, Mark. "The Ultimate True Or False Quiz: Scientific Fact Or Fiction?" The Telegraph. April 22, 2016. Accessed: December 6, 2016.
12 Munford, Monty. “Angry Birds: 10 Things You Probably Didn’t Know.” The Telegraph. October 12, 2010. Accessed: March 22, 2013.
13 Netter, Sarah. “Birds Hit Planes Every Day, but Don’t Usually Cause Crashes.” ABC News. January 15, 2009. Accessed: March 22, 2013.
14 "Parakeet." Petco. Accessed: July 23, 2018.
15 Penny, Malcolm. 2000. Birds: Over 100 Questions and Answers to Things You Want to Know. Suffolk, UK: Dempsey Parr.
16 Raasch, Chuck. “Cats Kill Up to 3.7B Birds Annually.” USA Today. January 30, 2013. Accessed: March 22, 2013.
17 Snedden, Robert. 2008. Birds (Living Things). North Mankato, MN: Smart Apple Media.
18 "Swan." Online Etymology Dictionary. Accessed: August 7, 2019.
19 “The Birds (1963).” IMBD. Accessed: March 22, 2013.
20 “Woodpeckers.” Cornell Lab of Ornithology. 2002. Accessed: March 22, 2013.