Reproduction

Raised by Others, Birds Use Code to Find Their Kind

Publication: National Geographic News   Date: October 15, 2004   View Article

Reproduction success hinges on several factors, not least of which is finding a mate within the same species. While this is an easy enough task for humans, it is seemingly more complicated for brown-headed cowbirds (Molothrus ater).

The animals are one of the more than 90 known parasitic bird species, so called because they lay their eggs in the nests of other bird species and leave the chick-rearing to other parents.

Can Captive Breeding Rescue Vultures from Extinction?

Publication: National Geographic News   Date: May 11, 2004   View Article

Twenty to 30 years of captivity is the only option left to save three species of south Asian vultures from extinction, according to conservationists who are racing against time to get enough birds into safekeeping.

Over the past decade populations of the Asian white-backed vulture (Gyps bengalensis), long-billed vulture (Gyps indicus), and slender-billed vulture (Gyps tenuirostris) have declined by more than 95 percent in Pakistan, India, and Nepal.

Finding a Valentine Can Be Hard for Animals Too, Cameras Show

Publication: National Geographic News   Date: February 12, 2004   View Article

For National Geographic researchers, it’s all in the name of science, but a camera-equipped system they developed to deploy on wild animals has a certain voyeuristic quality to it.

The research tool, known as Crittercam, has been carried by all kinds of male marine mammals trying to woo their female counterparts. In a seeming testament to the plight of males throughout the animal kingdom, the Crittercam footage shows that getting a female to mate is a tough task.

Cockerels Dole Sperm With Precision, Study Says

Publication: National Geographic News   Date: November 5, 2003   View Article

When it comes to the primal urge to pass genes on to the next generation, red jungle fowls (Gallus gallus) are a sophisticated lot: They dole out their sperm with economic and strategic precision, according to a new study.

Like most species in the animal kingdom, the birds (a type of wild chicken) are sexually promiscuous. Females may mate with several different males in any given reproductive cycle. Males seem to mate whenever they get a chance.

Female Moa Birds Liked the Little Guys, Studies Suggest

Publication: National Geographic News   Date: September 11, 2003   View Article

Female moa birds had a sweet spot for the little guys, according to two papers appearing in the September 11 issue of Nature.

The research teams, led by scientists in New Zealand and England, applied a pioneering technique in genetic analysis that allowed them to determine the sex of extinct moa by analyzing nuclear DNA extracted from fossils.

Rare Antelope on Brink of Extinction, Scientists Say

Publication: National Geographic News   Date: April 25, 2003   View Article

Male saiga antelopes face a serious problem that threatens to push them over the brink of extinction: so many females, so little time.

The global population of this antelope, native to the steppes and deserts of Central Asia and the Pre-Caspian region of Europe, has fallen by 80 percent to approximately 50,000. In the mid-1970s, the peak population was more than 1,250,000. Of the saiga antelopes that remain, most are female.

Are Flashy Male Birds Threats to Their Own Species?

Publication: National Geographic News   Date: April 8, 2003   View Article

For bird species whose males and females differ in color, guys with the brightest feathers tend to have the greatest lady luck. This natural mating game however puts entire local populations at risk of dying out, according to a new study.

The finding confirms the idea that the extraordinary lengths an animal will go to woo a mate, such as the peacock who spends time and energy to maintain his extravagant tail feathers, comes at a price in terms of survival.

© 2008-2010 Collected Writings By John Roach