Screamers: Social Structure

Summary: Do Screamers hang out with other Screamers? That depend on the specs. Join Kiersten to find out a little about the social structure of each species of Screamer.

 

For my hearing impaired followers, a complete transcript of this podcast follows the show notes on Podbean

 

Show Notes:

“Aspects of the Biology of the Horned Screamer in Southwestern Colombia,” by Luis G. Naranjo. The Wilson Bulletin, Vol. 98, No. 2 (June, 1986, pp. 243-256

“Mortality of four captive-born crested screamer chicks (Chauan torquata)”, by Lana Fox, Alexis Moreno, and Gregory Bradley. Open Veterinary Journal, 2019 Apr 28:;9(2):120-125. Doi:10.4314/ovj.v9i2.5

Screamers: https://animaldiversity.org

Music written and performed by Katherine Camp

 

Transcript

(Piano music plays)

Kiersten - This is Ten Things I Like About…a ten minute, ten episode podcast about unknown or misunderstood wildlife.

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Welcome to Ten Things I Like About… I’m Kiersten, your host, and this is a podcast about misunderstood or unknown creatures in nature. Some we’ll find right out side our doors and some are continents away but all are fascinating. 

This podcast will focus ten, ten minute episodes on different animals and their amazing characteristics. Please join me on this extraordinary journey, you won’t regret it.

This is episode four of screamers and the fourth thing I like about Screamers is their social structure. As we have learned previously, there are three species of screamers. Each species is found in a different range of South America, but they reside in similar habitats and eat similar diets. Their coloration is slightly different which does help in identification once you have those differences memorized. Interestingly these three species that are alike is so many ways have different social structures.

Let’s start off with the Northern Screamer, also known as the Black-necked Screamer, Chauna chavaria, This screamer is found across northern Columbia from the Atrato River and Magdalena River valleys east into the Lake Maracaibo area of Venezuela. They are most often found near water in habitats such as swamps, marshes, lagoons, riverbanks, and seasonally flooded river plains. They are a non-migratory species, so remain in the same area year round.

The social structure of the Northern Screamer seems to revolve around the mated pair. Once a pair bond is established, that couple remains together and defends a territory year around. The pair mates for life or an extended period of time. Since they are a bit anti-social when it comes to entertaining other Northern Screamer neighbors, their social structure is fairly simple. They live in small familial groups consisting of the mated pair and their offspring. 

I found very few research papers doing in-depth studies into this species social structure but based on other species that remain in familial groups, once the offspring are old enough to reproduce they leave the parents’ territory to find their own mate and establish their own territory, or are run off by the parents to find their own mate and establish their own territory. An educated guess dictates that this is the behavior the Northern Screamers follow, as well. To remain genetically diverse and produce healthy offspring, you gotta leave home.

Let’s travel south and visit with the Southern Screamer, also known as the Crested Screamer, Chauna torquata. They are found from the eastern half of Bolivia south into Argentina as far as Buenos Ares Province and east through Paraguay into south western Brazil and Uruguay. 

Southern Screamers prefer tropical and subtropical wetlands including lakes, marshes, and flooded meadows with scattered trees. They are permanent residents wherever they are found.

The social structure of the Southern Screamer varies depending on the season. During breeding season, mated pairs are extremely territorial and will defend their established area fiercelyincluding using the spurs on their wings to fight off intruding screamers or other animals. In the off season, Southern  Screamers are the most gregarious of all the screamer species. They gather together in groups of up to 1500 individuals.

This species seems to have the closest relationship to humans. These large groups are often seen foraging near livestock. This may have something to do with them gathering in larger groups. It may be a safety in numbers situation, or it could simply be an abundance of resources available in their region. Whatever the reason, the Southern Screamer is definitely the most gregarious screamer of all three species.

The third species of screamer is the Horned Screamer, Anhima cornuta. The range of the Horned Screamer is much larger than our other two species and includes the Amazonian regions of Venezuela, to the eastern llanos of Columbia, to eastern Bolivia and south-central Brazil. Habitat frequented by these birds include tropical lowland freshwater areas such as lakes, ponds, rivers, marshes, and swamps.

Just like the other screamer species, Horned Screamers are permanent residents of their ranges and appear to defend territories year round. Mated pairs will bond for life and both parties participate in defending the territory. Some studies indicate that Horned Screamers live in smaller groups for longer periods of time than other species. These groups may not be related because mated males have been seen driving off their male offspring when they tried to court the female mate, which is the juvenile’s mother. 

Mated pairs that remain in the same territory do not nest near each other so as not to encroach on each others resources, but sharing the responsibility of defending a larger territory can be advantageous to their survival. 

I find it so interesting that three species of bird that are so similar in almost all aspects of their lives can have such diverse social structures. This episode is a bit shorter than most but we have a lot more to learn about the social structure of all the Screamer species. I hope someone out there listening to this podcast is inspired to jump into this subject so we can all learn more about the social structure of this species because it’s my fourth favorite thing about screamers.

If you're enjoying this podcast please recommend me to friends and family and take a moment to give me a rating on whatever platform your listening. It will help me reach more listeners and give the animals I talk about an even better chance at change. 

Join me next week for another exciting episode about Screamers.  

    

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This has been an episode of Ten Things I like About with Kiersten and Company. Original music written and performed by Katherine Camp, piano extraordinaire.