How are Brown-headed Cowbirds and Cuckoo Birds Nest
Parasites?
By: Sophie Tatar, '20
(CHAOS 2017 EDITION)
(CHAOS 2017 EDITION)
Early one morning, a cuckoo bird swoops into a bluebird’s small nest, as she is gone collecting worms. Upon the bluebird’s return, she finds an egg that does not seem to be hers. Even though this is not her egg, she raises the egg as her own, due to the birth mother’s abandonment. Cuckoo birds (Cuculus canorus) and other types of birds such as Brown-headed Cowbirds (Molothrus ater) are considered brood parasites, commonly known as nest parasites. They lay their eggs in other birds’ nests, and then leave. The Cuckoo bird and the Brown-headed Cowbird “infest” as many as 220 different species of birds.
Miraculously, the host bird is able to accept the new egg as one of it’s own. According to an article titled, “Of Cuckoos, Cowbirds, and Other Parasitic Birds”, by Sarah Zielinski, Cuckoo birds are able to choose host species with eggs similar to their own egg shape, size and color.Also, in order to make the host accept the parasitic egg, the mother Brown-headed Cowbird pushes one of the original eggs out of the nest. This way, the original number of eggs remains, and the host bird does not reject the parasitic egg.
Despite being raised by a different species than their own, the young Cowbirds show characteristics of their own species as young as one month old. At about 20-25 days old, a Cowbird’s first instinct is to roost, or settle, in a field for the night, only to return to the host’s nest the next day. This field is where most of the other Cowbirds live. This allows the bird to mingle, and learn the behaviors of its own species.
This cycle of life is a major advantage for the brood parasites because they don’t have to invest any energy and time into raising their young. However, this also takes a toll on the host species. Since the Brown-headed Cowbirds are not native to North America, the birds native to our continent are disappearing. Possibly due to their larger size, the parasitic birds require more food and space than the host species do. The Brown-headed cowbird risks killing off some of the young of its host species. If the species slowly dies out, then the parasitic bird will have no foster nest to lay its egg, creating an unbalance in nature.
Cuckoo birds and Brown-headed Cowbirds are not the only type of parasites in our ecosystem. Some parasites affect humans! Some endoparasites, which are parasites that live internally within the host’s body, include salmonella, tapeworm, and E.coli. These pathogens, usually associated with the digestive system, can cause mild to severe gastrointestinal disease, and unfortunately, sometimes even death of the host. This is an example of an antipathic relationship. To avoid this result, we should make our best efforts to consume fully cooked meats and eggs, wash our hands after using raw contaminated foods, and practice good hygiene.
Cuckoo birds, Brown-headed Cowbirds, and many other species of brood parasites are examples of strange but successful relationships in the animal kingdom. It is amazing how birds are not able to recognize their own egg apart from an imposter. Take a look around at birds in your neighborhood. You might just be a witness to a brood parasite taking advantage of a host’s nest. In the animal world, it’s nothing personal, just business as usual.
Miraculously, the host bird is able to accept the new egg as one of it’s own. According to an article titled, “Of Cuckoos, Cowbirds, and Other Parasitic Birds”, by Sarah Zielinski, Cuckoo birds are able to choose host species with eggs similar to their own egg shape, size and color.Also, in order to make the host accept the parasitic egg, the mother Brown-headed Cowbird pushes one of the original eggs out of the nest. This way, the original number of eggs remains, and the host bird does not reject the parasitic egg.
Despite being raised by a different species than their own, the young Cowbirds show characteristics of their own species as young as one month old. At about 20-25 days old, a Cowbird’s first instinct is to roost, or settle, in a field for the night, only to return to the host’s nest the next day. This field is where most of the other Cowbirds live. This allows the bird to mingle, and learn the behaviors of its own species.
This cycle of life is a major advantage for the brood parasites because they don’t have to invest any energy and time into raising their young. However, this also takes a toll on the host species. Since the Brown-headed Cowbirds are not native to North America, the birds native to our continent are disappearing. Possibly due to their larger size, the parasitic birds require more food and space than the host species do. The Brown-headed cowbird risks killing off some of the young of its host species. If the species slowly dies out, then the parasitic bird will have no foster nest to lay its egg, creating an unbalance in nature.
Cuckoo birds and Brown-headed Cowbirds are not the only type of parasites in our ecosystem. Some parasites affect humans! Some endoparasites, which are parasites that live internally within the host’s body, include salmonella, tapeworm, and E.coli. These pathogens, usually associated with the digestive system, can cause mild to severe gastrointestinal disease, and unfortunately, sometimes even death of the host. This is an example of an antipathic relationship. To avoid this result, we should make our best efforts to consume fully cooked meats and eggs, wash our hands after using raw contaminated foods, and practice good hygiene.
Cuckoo birds, Brown-headed Cowbirds, and many other species of brood parasites are examples of strange but successful relationships in the animal kingdom. It is amazing how birds are not able to recognize their own egg apart from an imposter. Take a look around at birds in your neighborhood. You might just be a witness to a brood parasite taking advantage of a host’s nest. In the animal world, it’s nothing personal, just business as usual.
Works Cited:
Comments on: Brown-headed Cowbirds - NestWatch. (2011). Retrieved November 5, 2016, from http://nestwatch.org/learn/general-bird-nest-info/brown-headed-cowbirds/
How Does a Cowbird Learn To Be a Cowbird? | Audubon. (n.d.). Retrieved from http://www.audubon.org/news/how-does-cowbird-learn-be-cowbird
BioKIDS - Kids' Inquiry of Diverse Species, Molothrus ater, brown-headed cowbird: INFORMATION. (n.d.). Retrieved from http://www.biokids.umich.edu/critters/Molothrus_ater/
Zienlinski, S. (2013). Wild Things. Retrieved from http://wildthings.sarahzielinski.com/blog/of-cuckoos-cowbirds-and-other-parasitic-birds/
"Parasitism." Home. N.p., n.d. Web. 22 Jan. 2017. Retrieved from
http://www.colorado.edu/eeb/courses/2040bowman/EBIO2040/Syllabus_files/018.html
Comments on: Brown-headed Cowbirds - NestWatch. (2011). Retrieved November 5, 2016, from http://nestwatch.org/learn/general-bird-nest-info/brown-headed-cowbirds/
How Does a Cowbird Learn To Be a Cowbird? | Audubon. (n.d.). Retrieved from http://www.audubon.org/news/how-does-cowbird-learn-be-cowbird
BioKIDS - Kids' Inquiry of Diverse Species, Molothrus ater, brown-headed cowbird: INFORMATION. (n.d.). Retrieved from http://www.biokids.umich.edu/critters/Molothrus_ater/
Zienlinski, S. (2013). Wild Things. Retrieved from http://wildthings.sarahzielinski.com/blog/of-cuckoos-cowbirds-and-other-parasitic-birds/
"Parasitism." Home. N.p., n.d. Web. 22 Jan. 2017. Retrieved from
http://www.colorado.edu/eeb/courses/2040bowman/EBIO2040/Syllabus_files/018.html