Songs of Isolation?

By Pyper, Wendy | Ecos, July-September 2000 | Go to article overview

Songs of Isolation?


Pyper, Wendy, Ecos


The songs of upland bowerbirds vary uniquely from place to place and are as culturally distinct from one another as regional dialects or languages are to humans.

In the cool rainforests of Queensland's tropical north, an evolution in communication is under way. The songs of birds, restricted to these `upland' forests for millennia, have provided the first evidence that the geographic isolation of bird populations can promote song variation within species. The discovery, by David Westcott and his colleagues from the CSIRO Tropical Forest Research Centre and the CRC for Tropical Rainforest Ecology, has its origins in climatic history.

About 7500 years ago, cool rainforest covered much of the wet tropics region. But a period of warming, between 2000 and 5000 years ago, saw these cool rainforests contract to upland areas, about 600 metres above sea level, while warmer forest types dominated lower areas. As the cool rainforests contracted, so did the habitat of many species of birds, including the golden bowerbird, the fernwren and the mountain thornbill. This contraction fragmented the birds' habitat and saw populations of these endemic species split and become isolated: a process biogeographers call `vicariance'.

Today, 13 bird species are endemic to the upland rainforests of the wet tropics, and exist in isolated populations between Cook Town and Townsville. What Westcott and his colleagues wanted to know, was whether this isolation (vicariance) had affected the birds, and, if so, how.

Birdsong is thought to evolve through a number of selective forces, such as natural selection (environmental pressure), sexual or social selection, and drift (vagaries of the learning process). So Westcott suspected that vicariance could play a role in promoting song variation among birds of the same species.

To test this theory, he recorded the songs of seven upland bird species and seven species of `altitudinal generalists' -- birds distributed across the upland and lowland regions -- in seven rainforest blocks between Cook Town and Townsville.

He then analysed the 578 recorded songs using computer software that allowed him to measure a range of variables in song structure. …

The rest of this article is only available to active members of Questia

Already a member? Log in now.

Notes for this article

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
One moment ...
Default project is now your active project.
Project items

Items saved from this article

This article has been saved
Highlights (0)
Some of your highlights are legacy items.

Highlights saved before July 30, 2012 will not be displayed on their respective source pages.

You can easily re-create the highlights by opening the book page or article, selecting the text, and clicking “Highlight.”

Citations (0)
Some of your citations are legacy items.

Any citation created before July 30, 2012 will labeled as a “Cited page.” New citations will be saved as cited passages, pages or articles.

We also added the ability to view new citations from your projects or the book or article where you created them.

Notes (0)
Bookmarks (0)

You have no saved items from this article

Project items include:
  • Saved book/article
  • Highlights
  • Quotes/citations
  • Notes
  • Bookmarks
Notes
Cite this article

Cited article

Style
Citations are available only to our active members.
Buy instant access to cite pages or passages in MLA, APA and Chicago citation styles.

(Einhorn, 1992, p. 25)

(Einhorn 25)

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Cited article

Songs of Isolation?
Settings

Settings

Typeface
Text size Smaller Larger Reset View mode
Search within

Search within this article

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

Help
Full screen

matching results for page

    Questia reader help

    How to highlight and cite specific passages

    1. Click or tap the first word you want to select.
    2. Click or tap the last word you want to select, and you’ll see everything in between get selected.
    3. You’ll then get a menu of options like creating a highlight or a citation from that passage of text.

    OK, got it!

    Cited passage

    Style
    Citations are available only to our active members.
    Buy instant access to cite pages or passages in MLA, APA and Chicago citation styles.

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn, 1992, p. 25).

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences."1

    1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

    Cited passage

    Thanks for trying Questia!

    Please continue trying out our research tools, but please note, full functionality is available only to our active members.

    Your work will be lost once you leave this Web page.

    Buy instant access to save your work.

    Already a member? Log in now.

    Oops!

    An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.