Featured Research

from universities, journals, and other organizations

Cuckoos impersonate hawks by matching their 'outfits'

Date:
October 16, 2013
Source:
University of Cambridge
Summary:
An evolutionary trick allows cuckoos to 'mimic' the plumage of birds of prey, and may be used to scare mothers from their nests -- allowing cuckoos to lay eggs. Parasitism in cuckoos may be more much more widespread than previously thought.

New research shows that cuckoos have striped or "barred" feathers that resemble local birds of prey, such as sparrowhawks, that may be used to frighten birds into briefly fleeing their nest in order to lay their parasitic eggs.
Credit: Thanh-Lan Gluckman and Gabriel A. Jamie

New research shows that cuckoos have striped or "barred" feathers that resemble local birds of prey, such as sparrowhawks, that may be used to frighten birds into briefly fleeing their nest in order to lay their parasitic eggs.

By using the latest digital image analysis techniques, and accounting for "bird vision" -- by converting images to the spectral sensitivity of birds -- researchers have been able to show for the first time that the barred patterns on a cuckoo's breast may allow it to impersonate dangerous birds of prey. This might enable cuckoos to frighten other avian hosts into leaving their nests exposed.

The latest findings, published today in the journal Animal Behaviour, expand the cuckoo's arsenal of evolutionary deceptions, which include egg mimicry and chick mimicry that allow it to trick other birds into incubating its eggs.

Importantly, the study shows that a wide variety of cuckoos have adapted different plumage patterns depending on the area they inhabit so that they match a local bird of prey species.

While scientists have intensively researched links in plumage patterns between the common cuckoo and Eurasian sparrowhawk, the new research shows that this type of impersonation of a more dangerous animal -- called 'Batesian mimicry' -- may be far more widespread in cuckoos. In addition, the dangerous bird of prey that cuckoos resemble goes beyond sparrowhawks to include such raptors as bazas and harrier-hawks -- depending on the species prevalent in the cuckoo's neighbourhood.

"There is no benefit in looking like a dangerous species your target is not familiar with," said lead researcher Thanh-Lan Gluckman from Cambridge's Department of Zoology.

"We first established similarity in plumage pattern attributes between cuckoos and raptor species, and then showed that cuckoos look nothing like species from a different geographical area."

The cuckoos also use their crafty 'hawk impression' to allow them to fly 'under the radar', undetected as they scope out potential nests in which to deposit their parasitic eggs.

"The barring on their plumage helps cuckoos conceal themselves while searching for potential nests, then when they approach, the host of the nest may mistake a cuckoo for a raptor coming to get them -- giving them unfettered access to lay eggs," Gluckman said.

While previous studies have focused on Batesian mimicry in the common cuckoo and Eurasian sparrowhawk, this is the first time that the plumage patterns of cuckoos have been analysed using digital image analysis techniques. The study suggests that this form of mimicry may be widespread among many cuckoo species, and that they may be mimicking a variety of different types of birds of prey.

The researchers were "surprised" to find no pattern matching between cuckoos and raptors that live in different geographical areas, showing that the visual similarity is highly localised to species in the immediate vicinity.

"These findings underscore the importance of using digital image analysis to objectively quantify plumage patterning in mimicry -- it is important not to make assumptions about even simple patterns such as these," added Gluckman.

"We hope this encourages other researchers to examine the function of barred plumage in parasitic cuckoos and raptors the world over."

Another interesting finding is that of the African cuckoo-hawk, a raptor so named because of its visual resemblance to cuckoos. This study objectively shows that the naming was an apt one, given that a local cuckoo matched the African cuckoo-hawk in all of the pattern attributes measured.

One of the earliest observers of the cuckoos' invasive guile was Ancient Greek philosopher Aristotle, who noted some 2,300 years ago that it "lays its eggs in the nest of smaller birds."


Story Source:

The above story is based on materials provided by University of Cambridge. Note: Materials may be edited for content and length.


Journal Reference:

  1. Thanh-Lan Gluckman, Nicholas I. Mundy. Cuckoos in raptors' clothing: barred plumage illuminates a fundamental principle of Batesian mimicry. Animal Behaviour, 2013; DOI: 10.1016/j.anbehav.2013.09.020

Cite This Page:

University of Cambridge. "Cuckoos impersonate hawks by matching their 'outfits'." ScienceDaily. ScienceDaily, 16 October 2013. <www.sciencedaily.com/releases/2013/10/131016112704.htm>.
University of Cambridge. (2013, October 16). Cuckoos impersonate hawks by matching their 'outfits'. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2013/10/131016112704.htm
University of Cambridge. "Cuckoos impersonate hawks by matching their 'outfits'." ScienceDaily. www.sciencedaily.com/releases/2013/10/131016112704.htm (accessed July 31, 2014).

Share This




More Plants & Animals News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Thousands Flocking to German Crop Circle

Raw: Thousands Flocking to German Crop Circle

AP (July 30, 2014) Thousands of people are trekking to a Bavarian farmer's field to check out a mysterious set of crop circles. (July 30) Video provided by AP
Powered by NewsLook.com
Concern Grows Over Worsening Ebola Crisis

Concern Grows Over Worsening Ebola Crisis

AFP (July 30, 2014) Pan-African airline ASKY has suspended all flights to and from the capitals of Liberia and Sierra Leone amid the worsening Ebola health crisis, which has so far caused 672 deaths in Guinea, Liberia and Sierra Leone. Duration: 00:43 Video provided by AFP
Powered by NewsLook.com
At Least 20 Chikungunya Cases in New Jersey

At Least 20 Chikungunya Cases in New Jersey

AP (July 30, 2014) At least 20 New Jersey residents have tested positive for chikungunya, a mosquito-borne virus that has spread through the Caribbean. (July 30) Video provided by AP
Powered by NewsLook.com
Xtreme Eating: Your Daily Caloric Intake All On One Plate

Xtreme Eating: Your Daily Caloric Intake All On One Plate

Newsy (July 30, 2014) The Center for Science in the Public Interest released its 2014 list of single meals with whopping calorie counts. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

    Environment News

    Technology News



      Save/Print:
      Share:

      Free Subscriptions


      Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

      Get Social & Mobile


      Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

      Have Feedback?


      Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
      Mobile: iPhone Android Web
      Follow: Facebook Twitter Google+
      Subscribe: RSS Feeds Email Newsletters
      Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins