Cere

Bird Bill Anatomy

Cere
Raptors often have prominent ceres. Photo © Vladimer Shioshvili/Flickr/CC by-SA 2.0

Definition:

(noun) A cere is the soft, fleshy, typically bare patch at the base of the upper mandible of the bill of some bird species, particularly many birds of prey, owls, doves, skuas, turkeys, curassows and parrots.

Pronunciation:

SEEER
(rhymes with clear, fear and near)

About the Cere

The purpose of the cere is largely unknown, but it houses the bird’s nares (nostrils) and it is believed to play a role either in respiration or the sense of smell.

It may serve to amplify a bird's senses, or else may work as a filter to keep debris from entering a bird's airways. Further detailed study of the ceres of different bird species is needed to definitively determine what the structure does and how it operates, as well as how birds without a cere perform those same functions.

The texture, size and color of the cere can vary depending on the species. In some cases, the cere will indicate age or even gender, as with the different colored ceres between male and female budgerigars. Waxy and swollen appearances are common appearances of many ceres, and in fact the word cere derives from the Latin cera, meaning wax. Despite the name, however, the cere does not create or exude wax, and in fact, any type of visible discharge from the cere is a sign of illness or injury.

What a Cere Isn't

It is easy to mistake the cere for different parts of a bird's bill, but understand the differences between different structures can help birders better understand the cere.

A cere is not a bird's...

  • : These are the nostrils, the actual nasal openings a bird can breathe through. Nares may be surrounded by the cere, but they are separate, distinct features.
     
  • Lores: The lores are the patch of feathers or skin directly behind a bird's bill and in front of the eyes. The cere does not extend as far back as a bird's lores, but a swollen or prominent cere may seem to be part of the lores.
     
  • : These are prominent, stiff feathers at the base of a bird's bill. These feathers may extend over a bird's cere, but they are not part of the cere itself.
     
  • Basal Knob: This is a different type of feature, a swollen, prominent bump at the base of a bird's bill. Like the cere, much of the basal knob's function is not well understood, but they are different, unrelated features.

Identifying Birds by the Cere

If a bird has a clearly visible cere, it can be a useful field mark. Not all birds have distinct ceres, therefore a visible cere can help narrow down a bird's species quickly. The color, size, shape and texture can all also be great clues to the specific bird showing a cere, particularly if the cere contrasts well with the bill or the facial plumage coloration. Furthermore, the cere characteristics can help identify bird genders, note juvenile birds or even denote subspecies in some circumstances. In some birds, the cere will change color during the breeding season, indicating whether a bird is ready to mate or may be less desirable a partner.

When examining a cere, also look for adjacent structures and how they relate to the cere, such as:

  • The size, shape and position of the nares
  • The color of the lores
  • The color and prominence of the gape
  • The presence of any rictal bristles
  • Other overall bill characteristics, including size, shape, curvature, color and markings

Examining the cere can also be helpful to note a bird's physical condition and general health. Some species, such as many parrots and doves, have a naturally swollen, puffy or bulbous cere. If the skin is overly swollen or appears discolored at the edges, however, it can be a sign of infection or several different wild bird diseases. A crusty or scaly quality to the skin is another indication of poor health, as is any mucous discharge. A bloody discharge, on the other hand, is a likely sign of severe injuries, such as a head impact from a window strike or similar collision. If such injuries are noticed, it may be necessary to contact a licensed bird rehabilitator for assistance to give the bird proper care for a successful recovery.