And that, perhaps, explains why hummingbirds as a group have evolved female-limited polymorphism so often—for, of all known vertebrates, they have the highest metabolic demand per gram of body ...

Most birds don't have external genitalia and mate by rubbing an opening called the cloaca, which is present in both males and females, against another bird's cloaca.

Scientists just recently decided to study female birds. What they found astounded them. Some female birds, like the two red-legged honeycreepers (Cyanerpes cyaneus) pictured above in Costa Rica ...

Scientists have found that although male and female birds have an almost identical set of genes, they function differently in each sex through a mechanism called alternative splicing.

All-Female Expedition In December of 2020, Garzon was invited to be part of a five woman expedition called "BIO: wings, songs and colors." ...

This bi-colored northern cardinal has female plumage on its right, and male plumage on its left. Called a “gynandromorph,” these animals are rare in nature. Rarer still is the chance to study ...

Bird song is commonly seen as a male trait that plays a role in female attraction, but its origin and prevalence in females are unknown. Here, Odom et al.show that female song is widespread and ...

Among birds, females often rule the roost. Not only do females frequently take control in the selection of a mate and over nesting activities, but several female birds also are larger and more ...

The bird was identified as a Rose-breasted Grosbeak. Male and female Grosbeaks are distinguished by their color: males have pink “wing pits,” while females are yellow-brown. The sides of this ...

Researchers at the Powdermill Nature Reserve in Pennsylvania were thrilled to be visited recently by a half male, half female rose-breasted grosbeak.

Now, researchers have found that female birds make a similar sacrifice when colouring their eggs, creating vivid hues at the expense of their health.

Researchers at Powdermill Nature Reserve near Pittsburgh spotted a bird with pink male coloring on half of its body and yellow female hues on the other.