Cock-of-the-Rock Ruckus

A male cock-of-the-rock peers at Keeper Athena.

A male cock-of-the-rock peers at Keeper Athena.

If you’ve walked through Parker Aviary at the San Diego Zoo recently, you’ve probably wondered what all the commotion is about. There has been a lot of activity as well as a lot of noise coming out of the mouths of some extravagant and brightly colored birds. At first, most seem to think that the birds are showing some aggression toward each other or are being territorial. However, there’s a different explanation for this activity, and I’d like to shed some light on it for you.

The bright reddish-orange birds with black wings and tail feathers, pale gray wing coverts (feathers on their backs), and arcing crests that extend from the back of their head to their bill, almost concealing their bill, are male Andean cocks-of-the-rock Rupicola peruvianus. The females of the species look quite different, with dull plumage that is an orange-brown color and much smaller crests. They all have strong, hooked bills and powerful legs with very sharp claws. My hands can attest to these sharp claws as I learned quickly to be extra careful when handling them. Once they get their grips on something, they won’t easily let go!

A female cock-of-the-rock gathers nesting material.

A female cock-of-the-rock gathers nesting material.

There are two species of cocks-of-the-rock: Andean and Guianan. They belong to a family of birds known as the contingas, which is an amazingly diverse neotropical family of birds containing 34 genera and 97 species. The Andean cock-of-the-rock is sometimes referred to as the national bird of Peru. The genus name Rupicola means the dweller among the rocks and explains their preferred habitat. Andean cocks-of-the-rock are found in mountainous subtropical forests of the Andes in South America, which are often close to rocky outcrops next to streams. Their diet consists of fruit, insects, and occasionally small amphibians, reptiles, and mice, which make up a significant portion of the diet that is fed to chicks.

The San Diego Zoo is proud to be home to the second largest cock-of-the-rock group in the US after the Dallas World Aquarium, where most of our birds were hatched. You can view some of them in Jungle Trails next to the Children’s Zoo as well as in the Parker Aviary. In Parker, we have six birds: four males and two females. Two of these males are housed in the walk-through side of the aviary to help simulate what happens in the wild. They participate in the display but do not participate in breeding.

One of the unique characteristics of the cock-of-the-rock occurs during breeding season: males gather at communal courtship sites known as leks where they engage in elaborate vocalization, displays, or dances. These gatherings are a form of competition for breeding females and an opportunity for the males to show off their skills. Fifteen or more males may participate in a lek.

A female observes a male cautiously.

A female observes a male cautiously.

Breeding season varies depending on the area but is prompted by the rainy season and will likely continue through February as long as they are stimulated by rain. Therefore, this is the best time of year to watch them display. As you walk through Parker Aviary, you can hear peculiar loud, hoarse grunts, chuckles, squawks, and snapping of bills as males dramatically bow, jump and flap their wings. The displays usually take place on exposed branches and occur more often early in the morning and early in the evening when the light is less intense. This may be related to the bright coloration of the males and vulnerability to predators during the display periods.

At the lek, males may be observed breaking up into pairs and performing confrontation displays. This is when most of the bowing, jumping, and bill clapping occurs, which becomes even more intense when a female approaches to investigate. The advantage of housing four males in close proximity to each other in Parker Aviary is that it provides us with the opportunity to observe these confrontation displays up close.

The female defends her nest when the male gets too close.

The female defends her nest when the male gets too close.

Following mating, the female constructs a concave cup nest of mud and vegetation. Mixing saliva with the plant matter and mud, the nest is built under a rocky overhang, in a cave, or attached to a cliff face. Occasionally, females may nest closely together if the site is suitable; however, they may also be territorial of their nest sites, as our dominant female is of her cave in Parker. A typical clutch contains 2 eggs that are incubated for 25 to 28 days. Females are solely responsible for incubation as well as chick rearing. It takes 42 to 48 days before a chick fledges. Away from lek sites, females are usually alone. Males forage in pairs, but they roost alone at night.

For now, these birds are not globally threatened. Threats in the wild include birds of prey, snakes, and encroachment on the birds’ habitat. A few fortunate visitors to places like Machu Picchu may have had the incredible opportunity to enjoy these birds in their native home. This is on my personal “to do” list. In the meantime, I will continue to enjoy working with them at the San Diego Zoo and be thankful for the privilege to experience such an incredible species. I hope you may also have this opportunity and find it equally rewarding and enlightening.

Athena Wilson is a senior keeper at the San Diego Zoo. Read her previous post, First Flamingo Hatch of 2012.

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