Birds of prey, also known as raptors, include hawks, eagles, owls, vultures, and falcons. These birds typically have excellent eyesight, powerful talons, and curved beaks adapted for tearing flesh. One distinctive feature many birds of prey possess is a hood or cowl of feathers on their head. But what exactly is this specialized plumage called?
What is the Hood on a Bird of Prey’s Head Called?
The hood or cowl of feathers on a bird of prey’s head is called a cere. The cere is a fleshy structure that covers the base of the beak and nostrils. It is typically brightly colored or patterned and serves multiple functions for raptors.
Some key facts about the cere:
- The cere helps regulate respiration and protects the nostrils.
- In some species, the cere may help raptors sense chemical signals.
- The cere can aid thermoregulation, preventing the beak from overheating in strong sunlight.
- The colorful cere may play a role in mating displays and communication.
- The size and shape of the cere can help identify different raptor species.
The cere comes in a variety of colors and patterns depending on the species. For example, the peregrine falcon has a blue-gray cere while the red-tailed hawk has a yellow cere. The cere may also change color during breeding season.
Anatomy and Function of the Cere
The cere consists of a layer of soft tissue that covers the bony base of the upper beak. It encircles the nostrils and extends down to surround the top of the beak. The fleshy tissue is made up of a dense network of blood vessels and contains sensory receptors.
Thermoregulation
One of the cere’s functions is to help regulate beak temperature. Raptors use their beaks to tear apart prey, so they are susceptible to overheating. The cere’s fleshy covering prevents the beak from getting too hot in strong sunlight. The increased blood flow to the cere also helps dissipate heat.
Respiration
In addition to temperature regulation, the cere plays an important role in respiration. The cere surrounds the external nares (nostril openings) and helps direct airflow across the nasal passages. This allows birds to breathe while keeping their beaks shut. The cere’s shape influences how air currents move through the nostrils during both inhalation and exhalation.
Sensory Perception
The cere also contains sensory nerve endings that may help some raptors detect chemical signals. Species like vultures have a highly developed sense of smell thanks to their extensive cere tissue. Vultures can detect scent particles dissolved in air currents flowing over their cere. This aids them in locating carrion from great distances away.
Communication and Displays
The conspicuous colors and patterns of the cere likely play a role in visual communication. The cere’s colors may help signal a raptor’s mood or broadcast its breeding status to potential mates. Some species will also fluff out their cere feathers as part of courtship rituals and territorial displays.
Variations in Cere Size, Shape, and Color
The cere comes in different sizes, shapes, textures, and colors among the various raptor species. Here are some examples:
Owls
Owls tend to have a flat or heart-shaped facial disk of feathers surrounding their eyes and cere. Most owls have a grayish or brown cere, but some species like the barn owl have a distinctive heart-shaped white or pinkish cere.
Eagles
Eagles have a large protruding cere at the top of their sharp beaks. The cere is typically yellow or gray-yellow. Bald eagles have a yellow cere while golden eagles have a golden yellow cere.
Falcons
Falcons have a rounded cere encircling their nostrils. Their cere ranges from blue-gray to red, yellow, or orange. Peregrine falcons have a bluish cere with yellow accents around the nostrils.
Hawks
Hawks have a prominently curved beak tipped with a yellow, orange, gray or white cere. The cere is well-defined on some species like the red-tailed hawk. Other hawk species like the Cooper’s hawk have a smaller, less noticeable cere.
Vultures
Vultures have a large cere that extends down around their nostrils. The cere is typically gray, yellow, orange, or red. Turkey vultures have a bright red cere while the Andean condor has a yellow cere.
The Cere of Common North American Raptors
Here is a breakdown of the cere type for some of the most common hawks, eagles, falcons, and owls found across North America:
Red-Tailed Hawk
- Cere Color: Yellow
- Cere Shape: Rounded and prominent
Cooper’s Hawk
- Cere Color: Yellow-Orange
- Cere Shape: Smaller and less noticeable
Bald Eagle
- Cere Color: Yellow
- Cere Shape: Large and protruding
Peregrine Falcon
- Cere Color: Blue-gray with yellow accents
- Cere Shape: Rounded and enveloping nostrils
Great Horned Owl
- Cere Color: Grayish
- Cere Shape: Heart-shaped facial disk
Barn Owl
- Cere Color: Pinkish-white
- Cere Shape: Distinctive heart shape
Significance of the Cere
While the cere may seem like a small structure, it is vital to birds of prey. The cere’s unique shape and ample blood supply help regulate beak temperature and respiration. Its coloration and fluffy feathers play a role in communication and courtship. The cere also aids food detection in species like vultures. This unassuming patch of flesh and feathers is crucial to the survival of raptors across the globe.
Next time you see a bird of prey like a hawk, take a closer look at its head. You’ll be able to spot the distinctive cere surrounding its sharp beak. This critical plumage allows raptors to thrive as they hunt, scavenge, and soar over landscapes worldwide. The unassuming cere is a little-known but essential accessory for all birds of prey.
Frequently Asked Questions
Why do some raptors have different colored ceres?
The variations in cere color and pattern are related to species differences and serve purposes like communication and thermoregulation. For example, falcons tend to have blue-gray ceres which may help with heat dissipation. Red, orange, and yellow ceres seen on hawks and eagles likely play a role in visual displays and mating rituals.
Do the cere colors change meaning?
Yes, cere colors can change to communicate different information. During breeding season, the cere may intensify in color which signals the bird’s readiness to mate. Some raptors also pale during the non-breeding season. Cere colors and patterns can relay information on age, sex, and behavior.
Why do vultures have such large ceres?
Vultures have expansive ceres with a complex set of folds and bumps containing sensory receptors. This adaptation allows vultures to detect scent molecules as air currents pass over their large cere. Their enhanced “sniffing” ability helps them find carrion from miles away.
Which raptor has the most distinctive cere?
Many point to the barn owl as having the most distinctive cere. The barn owl possesses a unique heart or ace-of-spades shaped cere that is pinkish-white in color. This prominent facial disk helps the barn owl locate prey in low light conditions.
Do baby raptors have a full-sized cere?
No, baby raptors start out with smaller, less developed ceres. The cere grows and gains adult coloration as the birds mature. Young raptors may go through multiple molts before growing their definitive cere plumage. At first their ceres appear flatter and more faded.
Conclusion
The specialized plumage on a raptor’s beak known as a cere plays a critical and underappreciated role for birds of prey. This facial feature allows raptors to hunt, breathe, thermoregulate, communicate, and find food. The cere’s varied shape, size, texture, and color across different species demonstrates its importance for avian predators. Next time you see a bird of prey, take a moment to admire the amazing apparatus that is its mighty cere.